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Overlapping attic on wooden beams pie. Cold attic ceiling insulation: features, device and recommendations

There are two types of attic space - a cold attic and a combined attic or attic. In a cold attic, insulation is laid horizontally on the floor of the attic, and the temperature inside the cold attic is about the same as outside.

The temperature inside the cold attic should not exceed 4 °C of the outside temperature (rules and norms for the technical operation of the housing stock, Decree No. 170 of September 27, 2003, clause 3.3.2), i.e. if the temperature outside is -15 °C, then in the attic it should be no more than -11 °C. If this difference is greater, then, for example, at an outdoor temperature of -5 ° C, the slope will heat up, the snow on the roof will melt and drain onto the eaves. The cornice will not heat up, because. there is no warm room under it, and the water on it will turn into ice, forming icicles. The more ice will form on the eaves, the greater the chance of leakage, the greater the load on the roof and the greater the danger of ice breaking, which can lead to tragic consequences. All this reduces the service life of both the roofing and the roof as a whole.

Rice. 1 Cold attic ventilation.

To ensure normal temperature conditions in a cold attic, it is necessary, first of all, to insulate the ceiling between the attic and the living space. The thickness of the insulation is calculated based on several parameters, the main of which is the location of the house. The second most important criterion for observing the temperature regime of the attic space is under-roof ventilation.

In addition to insulation and ventilation, the temperature regime of the attic space is affected by: uninsulated manhole covers for access to the attic, the outlet of ventilation pipes to the attic space (kitchen, bathroom), non-insulated hot water distribution located in the attic, and so on.

Roofing cake for a cold attic can be divided into two parts. The first part is on the floor between the attic and the living quarters. The second part is on the slope.

The first part of the roofing pie, depending on the type of flooring, looks like this:

Rice. 2 Pie on a concrete floor.

Rice. 3 Pie on a hardwood floor.

Vapor barrier is used to prevent the entry of moist air from the room into the insulation. On a concrete base, it is best to use bituminous roll material, with overlapping. On the logs, a film vapor barrier is used with the obligatory gluing of overlaps with sealing tapes. As a vapor barrier, use D-Folie B, D-Folie B 90 or D-Folie BR vapor barrier films.

The insulation is laid in several layers with a spacing of joints to eliminate cold bridges.

The hydrowindproof membrane protects from a weathering of heat and hit of moisture. Moisture can form due to condensation, due to snow blown into the attic space, as well as due to possible leaks. D-Folie A 150 or D-Folie A 100 superdiffusion membranes must be used as hydrowind protection.

In any case, regardless of the type of overlap, it is not recommended to cover the insulation from above entirely with plywood or boards. If it is necessary to occasionally walk around the attic space, it is better to provide paths from the boards, without covering the entire insulation.

The second part of the roofing pie using flexible tiles in a cold attic looks like this:

Rice. 4 Roof cake for a cold attic.

dokepie.com

How to arrange a roofing pie under a soft roof: general principles and analysis of construction options

To an uninitiated person in the intricacies of construction, a roof is presented as a cover that is accessible to the eye, protecting his household from weather adversity. In fact, this is a complex structure, each element of which must flawlessly perform the work entrusted to it. The components are stacked in layers like a culinary product that shares its name with the roofing system. Layers are laid with a certain sequence, the violation of which threatens with a noticeable decrease in consumer characteristics. The service life of the roof and the heat engineering of the house as a whole depend on how well the roofing pie is built under the soft roof.

Types of soft roof structures

Roofing cake is a generalized technical term that combines a number of structures with a similar "layered" structure. The combination of layers should protect the owners of the house from atmospheric attacks and protect the internal filling of the cake from premature spoilage.

The standard structure of a roofing pie includes the following mandatory components:

Vapor barrier. Prevents the penetration of evaporation from the interior of the house and the condensation of moisture on the building materials used in the construction of the roof;
Thermal insulation. Contributes to the preservation of heat, protects from noise coming from outside, winds, cold temperatures;
Waterproofing. Prevents the penetration of rainwater and melted winter precipitation into both the roof structure and the building;
decorative coating, which simultaneously performs the work of wind protection.

The category of soft roofs includes materials with excellent waterproofing qualities. Among them are bituminous roll representatives, piece analogues, mastics and a new generation of membranes. A couple of decades ago, they only served as a barrier against water, and now they also successfully play the role of decorative coatings. This is due to the ennobled outer surface and the development of laying methods that allow attaching super-thin materials to any type of base.

The combination of insulating and decorative properties made it possible to reduce the number of main layers in the roofing cake to 3, if one of the types of rolled materials is used to equip the roof.

When laying bituminous tiles, waterproofing is not completely abandoned. However, it is laid as an additional waterproof layer and covers the roof either completely if the slope of the slopes does not exceed 18º, or partially in strips along the overhangs, along the ridge and valleys, around the pipes and at the junctions on roofs with slopes steeper than 18º.

The above list of the main roofing layers has the nature of general recommendations. In fact, it is being finalized by reducing or adding functional elements, because a number of significant circumstances influence the formation scheme of an ideal roof structure, such as:

the type and purpose of the object being equipped, i.e. a residential building or household building;
temporary or permanent use, determining the use or rejection of thermal insulation;
the shape of the roof and the steepness of its slopes, directly related to the choice of materials for roofing;
type of base for arranging a pie and laying a soft roof;
the presence of an operated or non-operated attic;
regional climatic features, according to which the thickness of thermal insulation is determined;
compatibility of structural layers, as in case of incompatibility, separation or migration layers will be required.

A well-arranged pie for a soft roof is constructed taking into account the full range of the listed conditions. Without information about the specifics of the project, no one will give exact recommendations, but it is worth familiarizing yourself with the principle of construction, regardless of whether the cake will be arranged with your own hands or hired roofers will be engaged in laying it.

The principles of the roofing pie

Consider the most common pie schemes for a soft roof used in private construction. Flat and low-pitched roof structures are rarely built over low-rise buildings. However, there are adherents of strict cubic forms of techno or hi-tech style, and their number is steadily growing. Most often, flat roofs are erected over bay windows, attached terraces, utility compartments of a building, garages, etc. They are covered with bitumen-polymer materials or a membrane, laid on reinforced concrete floors or a base of galvanized profiled sheet.

The most popular in private construction is bituminous shingles, used in the arrangement of pitched roofs with a slope of 12º or more. It is mainly used to cover the truss system erected both over summer cottages and over country houses. Let's start with her.

Roofing cake for flexible tiles

Soft tiles cover buildings with cold attics and houses with insulated attics, in the designs of which, of course, there are radical differences. In the first case, there is no need to use heaters, in the second case, thermal insulation is a mandatory component. Both options require the installation of a continuous crate from an antiseptic-treated board, sheets of moisture-resistant plywood or OSB-3 oriented strand boards.

The simplest non-insulated option

The scheme for laying a soft roof over an uninsulated attic is extremely simple:

a counter-beam installed across the rafters is nailed to the rafter legs. The recommended size of the bar is 50 × 50, it is attached with two nailed nails to each rafter. The installation step of the counter beam depends on the step between the rafters. If the distance is standard 0.7-0.9 m, the bar is nailed after 30 cm;
slabs of a continuous crate are laid on a counter beam in a run-up so that there are no cruciform joints between them. The edges of the slabs must rest on the elements of the counter-lattice. The plates are fixed after 15 cm with nailed nails to the bar;
a self-adhesive waterproofing carpet is laid, the laying of which is carried out depending on the steepness of the slopes. At a slope of 18º or more, only slopes, ridges, valleys, junction areas and pipe passages through the roof are covered with waterproofing. Less steep roofs are completely covered with an insulating carpet;
a soft tile is mounted on top of the waterproofing barrier.

If a continuous crate is constructed from a board, then the need for a counter-crate device is automatically eliminated. The boards are fastened immediately to the rafter legs, laid with a gap between the elements of 3 mm.

Insulated roof device

The cake for an insulated roof is much more complicated. Its design is complemented by thermal insulation. And since it is, then you will need a vapor barrier material that protects the insulation from moisture accumulation. The result of moistening is a decrease in insulating characteristics and the accompanying decay processes with subsequent destruction. You also need ventilation, designed to remove condensate from under the roofing, which is unable to pass drops that are dangerous for wood on its own.

The scheme for laying layers of a roofing cake for an insulated pitched roof, which involves the operation of an attic, is as follows:

on the inside of the rafter system, a vapor barrier membrane is attached directly to the rafters with a stapler. It is laid parallel to the overhangs in strips from the bottom up. In a single canvas, the strips are connected with double-sided tape;
according to the arranged vapor barrier, again from the inside, a counter-lattice is constructed from a bar, the installation step of which depends on the material of the planned inner lining of the attic. For example, under plasterboard sheathing, it is desirable to place the lathing bars at a distance of 40 or 60 cm;

auxiliary struts are mounted on the outside of the roof between the rafters. They are required to hold the insulation boards. Spacers are placed in increments of 2-3 cm less than the height of the heat-insulating plate. So it is necessary that the thermal insulation is rigidly fixed in the compartments created for it, “straightened out” after light compression during the installation process;
in the resulting semblance of honeycombs, a heat-insulating material is placed, the thickness of which should be 3-5 cm less than the thickness of the rafter legs. This is a necessary condition for proper ventilation of the roofing cake;
the counter-lattice is being built again. It is nailed to the rafter legs along their direction in order to form ventilation ducts - roofing vents;
a solid crate is attached to the outer counter-lattice, on top of which an additional waterproofing carpet is laid;
soft tiles are laid.

For the installation of a warm roof with soft tiles in the northern regions, it is sometimes not enough to have a mineral wool insulation thickness of 15 cm - a generally recognized standard for the middle lane. Then, from the outside, a counter-beam tier transverse to the rafters is first mounted for laying the second layer of insulation, then a bar along the rafter legs for the installation of a continuous counter-lattice.

If bituminous tiles are planned to be laid over low slopes constructed from reinforced concrete slabs or arranged by means of a slope with a cement-sand screed poured on top, the vapor barrier is laid on a concrete or cement-sand surface. A board is installed on top of the vapor barrier on the rib in increments of up to 90 cm, and then the required number of tiers of the counter-lattice.

A roofing pie with wooden elements cannot be closely adjacent to chimney pipes. The indentation from the pipe walls laid down according to the norms can be found in SNiP 41-01-2003. The empty space is filled with non-flammable mineral wool material, and an apron made of galvanized or laminated metal is installed around the pipes.

The stages and principles of arranging a roofing pie for soft tiles will be presented by a video:

Roofing cake for roll materials

For the arrangement of roofs with a slight slope angle, with a spread that way from 1º to 12º, bitumen-polymer materials or roofing membranes are used. There is simply no point in laying piece shingles on them. And the patterned aesthetics of flexible tiles on flat and almost flat roofs will please only birds.

There are no special differences in the set of layers for piece and roll material. The sequence is similar: vapor barrier → insulation → hydrobarrier - it is also a decorative coating and wind protection. However, the installation of a roofing pie has its own specifics. Solid crate and counter beam are not used. Layers are laid without auxiliary wooden elements on concrete floors, cement-sand screeds, profiled sheets, prefabricated leveling structures. Therefore, we focus not on the sequence of installation actions, but on the features in laying.

Principles of a vapor barrier device

The vapor barrier layer for laying rolled materials are materials such as:

bituminous and bitumen-polymer vapor barrier welded onto a concrete or cement-sand base, including cement-sand insulation with vermiculite, expanded clay, perlite in the form of filler in case of a slope slope of more than 6º. If the slope is less, the bituminous vapor barrier can be laid without gluing or fusing to the substrate.;
polyethylene reinforced or non-reinforced vapor barrier, laid freely along the corrugations of a profiled sheet or glued to it in case of slopes of more than 6º.

Any type of vapor barrier material can be used in the construction of a soft roof over prefabricated screeds made of plywood or OSB boards, but the recommended option is a bitumen-polymer vapor barrier with a polyester fabric backing. However, it is also not forbidden to put polyethylene on a concrete surface, but before that, a separating layer of glassine should be arranged.

The vapor barrier layer is laid in the form of a kind of pallet with entry to the vertical planes of adjacent walls and parapets. The height of the sides of the pallet is calculated as follows: the thickness of the heat-insulating layer plus 3-5 cm. Similar sides are arranged around the intersection of the roof with chimney pipes and other communications.

Both vapor barrier options must be connected into a continuous web. Strips of bituminous and bitumen-polymer material are laid with an overlap of 8-10 cm on the sides and 15 cm in the end joints and welded with a gas burner. The connection of polyethylene strips is made using adhesive tape.

Rules for laying thermal insulation

It is possible to insulate a soft roof with a roll coating with literally any material, but mineral wool boards and expanded polystyrene are considered priority. On concrete bases and cement-sand screeds, the insulation system is laid in one tier, on corrugated board in two so that the joints of the elements of the upper row are not located above the joints of the lower layer.

The hardness of mineral wool for single-layer insulation is 40 kPa with a compressibility of 10%. For the construction of two-tier thermal insulation, it is not necessary to use plates with equivalent rigidity. The bottom row can be folded with a material with a strength of 30 kPa, the top 60 kPa.

If a polymer membrane is used as a waterproofing and decorative roofing, a separating layer of fiberglass or geotextile must be laid between it and polystyrene thermal insulation. Otherwise, the membrane will lose its consumer qualities before the period guaranteed by the manufacturer due to the gradual migration of plasticizers into the neighboring material. A separating layer is also required when installing an inverted ballast roof, if the polymer coating spreads over the bituminous vapor barrier layer.

Laying of mineral wool boards on corrugated board without preliminary construction of a prefabricated screed from plywood or OSB sheets can be carried out if the thickness of the thermal insulation is twice as large as the distance between adjacent corrugations. If reality does not meet this condition, a prefabricated screed is constructed before laying the insulation.

The device for thermal insulation under the roll coating requires compliance with the following rules:

heat-insulating material is attached separately from the coating laid on top;
with a mechanical method of fastening, each thermal insulation plate and its separate part is fixed at two points. The insulation is fastened to the profiled sheet with steel self-tapping screws with a plastic sleeve in the form of a fungus. Plastic bushings are not used if the ramp slope is greater than 10º. In any case, they are attached to the concrete base with self-tapping screws with dowels and metal plates;
gluing of insulation boards is carried out on bitumen-polymer mastic. Bonding is possible if the area “planted” on the adhesive composition of the surface is at least 30% of the area of the insulation board;
insulation boards are laid with a mandatory expansion of the seams so that the weak areas are distributed evenly. The elements of the second tier, if any, are displaced relative to the first by at least 20 cm, both along the side and end lines;
seams in the insulation mat with a width of more than 5 mm must be filled with heat-insulating material.

The use of rigid insulation is justified economically and technologically. It allows you not to arrange a screed on top of the insulation, which is mandatory for backfill thermal insulation.

If it is necessary to build a roofing slope to completely free the surface from atmospheric water and dirt, the thermal insulation is supplemented with slope-forming devices. Most often they are made from wedge-shaped mineral wool slabs or from similar polystyrene foam parts, less often from bulk insulation, followed by pouring a cement screed. Razklonka on a concrete base can also be done by means of cement-sand pouring, which is unacceptable for the formation of a slope on the basis of a profiled sheet.

Additional layers of roofing material

An additional atmospheric water barrier is placed in areas of increased load. It is laid in strips along the ridge, overhangs and junctions with pre-built fillets, in valleys, around penetrations and points of internal drainage. It is arranged either from strips of roofing bitumen-polymer coating, or from a special self-adhesive hydrobarrier.

The construction of the roofing pie is completed by laying the rolled coating and fixing it by fusing, gluing or fastening with self-tapping screws with bushings or plates.

In the presented schemes for the construction of a roofing pie, there are no exact recommendations. We have given general rules, the consideration of which will ensure the perfect operation and long life of the roof in the middle lane. In the case of construction in northern latitudes, the proposed options require further development.

krovlyaikrysha.ru

What is an attic

The attic space is limited by the slopes of the roof and the ceiling of the residential floor. This place is often used for arranging additional living space.

The attic of private households is of two types:

Residential. It is called the attic. It can be equipped with a living room, study, bedroom, library, etc. The height of the room in this case should be at least 220 centimeters. In addition, it is necessary to provide ventilation, natural lighting, and insulate the slopes.
Non-residential. Such an attic space, as a rule, is used to accommodate technical equipment, store old or unnecessary things. In this case, a 2-meter height will be enough, and it is not necessary to equip natural lighting. Instead of insulating the slopes, they make the thermal insulation of the attic floor.

When deciding to repair or rebuild a house, you need to decide in advance for what purposes the attic will be used in order to make a calculation and a floor project. The list of necessary materials and the gap between the beams depend on this. They must provide the required strength and bearing capacity.

Functional purpose of floors

The design of the attic floor depends on the parameters of the structure and the purposes for which it is planned to use the under-roof space. The function of a kind of air gap is assigned to the attic, which separates the cold roof from the heated floors.

The floor in the attic performs a number of tasks:

carrier. The floor, located between the upper living floor and the attic space, is assigned a bearing function, therefore it is made reliable and durable, since people will move along it, they plan to place equipment on it and equip storage places;
insulating. In a cold attic room, the temperature differs little from that outside the house. In this case, the floors in the attic have a thermally insulating function, thereby preventing air cooling on residential floors. To keep warm, thermal insulation of the attic floor is required. It is advisable to entrust such work to professionals.

Features of the device and the design of floors

Since attic floors perform two functions - load-bearing and insulating, they have a multilayer structure. Each of the elements of the "pie" complements each other, which provides the created structure with a long service life, strength and ability to withstand heavy loads.

The device of the floor in the attic assumes the presence of the following layers:

Finished floor. This name was given to the floor covering, which is laid on a rough base. If this is an attic, then when arranging the finishing floor, linoleum, laminate, parquet, etc. are laid. In non-residential premises, the finishing floor covering may be absent.
Draft base. It is a boardwalk, which is mounted on logs. The draft floor is lined with edged boards 4–5 centimeters thick or, in order to save money, from unedged boards.
lags. These are strong, even wooden elements laid perpendicular to the floor beams to create a floor covering. When the attic floor is being arranged on wooden beams, a heater is placed between the lags, which is protected from below with a layer of vapor barrier, and covered with waterproofing material on top. If you do not apply insulating layers, then repairs will be required after a few years.
beams. The frame of the floors is built from thick and durable beams, which are either mounted on the ledges of the walls or embedded in them. They must support the entire weight of the structure.
ceiling lining. From the side of the rooms, the floors are decorated with finishing materials, for example, natural wood or drywall.

Types of attic floors

For the device of overlapping a cold attic, materials are used that differ in weight, durability, cost and bearing capacity.

There are several types of floors, depending on what they are made of:

wooden elements. For their manufacture, beams with a cross section of 150x150 or 200x200 millimeters can be used. The advantage of this option lies in the fact that the tree is strong enough and at the same time relatively light material, so the wooden elements do not put additional stress on the foundation of the house. In addition, their great advantage can be called a small price and availability. But such an attic floor is used when the size of the building does not exceed 6-10 meters, since this is the maximum length of lumber.
metal products. I-beams made of metal are durable, able to withstand heavy weight without deformation. But they weigh decently, so they are rarely used in wooden houses, but for brick and aerated concrete buildings they are the best option.
Reinforced concrete products. Molded floor beams made from reinforced heavy-duty concrete are used for multi-storey buildings, since they are heavy and of the same length.

Of all the above types of floors in private low-rise housing construction, in most cases, preference is given to wooden beams. They have the best balance between price and quality. With well-executed calculations and compliance with the technology, repairs to the ceiling in the coming years will not be required.

Requirements for the device of the pie

Since the safety of staying in the house depends on the quality of installation and repair of attic floors, a number of requirements are imposed on their arrangement.

In order to know the value of the maximum allowable load that the structure can withstand, it is necessary to perform the appropriate calculations, and then, based on their results, they begin to develop a project from which it will be clear how to properly insulate the attic floor in the house.

Requirements apply to:

Bearing capacity. It directly depends on the material of manufacture of the beams and on the gap between them.
Distances between bearing elements. The maximum allowable value for this parameter in accordance with building codes is 4 meters.
Resistance to temperature changes. It is necessary that the beams can withstand such changes without problems. The fact is that the difference between the air temperature in residential floors and in the attic always exceeds 4 degrees.
Isolation. The attic floor cake of a cold attic should protect the premises of the household from the penetration of cold and moisture from the under-roof space.

In the design process, the requirements for the beams used for arranging the floor in the attic should be taken into account so that the result is reliable and durable. The distance between them must be calculated based on the loads exerted on them.

Technology for creating an attic floor on wooden beams

If you have experience in performing construction work, you can mount the ceiling of a cold attic on wooden beams with your own hands. Perform this process at the final stage of the roofing work.

The sequence of actions will be as follows:

Installation of load-bearing beams. For a small private house, wooden floors made of timber with a section of 150x150 or 200x200 millimeters are suitable. They are laid on concrete or brick masonry walls.
Log installation. They are placed on the edge perpendicular to the beams with a step of 60 centimeters. Logs are made of boards with a section of 150x50 millimeters.
Thermal insulation lining. Insulation is placed between the lags - it will protect against the penetration of cold from the attic.
Installation of rough and finishing floor.
Sheathing of load-bearing beams from the side of the room in order to decorate the surface of the ceiling.

When insulating the attic floor, one should not forget about the arrangement of hydro and vapor barriers.

kryshadoma.com

Cold loft design

When building the roof of a house, many people think about making a cold attic or attic under it? The easiest way to organize a roof with a cold attic. Building an attic will cost several times more and will require more labor costs.. Although, it is undeniable that the attic will significantly expand the living space.

Cold loft roofs have the following main ingredients in their pie:

roofing;
attic outer walls (applicable for gabled roofs with gables);
insulated ceiling between living space and attic.

Ventilation is provided by eaves and ridge ducts. The air passing through the cornice openings is called supply air, and the air exiting through the ridge is called exhaust air. Additionally, ventilation can be done through dormer windows on gables or roof slopes. Windows are equipped with louvered grilles for the possibility of adjusting the intensity of ventilation.

Dormer windows are located on opposite roof slopes so that there are no unventilated areas.

Dormer windows can be rectangular, triangular and semicircular. Their lower part should be at a height of no more than 0.8-1.0 m from the floor in the attic, and the upper part should not be lower than 1.75 m from the floor in the attic. They can also serve as an exit to the roof of the house to inspect the roof, ventilation and chimney elements.

Steam and thermal insulation of a cold attic

For a roof with a cold attic, it is most important to minimize heat loss through the attic floor. For both wooden and reinforced concrete floors, vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator, passing through the ceiling of the living space. As a heater, plate and bulk materials can be used. The ceiling pie consists of a vapor barrier, floor beams and insulation.

The following types of heat insulators are often used in ceiling ceilings:

polystyrene and foam boards;
mineral wool boards or mats;
expanded clay granules;
fuel or granulated slag;
sawdust with lime or clay;
pumice.

The thickness of the required insulation layer is selected depending on the calculated winter temperature using the table below.

Winter temperature is calculated according to SNiP 2.01.01-82 (construction climatology and geophysics) or is selected by regions of the Russian Federation from the corresponding climate maps.

Insulation is placed between the joists or beams of the ceiling, and a plank flooring is made on top for attic passages. Logs are usually 50 mm thick, and deck boards are 25-35 mm thick.

For ventilated attic spaces, soft or semi-solid heat-insulating materials are considered the most optimal.

Attic waterproofing device

Waterproofing roofs with a cold attic, according to many experts, is a controversial issue. Some say that waterproofing must be present under the roofing material, and someone categorically recommends abandoning it. Much here depends on the type of roofing material and the angle of inclination of the roof slopes.

Metal roofs are most susceptible to corrosion that occurs with possible small leaks or from condensation. Therefore, once again we draw your attention to the fact that ventilation plays one of the main roles in the fight against condensate.

For flat metal roofs, experts recommend installing superdiffusion membranes. It will prevent moisture from entering the outside of the roof when blowing snow or rain. No matter how well the roof is laid, there is always the possibility of minimal leaks. That is why, having overpaid a little, you will receive additional protection against moisture ingress on the insulation in the ceiling of a cold attic.

Possible leaks or condensate when it gets into hydrophobic heaters significantly reduce their heat-insulating properties.

If, for example, slate is used as a roofing material, then waterproofing can be abandoned. There is also a corrugated board with an anti-condensation coating on the market, which can hold up to 1 liter of water per 1 m 2. For our part, we recommend that you always use waterproofing membranes, because this is the cheapest and easiest additional way to protect your roof from possible leaks.

When installing waterproofing membranes, a counter-lattice is used. It performs the function of a fixing rail and, due to its height, provides the necessary clearance for ventilation of the under-roof space. The device of the crate of a cold attic is no different from insulated roofs. The dimensions of the crate and its pitch determine the type of roofing to be installed.

Temperature regime of a cold attic

To prevent ice and icicles from forming on the roof, it is necessary to maintain the correct temperature and humidity conditions in the attic. With insufficient thickness of the heat-insulating material, significant heat losses occur through the ceiling. Warm air, heating the roofing, causes snow to melt and ice to form. By choosing the right layer of insulation, this can be avoided.

You can evaluate the effectiveness of a heat insulator using a temperature measurement of the top layer of insulation. An electronic thermometer is immersed in a heater by 10-20 mm. The temperature readings taken must match the values in the table below.

As you can see, the arrangement of a cold attic pie does not differ in particular constructive complexity. The main task is to provide the necessary intensity of ventilation and the thickness of the heat-insulating layer in the ceiling ceiling.

If you are finishing building a house, almost finishing work has already been done and you don’t know whether to take on the attic or whether this business can wait, and in general what is needed at this stage, this article will help you. Here we look at attic insulation with different types of materials, with step-by-step illustrations, expert advice and a helpful video.

We will also reveal many important points why insulation is so necessary and what the attic floor pie should actually be like on wooden beams and on a reinforced concrete slab - step by step.

What insulation is suitable for the attic?

It is necessary to insulate the attic floor when the attic space is not planned to be used for housing. Those. we are talking about a cold attic, the roof slopes of which are not insulated at all. And far from all the same materials are already suitable for overlapping, they are selected for slopes.

Mineral wool: no harmful dust

So, when insulating the attic floor with mineral wool, it is correct to use the so-called tension method. Its essence is that first the insulating material is laid - and so that it registers between the beams.

After that, a slab or rolled mineral wool insulation with a total thickness of about 150 millimeters is laid on it in three layers, and it is covered with a vapor barrier film on top. After that, plywood, which should be no thinner than 18 millimeters.

Expanded polystyrene and foam: ease of installation

High-quality insulation of the attic floor with polystyrene foam is also obtained, the main advantage of which is that there is no need for vapor barrier, and all gaps are easily sealed with mounting foam.

Inflatable insulation: fashion and rationality

Recently, it has become especially popular to insulate the attic floor by blowing.

The main advantage of blown insulation is that it fills all the voids that exist by itself and creates an even continuous layer. In which there are no joints, no seams and no adjoining, and for which there is no need to cut separate small pieces of prickly insulation to plug something.

Today, for the insulation of cold attics in Russia, two types of blown insulation are mainly used: ecowool and blown wool.

Ecowool up to 80% consists of cellulose fibers, which are produced from ordinary waste paper, and 20% from additives such as snowstorm as a fire retardant and boric acid as an antiseptic. Such a heater has a high thermal conductivity.

But blown wool is obtained by grinding ordinary mineral materials for thermal insulation, which for some reason did not pass the product acceptance.

For example, they did not have sufficient density or the correct structure of the fibers. And such material is crushed and packed under high pressure, and therefore it is easy to transport it to the site of the facility, where everything will be loosened again upon arrival.

But still, ecowool is most often used as a material. The insulation itself in the process looks like this: one person must remain near the installation and monitor its normal operation, while loading the material. And the second person goes up to the attic with the hose, makes a cruciform incision on the vapor barrier (just between the beams), inserts the hose into this incision, and fills the cavity with material.

Plus, relatively inexpensive bulk materials are used to insulate a cold attic:

What parameters of the heater should be paid attention to?

In no case do we urge you to purchase the most expensive heat-insulating materials to insulate your attic floor. But note that the more and longer any well-known company produces materials for this purpose, the more it pays attention to quality, changing their bulk density, improving their products and increasing thermal insulation coefficients. And that already says something.

For the rest, always pay attention to such parameters of heaters that are important for a wooden floor, and have none for concrete - and vice versa.

Parameter number 1. Biostability

We are talking about the fact that in such a heater, which often remains open, bugs or some other living creatures do not start. This is especially true of mice, who love to live in a warm and dry (and, most importantly, deserted) attic.

Another important requirement for attic insulation is water resistance. Raindrops accidentally falling into it or simply moisture should not lead to the process of decay.

Glass wool is recognized as one of the most resistant heaters:

Parameter number 2. Thermal conductivity

The main requirements for insulation for the attic floor is the ability to maintain thermal insulation properties for a long time.

When buying a heater, also pay attention to such an interesting point: modern manufacturers of thermal insulation materials always indicate in the technical specification three coefficients of thermal conductivity of the material at once: in a dry state, at a temperature of 10 ° and 25 °, and humidity categories A and B.

You need to look at the coefficient of thermal conductivity in a dry state, or at a temperature of 10 degrees, because this is exactly the normal climatic situation in the attic. For a more accurate and detailed thermal calculation, you will need a SNiP table.

Now let's take a moment. When choosing a heater, you will probably be advised to take a heater with the lowest possible degree of thermal conductivity. But in fact, this only makes sense for residential attics, because when you have to insulate the roof slopes, then too thick materials cannot be laid between the rafters. Therefore, materials are needed here that will conduct heat as poorly as possible, but at the same time have a small thickness.

But for the attic floor, just the thickness of the insulation is not a critical factor, and you can save on this. Just take a cheaper insulation, but thicker, albeit with high thermal conductivity. You are all compensated by the height of the insulation itself.

Parameter number 3. Weight

Depending on the chemical composition, each insulation has its own volumetric mass. So, materials such as basalt, glass and any other inorganic and organic compounds are most often used as the basis for fibers. From their type, the heat-insulating material itself becomes either light or heavy. And the shape of all these materials is provided precisely by the elasticity of the fibers: how much they straighten between the floor beams.

Note that heavy insulation keeps its shape better due to the rigidity of its fibers. And foam insulation has the best stability for attic floor insulation, which in this parameter is equated to hard stone wool. But there is a moment: the same mineral wool insulation that was inserted between the floor beams can be easily straightened and pressed tightly against the wood, but the foam will not do this, and voids form - the bridges are cold. Therefore, you will have to additionally use a can of foam to close all the cracks.

On the other hand, if the attic floor is insulated on a reinforced concrete slab with foam-based materials, then there will only be pluses. Not to mention the fact that the attic concrete floor itself already has a considerable weight and creates a serious load on the walls and foundation of the house, and the use of light insulation for it is only a big bonus.

And unlike the concrete floor, the attic floor is able to withstand a fairly limited load. Therefore, the weight of the insulation in this regard is also not the last moment. After all, there are already many variations here: the same cubic meter of thermal insulation can weigh as much as 11 kilograms, and all 350 - this is the norm.

One of the heaviest heaters is basalt wool:

Parameter number 4. Moisture resistance

Rain moisture or roof leaks accidentally getting into the insulation should not start the rotting process. It is bad if after six months or a year the new insulation begins to decompose from the inside, while emitting an unpleasant smell of dampness.

Therefore, attic floor insulation on wooden beams and on concrete is quite often done using polystyrene foam or polystyrene foam, which are known for their almost zero hydrophobicity.

Parameter number 5. Environmental friendliness

Another point: the attic insulation should not emit any toxic and pungent substances in terms of smell, despite the fact that, perhaps, no one will walk in such an attic.

It's all about ventilation: sooner or later, the insulation molecules are picked up by air and brought into the living quarters, which is unsafe for the residents of the house. Therefore, choose a heater that meets sanitary standards.

Parameter number 6. Shape saving

Another important point is the form stability of the selected insulation. So, special laboratory tests have shown that over time, heat loss through the gaps between the plates or the matte heat insulator can reach 40%. And this despite the fact that the material itself during the same time may not change its thermal conductivity at all, if at the same time it remained dry.

Therefore, the stability of the shape and dimensions of the material over time is very important. For the concrete floor of the attic, such gaps will not be critical, because here the floor itself is quite heat-insulating, which cannot be said about the attic floor.

But the problem is that in the technical information for modern heat insulators such a parameter as shape or stability cannot be found.

Parameter number 7. Fire safety

And the last point: attic insulation must meet all fire safety requirements. Take the same popular ecowool, which is not just made from ordinary waste paper and pieces of newspapers. It would seem that everything is simple and ingenious, why don't you cut the paper into smaller pieces too, and just fill the attic with it? Would it be worse? After all, the principle of friability is also involved here, like in animal hair, when air molecules get stuck between small elements.

Let's just say: yes, the insulating properties of this method will not be worse, but it is the old dry paper and wood that most often leads to an unexpected fire. That is why modern cellulose insulation is necessarily treated with special chemicals against fire.

If we are talking about the combustibility of materials, then it is important that the insulation not only does not burn, but also has attenuation. Just remember that everything burns at the epicenter of the fire, both iron and concrete, but if a spark falls on the attic floor, then the insulation should not light up. That's what it's all about.

This is what the attic insulation cake itself should look like:

Vapor barrier questions: how, on which side and is it necessary?

For the insulation of roofing made of wood and concrete, the vapor permeability of the insulation is of great importance. So, all heaters that are made today in the form of plates and rolls can be conditionally divided into “cotton wool” and “foam”, as building contractors like to do.

To "cotton" we will refer heat-insulating materials from organic and mineral fibers - these are mineral wool, stone wool and glass wool insulation. All these materials are formed by the hardening of plastic masses of very different chemical origins. And all these materials have approximately the same coefficient of thermal conductivity: within 0.04.

All these materials are made up of fibers that are intertwined with each other. They do not form any closed pores, and water vapor easily enters and escapes through them. Therefore, all wadded heaters are vapor-permeable materials. Why, under production conditions, their fibers are additionally coated with a special water-repellent substance, and the heaters also turn out to be hydrophobized: a water molecule from water vapor is not allowed to penetrate and wet the insulation. It can only cling to its surface, and when a critical mass accumulates, it transforms into drops and rolls down. It turns out that hydrophobized cotton wool insulation is not a wet vapor-permeable material.

Therefore, until now, scientists from all over the world cannot come to an unambiguous conclusion: the vapor permeability of building insulation is good or bad. Let's just say that if you equip the attic floor on wooden beams, you'd better lay vapor-permeable materials on it so that the wooden rafters, which have taken on moisture from the lower living quarters (and water vapor always rises), can freely give it to the insulation . And they will easily come out of the insulation - through ventilation alone is enough. But in terms of floor insulation on concrete, there is not much difference. But there is such a moment here: when using vapor-permeable heaters, it is important that the ventilation of such an attic is organized in accordance with all the rules, and a separate ventilation system will not interfere.

Note that there are no fibers in foam insulation, since such material is literally made from air. All foam insulation consists of a cellular structure, with closed bubbles and not closed, like a kitchen sponge. Therefore, such heat insulators can be both vapor-permeable and non-vapor-permeable. For example, extruded polystyrene foam, which is better known to us as polystyrene, passes water vapor between the balls, but extruded polystyrene foam does not.

Interestingly, you can use not only one type of insulation, but two at once to compensate for each other's shortcomings. But at the same time, a heat-insulating material with a lower vapor permeability must necessarily lie in front of a heater with a high vapor permeability. That is, first polystyrene foam, then cotton wool. Otherwise, in the opposite case, a material with a lower vapor permeability will become a certain vapor barrier for another material, it will simply begin to rot and there will be nowhere for moisture to go.

How to insulate a concrete attic floor

If we are talking about the insulation of the attic floor of concrete, then the thermal insulation must necessarily be in the form of two or three layers with overlapping joints of each lower layer. Moreover, it is very important that the entire surface be leveled so that there are no irregularities of more than 5 millimeters anywhere - this is not difficult to achieve with the help of modern leveling compounds.

For concrete attic floors, extruded polystyrene foam slabs are ideal as thermal insulation. They don't need a vapor barrier, but if you put styrofoam - it's not extruded polystyrene foam, and then, of course, you need it.

Additionally, if you later need to walk on such a floor, you can make a cement-sand screed up to 4 centimeters and put two layers of drywall sheets. Just be sure to make masonry mesh paths for such a screed that you will walk along. Be sure to glue the joints between the foam polystyrene plates with tape so that cement milk does not leak between the plates.

The attic floor itself can be insulated both at the manufacturing stage and at almost any time during the operation of the house itself. Of course, for the attic it is much more correct to insulate the floor even before you move into your new home.

More details about the process itself:

How to insulate a wooden attic floor

So, there are two main ways to insulate the attic floor: laying a heat-insulating layer inside the structure of the attic floor, and laying insulation on top of it. For a cold and non-residential attic, it is not necessary to cover the insulation with something on top and build a full-fledged floor. But then be sure to leave the running ladders - separate paths from the sparse flooring throughout the attic area, this is necessary for roof maintenance.

Under the insulation, you need to put a vapor barrier, and in the form of a trough, so that it can protect the insulation from water vapor, which comes from the lower living quarters. But there is an exception to this rule: if the insulation was laid with good resistance, for example, it is foam or extruded polystyrene foam, then vapor barrier is not needed here. But if we are talking about an attic with a particularly wet regime, for example, above a kitchen or a sauna, then a vapor barrier layer must be installed here.

Another method is tension, when the vapor barrier only sags slightly between the beams. The disadvantage of this method is that in this way the insulation between the beams is not inserted tightly enough.

And if the overlap is also made from ready-made companies, then this option is not suitable at all, because such voids quickly become the so-called cold bridges. Therefore, in Russia the method is more popular, in which the insulation is first laid, then it is covered with a vapor barrier, and only then - with a finishing floor.

So, this is what the whole process of warming looks like:

Step 1. A vapor barrier is fixed between the beams using a construction stapler.
Step 2. Next, mineral wool slabs are cut so that their width is corresponding to the step of the beams.
Step 3. These plates are carefully inserted into the gap between the beams.
Step 4. For a while, while the ceiling is not yet ready below, so that the insulation does not fall between the beams, it is supported by draft bars or a strong thread stretched especially for this.
Step 5. Next, a diffuse membrane is quickly mounted on top of the insulation - so that steam can easily escape through it, and drops from above from the slopes do not penetrate inside.

But let us also note such a moment about the last step. Many experts believe that no diffuse membranes or windproof films are needed for insulation, because in a cold attic, thermal insulation will dry due to natural ventilation of convection air flows that easily penetrate through holes and dormer windows.

How to leave running ladders in a heater

If you use soft thermal insulation materials to insulate the attic floor, you need to make running ladders above them - but only so that cold bridges do not turn out. Therefore, it is better to take either rigid materials, or insert the legs of the ladders directly into the insulation.

That's all the tricks of warming the attic floor of various types!

High-quality insulation of a cold attic is an important stage in the construction of any house. Thermal insulation will not allow heated air to escape through the roof and protect living quarters from wind and drafts. Insulation can also be carried out in old houses, if such a need arises.

In a cold attic, it is necessary to insulate risers and exhaust ducts that release warm air

According to technical regulations, the attic in the house can be cold or warm. In the cold, and the rest of the space is freely ventilated. In a warm attic, it is necessary to isolate the entire circuit, then the air in the under-roof space will warm up from the exhaust ventilation. A cold attic, the insulation of which should be mandatory, is arranged in multi-storey buildings. An attic room in private cottages is not considered an attic.

The main points in thermal insulation:

When I provide ventilation products. Their area should be at least 0.001 of the overlap area. This rule is valid for roofs with a continuous airtight coating.
If the roof is covered with tiles, slate, and the surface has gaps, then ventilation can be omitted. But this is provided that there is no waterproofing layer under the roofing material.
In a cold attic, it is necessary to insulate risers and exhaust ducts that release warm air.

Insulation of a cold attic is carried out in order to expand the living space due to this room. In other cases, thermal insulation of the floor will be sufficient.

How to insulate a cold attic

All work on thermal insulation can be done independently, if you have the necessary tools and time, read more about insulating the attic with your own hands. Or you can call a professional team that knows how to insulate the attic correctly and quickly.

Cold attic floor insulation

Much depends on the family budget, but experience shows that it is better not to save on materials for warming a cold attic. Thermal insulation can be done:

The prices for the services of our company can be found in the section

Or order a consultation of a specialist at a convenient time for you!

Application absolutely free and does not oblige you to anything!

The attic is the technical area that completes the building. The attic is a technical room, it is rarely used as a living space, equipment necessary to ensure the life of the house can be placed here, engineering networks can be laid. The temperature difference in the residential area and the technical area should be 3 ° -4 ° no more. Therefore, the technical room requires insulation.

Ceiling attic construction

The construction of an attic, which, of course, expands the living space, is much more expensive, requires certain knowledge, time and labor. The device of a cold attic floor is much cheaper and simpler.

The device of the attic floor on wooden beams is a layer cake:

board shield or reel;
vapor barrier;
ventilation gap;
insulation;
ventilation gap;
vapor barrier;

Ventilation is carried out through gables or roof slopes. Dormers are also made, located on opposite slopes, so that air penetrates into all corners of the room.

Dormer windows are an element difficult to install, but useful. They can have a different shape, triangular, oval, they are placed at a height of 1 meter from the floor, equipped with gratings, blinds. Through them it is convenient to go to the roof for its inspection, maintenance, checking the chimney, antenna and other things.

Beams for attic installation

The attic floors are made on wooden beams after the installation of the load-bearing elements is completed. This is the easiest and best way for the competent arrangement of the technical area.

The construction of the attic floor is usually made of wooden beams. These load-bearing elements have a number of advantages:

maximum coverage 4.5 m between supports;
light weight, load on the building, saving on the foundation;
ease of installation, without the use of lifting equipment, a crane;
the availability of wood as an inexpensive material;
speed in work, the ability to install an attic floor in a day or two;
the possibility of using any soundproof materials.

For the manufacture of beams, coniferous wood is used that is resistant to moisture, decay, and fungus. The cross section of the beams for the attic floor must correspond to the load, climatic conditions and the thickness of the heat-insulating material should be taken into account. Use the dimensions of the beams 150x200 mm, if a serious load on the attic floor is expected. For example, it is planned to install a water tank, a transformer. At minimum load, beams of 100x150 mm are used.

The desire to save money and install 50x100 mm beams does not cause approval. Too significant element of the house is the attic floor, which provides thermal insulation, sound insulation and reliability of the ceiling. The quality of the overlap guarantees savings in heat and heating costs.

You can calculate the number of wooden beams of the attic floor as follows. Divide the length of the room by 60-100cm (the distance between the beams), add 2 pieces to the resulting value, which will be laid on the walls. Laying beams should fall on the load-bearing and external walls.

Installation of wooden beams of the attic floor

The device of the attic floor is carried out in several stages, each of which determines the quality and reliability of the structure. The algorithm of work looks like this:

1. Preparation. The required length is cut off, the wood is treated with a special compound that protects against decay, swelling and other troubles, the edges of the beam are wrapped with roofing material, then the finished element rises up.

2. Stacking in two ways:

without protrusion beyond the outer walls;
with outlet for external walls.

It is necessary to lay along the length at the right distance in relation to other structural elements, with any method of laying, the following is taken into account:

the maximum width of the span should not exceed 4.5 meters;
the timber is laid on the ends of the walls, in some cases a Mauerlat is used - this is a thick timber fixed with thick nails or steel studs to the walls around the perimeter;
roofing felt is laid under each beam layer to provide waterproofing;
the pitch of the wooden beams is selected from the dimensions of the heat-insulating material.

3. Attic flooring on wooden beams is carried out taking into account the arrangement of the roll, which is a coating of boards, slabs. Between the upper and lower roll-on, waterproofing, vapor barrier, and insulation are laid. The lower flooring of the floor is made on the supports to which the boards are attached, but it is better to use slabs, plywood sheets with a thickness of 15-20mm. Fastenings are carried out with self-tapping screws in increments of 10-15 mm, so that heat-insulating materials are securely held.

In order to mount the most durable structure, you need to fill wooden bars 50x50mm on the bottom of each beam, they form a ledge on which boards or sheets are placed. You need to fasten the roll to the bars with self-tapping screws. The advantages of this design are exceptional reliability, the disadvantages will appear in the decoration of the ceilings, on which these bars will have to be sealed and hidden. Such a structure should be mounted if active use of the attic is planned.

The value of vapor barrier and how to install it

The vapor barrier of the attic floor ensures the safety of the wooden floor. It prolongs the life of the roof, contributes to the creation of an optimal microclimate in residential premises, taking away excess moisture, and prevents heat loss. The material for the vapor barrier should be chosen carefully, without the intention of saving.

The vapor barrier material has a different side structure. On the one hand, a rough surface absorbs moisture, the other side with a film prevents the penetration of moisture into the heat-insulating layer.

The vapor barrier is laid, as is already clear, between the ceiling and the insulation in the attic floors. Materials used:

polyethylene;
polypropylene.

Fabrics reinforced with a special mesh can be perforated. You can also use non-perforated film, leaving gaps when laying. The reinforced film has a metallized surface. The film is laid down with a metallized surface to reflect heat loss.

The layer, consisting of fibers, absorbs moisture, evaporating it then naturally. The materials are durable and UV resistant.

There are also other vapor barrier materials that can be used when equipping an attic floor on wooden beams with a vapor barrier. These are varnishes and mastics, asphalt, bitumen, bitumen-cookersalt. Today, such materials are rarely used, preferring non-woven fabrics of synthetic origin. These are the so-called "breathing membranes", capable of passing moisture, air, multi-layer, single-layer, equipped with aluminum foil.

The material is laid with an overlap on the wall by 20 cm, fastened with a stapler, rough side down.

In modern construction of roof trusses, the very concept of a roof - the upper outer part of the structure - has been replaced by a roofing pie - the alternation of several layers of materials, each of which performs a specific function.

The sequence and technology of laying the roofing cake depends on the features of the top coating (for example, metal tiles) and the specifics of the room located under the roof: whether it will be a cold attic or a warm attic.

Depending on whether they plan to equip a warm or unheated room under the roof, the sequence of laying materials and the number of elements in the roofing pie will be different.

Cold attic without insulation

The waterproofing film or membrane is laid from the bottom up directly on the rafters. It is fixed on them with counter-lattice bars. The thickness of the bars is at least 2 cm - to provide a ventilated space between the film and the finish coat. Perpendicular to the bars of the counter-lattice, batten boards are mounted, to which sheets of metal tiles are attached.

Between the waterproofing film and the metal tile, a ventilation gap is required, which is equal to the thickness of the counter-lattice bar. Failure to comply with this point will lead to premature corrosion of the metal and a decrease in the service life of the coating.

Insulated attic

Unlike the cold version, the number of layers in the attic roof increases due to vapor barrier and insulation. The peculiarity of such a cake is the correct observance of the technology of laying materials - their sequence and the provision of ventilated gaps between them.

vapor barrier;
rafters;
insulation over the vapor barrier between the rafters;
waterproofing;
counterlattice;
crate;
metal tile.

Mounting sequence

The vapor barrier film is attached to the rafters with an overlap of at least 10 mm. It is important to ensure hermetic joining of the seams and places where the film adheres to the roof elements. If the manufacturer provides for the presence of a smooth and rough side in the material, then the smooth surface is laid against the insulation.

Insulation - most often it is basalt mineral wool or a fiberglass-based product - is installed above the vapor barrier. Mineral wool holds tightly between the rafters when cut 1–2 cm wider than the spacing between the rafters.

A sufficient layer height is 150 or 200 mm. Depending on the thickness of the material (it happens to be 50, 100, 150 mm), it is laid in several layers, so that the first layer overlaps the joints of the second. This helps to avoid the occurrence of "cold bridges".

Diffusion membranes can be laid directly on the insulation, while waterproofing films require an air gap (at least 3 cm). It provides air movement and drying of mineral wool from moisture, which partially penetrates through imperfect vapor barrier seams.

Above the waterproofing film, bars of the counter-lattice are installed; they will provide an air corridor (4–5 cm) between the film and the metal tile.

With temperature fluctuations (for example, it is hot during the day - it is cold at night), condensate forms on the inside of the metal tile, which flows down along the waterproofing film without falling on the insulation. For complete drying of this moisture, a ventilated space is needed. Read more in this article.

A crate is attached to the counter-lattice: the distance between the boards is 350 mm equal to the wavelength of the metal tile, the installation of which completes the entire roofing pie.

The roof must reliably protect the house from water, wind, temperature changes and, in fact, is the fifth wall, the design of which is a little more complicated than the others.

Non-compliance with technology, errors in construction and alterations result in an unnecessary waste of time, money and health, which is why it is so important to have a correct understanding of the features of roof structures.

Roof device with a cold attic

Most pitched roofs in our country have a cold attic in their design. This name is due to the air temperature in the attic, which should not differ much from the air temperature outside the house. With such an arrangement of the attic, a sufficiently large buffer air zone is formed, which allows you to effectively control the temperature in the attic with its proper arrangement.

Cold loft design

Cold loft roofs have the following main ingredients in their pie:

roofing;
attic outer walls (applicable for gabled roofs with gables);
insulated ceiling between living space and attic.

Dormer windows are located on opposite roof slopes so that there are no unventilated areas.

Steam and thermal insulation of a cold attic

The following types of heat insulators are often used in ceiling ceilings:

polystyrene and foam boards;
mineral wool boards or mats;
expanded clay granules;
fuel or granulated slag;
sawdust with lime or clay;
pumice.

The thickness of the required insulation layer is selected depending on the calculated winter temperature using the table below.

Winter temperature is calculated according to SNiP 2.01.01-82 (construction climatology and geophysics) or is selected by regions of the Russian Federation from the corresponding climate maps.

Insulation is placed between the joists or beams of the ceiling, and a plank flooring is made on top for attic passages. Logs are usually 50 mm thick, and deck boards are 25-35 mm thick.

For ventilated attic spaces, soft or semi-solid heat-insulating materials are considered the most optimal.

Attic waterproofing device

Possible leaks or condensate when it gets into hydrophobic heaters significantly reduce their heat-insulating properties.

Temperature regime of a cold attic

You can evaluate the effectiveness of a heat insulator using a temperature measurement of the top layer of insulation. An electronic thermometer is immersed in a heater by 10-20 mm.

Cold attic: ceiling pie, device, ceiling vapor barrier and waterproofing

The device and design of the cold attic pie. Vapor barrier ceiling and waterproofing in a cold attic. The optimal temperature for the attic.

Roofing cake for a cold attic

Roofing cake for a cold attic can be divided into two parts. The first part is on the floor between the attic and the living quarters. The second part is on the slope.

The first part of the roofing pie, depending on the type of flooring, looks like this:

The insulation is laid in several layers with a spacing of joints to eliminate cold bridges.

The second part of the roofing pie using flexible tiles in a cold attic looks like this:

Mansard roof pie device with insulation

Outwardly, it is impossible to distinguish a house with a pitched roof, under which an attic is equipped, from buildings with an attic, except perhaps by the dormer windows. But if you delve into the design of the roof, you can find significant differences. Attic spaces are insulated only from the side of the ceiling, so as not to release warm air from the residential floor. The mansard roof cake contains many layers that allow you to create a microclimate favorable for living in the space under the roof.

Design features

First, let's figure out what is called a roofing pie. These are the necessary structural layers of the roof, which are laid in a certain sequence and are needed to insulate the structure, protect against condensation and moisture from the street, and also as a base for laying the roof itself.

The roofing cake of a cold attic and a warm attic is significantly different. In the first case, fewer structural layers are used. Usually this is rafters, waterproofing, lathing and roofing. When arranging residential attic spaces under a roof, the correct roofing pie consists of the following layers, arranged from bottom to top:

interior decoration of the premises;
vapor barrier layer;
rafter system and heat-insulating material, which is laid between the rafters;
waterproofing carpet;
clearance for ventilation of the under-roof space (it is formed by laying the counter-rail);
crate;
roof covering, namely the selected roofing material.

Each of the listed layers performs its own specific functions, so the absence of a layer or its improper installation can lead to large heat losses and significant costs for heating a house. Due to the accumulation of condensate, the insulation can become damp, and the supporting structures of the rafter system are quickly destroyed.

Important! It is worth remembering that not only the presence of a certain layer and its correct installation is of great importance, but also the choice of a suitable material in accordance with the features of the roof structure and the climatic conditions of the construction region.

Features of each layer

Next, we will consider the attic pie in layers, indicating the design features, as well as the nuances of the selection and installation of materials. We will consider all layers of the mansard roof structure, moving from the room to the outside.

The very first layer, which is located on the side of the room, is the interior decoration. For these purposes, you can use drywall sheets, plastic panels, wooden lining and other finishes. Among all materials for finishing the attic, drywall and wood have an advantage, since they can naturally regulate the humidity in the room, which contributes to a favorable microclimate.

vapor barrier

The vapor barrier layer is attached to the rafter system from below. It is needed to protect the internal structures of the roof and insulation from the formation of condensate due to the temperature difference between indoors and outdoors.

Attention! The absence or poor-quality vapor barrier leads to the accumulation of condensate moisture in the insulation. Due to dampness, the insulation cannot perform its heat-insulating functions, and it will be cold in the room.

Vapor barrier roll materials are rolled across the direction of the rafters and attached to them using a construction stapler. In this case, it is necessary to overlap the strips by 150 mm. The joints of the strips of material are additionally sealed with special tapes or ordinary adhesive tape.

The following materials are used as vapor barrier:

The most affordable and inexpensive vapor barrier is glassine. Over the years, its properties to protect against condensate moisture decrease, so it is better not to use it.
Special vapor barrier membrane. This is a polyethylene film, which may have additional reinforcing and reflective layers. She does her job well and does not sag.
Foil vapor barrier. This is the most expensive material, but in addition to protecting against moisture, it allows you to effectively retain heat in the room due to the reflective layer. The foil film must be fixed with a gap of 10-20 mm from the insulation. To obtain this gap, before fixing the film, slats of the appropriate thickness are stuffed onto the rafters.

Worth knowing: the vapor barrier should not fit snugly against the insulation laid between the rafters, so the material is attached to the rafters with a slight sag (about 2 mm).

truss system

For the manufacture of pitched roof rafters in a private house, elements made of coniferous wood of at least grade 1 with a moisture content of not more than 15% are used. The optimal section of the rafters is 150x50 mm. In the middle climatic zone of our country, for effective insulation of a mansard roof, it is necessary to use heat-insulating material with a thickness of 200 mm. As you can see, the height of the rafters of 15 cm will not be enough, so a bar with a section of 50x50 mm can be attached to them from below.

The installation step of the truss system depends on the roof structure, the width of the heat-insulating material used and the type of roofing. It is also worth remembering that the larger the step of the truss system, the larger the cross section of one element should be. For rafters with a section of 5x15 cm, the optimal pitch is 800-900 mm.

Important! All wooden elements of the supporting frame of the roof must be protected from rotting and burning. To do this, they are pre-treated with antiseptics and fire retardants.

insulation

The most important thing in the design of the attic roof is the insulation pie, because the comfort of living in the attic, as well as the level of sound insulation of the premises, depends on it. For thermal insulation of pitched structures, they usually use:

Mineral plates. They are made on the basis of basalt fiber, they are quite dense, non-flammable and retain heat well.
Fiberglass is a non-flammable, environmentally friendly material. Its disadvantage is the instability of the structure and the possibility of sagging.
Styrofoam is an inexpensive, efficient material that does not absorb moisture at all, but releases toxic compounds when burned.
Expanded polystyrene is a very light, non-flammable and non-toxic material that does not accumulate moisture. However, it has increased vapor permeability, so in summer there may be high humidity on the attic floor. Due to its high rigidity, expanded polystyrene is difficult to lay on difficult sections of the roof.

Tip: to insulate the attic, it is better to use soft mineral wool slabs based on basalt. They are easily mounted in difficult areas and fit snugly to the rafters without the formation of cold bridges.

For each construction region, the thickness of the heat-insulating material is calculated individually. The minimum layer of insulation is 150 mm. For regions with severe winters, it is necessary to use a heat-insulating material with a minimum thickness of 20 cm. In this case, the insulation is laid only on dry wood of the rafters. Otherwise, moisture will penetrate into the thermal insulation material and reduce its effectiveness.

Waterproofing

The main purpose of waterproofing is to protect the insulation from moisture penetrating from the roof, as well as the ability to pass water vapor, which will evaporate from the heat-insulating material. That is why a vapor barrier film is not suitable for these purposes, because it does not allow water vapor to pass through. For roof waterproofing, special materials are used:

diffusion membranes. These are films with microscopic funnel-shaped holes. The material is laid in such a way that the wide part of the funnel is turned towards the insulation, and the narrow part towards the roofing. In this case, it is necessary to create two ventilation gaps and lay the material from the insulation at a short distance so that the funnels are not clogged with water vapor. These membranes can only be used with roof coverings that are not afraid of moisture that collects from the back.
superdiffusion membranes. The effectiveness of this material does not require the arrangement of an air gap on the side of the insulation. Such films are suitable for houses where the roof is laid in an already inhabited building. The membranes protect well from the wind.

Important! Both types of membranes cannot be used with euroslate and metal tile coatings, since their back side must be reliably protected from condensate. But for coverings from soft and traditional tiles, these membranes are ideal.

Condensate films are used for roofing made of euroslate and metal tiles, since they do not allow water vapor to pass through. In this case, excess moisture from the heat-insulating material accumulates on the fleecy side and is brought out through the ventilation gap. In such structures, it is necessary to provide a second ventilation gap between the waterproofing carpet and the coating so that condensate does not accumulate on the back of the roof.

Counter rail and crate

If it is necessary to equip the ventilation of the under-roof space, then the slats of the counter-lattice are stuffed over the waterproofing carpet. To do this, use a beam with a section height of 30-40 mm, which is nailed in the direction of the rafters.

Next comes a layer of framing. It can be continuous or sparse. The first option is equipped for soft roofing, for example, flexible tiles, and is made of OSB or moisture-resistant plywood. Between the elements of a continuous crate, it is necessary to leave a deformation gap of 2-3 mm. In the second case, boards 25 mm thick are used, which are nailed across the rafters in increments of 30-40 cm. After that, the roofing is laid.

Mansard roof pie and proper roof insulation

Design features of the mansard roof pie and description of the layers. Rafter system, vapor barrier, waterproofing and insulation. Counter rail and crate.

How to arrange a roofing pie under a soft roof: general principles and analysis of construction options

Types of soft roof structures

The standard structure of a roofing pie includes the following mandatory components:

Vapor barrier. Prevents the penetration of evaporation from the interior of the house and the condensation of moisture on the building materials used in the construction of the roof;
Thermal insulation. Contributes to the preservation of heat, protects from noise coming from outside, winds, cold temperatures;
Waterproofing. Prevents the penetration of rainwater and melted winter precipitation into both the roof structure and the building;
decorative coating, which simultaneously performs the work of wind protection.

the type and purpose of the object being equipped, i.e. a residential building or household building;
temporary or permanent use, determining the use or rejection of thermal insulation;
the shape of the roof and the steepness of its slopes, directly related to the choice of materials for roofing;
type of base for arranging a pie and laying a soft roof;
the presence of an operated or non-operated attic;
regional climatic features, according to which the thickness of thermal insulation is determined;
compatibility of structural layers, as in case of incompatibility, separation or migration layers will be required.

The principles of the roofing pie

Roofing cake for flexible tiles

The simplest non-insulated option

The scheme for laying a soft roof over an uninsulated attic is extremely simple:

a counter-beam installed across the rafters is nailed to the rafter legs. The recommended size of the bar is 50 × 50, it is attached with two nailed nails to each rafter. The installation step of the counter beam depends on the step between the rafters. If the distance is standard 0.7-0.9 m, the bar is nailed after 30 cm;
slabs of a continuous crate are laid on a counter beam in a run-up so that there are no cruciform joints between them. The edges of the slabs must rest on the elements of the counter-lattice. The plates are fixed after 15 cm with nailed nails to the bar;
a self-adhesive waterproofing carpet is laid, the laying of which is carried out depending on the steepness of the slopes. At a slope of 18º or more, only slopes, ridges, valleys, junction areas and pipe passages through the roof are covered with waterproofing. Less steep roofs are completely covered with an insulating carpet;
a soft tile is mounted on top of the waterproofing barrier.

Insulated roof device

The scheme for laying layers of a roofing cake for an insulated pitched roof, which involves the operation of an attic, is as follows:

on the inside of the rafter system, a vapor barrier membrane is attached directly to the rafters with a stapler. It is laid parallel to the overhangs in strips from the bottom up. In a single canvas, the strips are connected with double-sided tape;
according to the arranged vapor barrier, again from the inside, a counter-lattice is constructed from a bar, the installation step of which depends on the material of the planned inner lining of the attic. For example, under plasterboard sheathing, it is desirable to place the lathing bars at a distance of 40 or 60 cm;
auxiliary struts are mounted on the outside of the roof between the rafters. They are required to hold the insulation boards. Spacers are placed in increments of 2-3 cm less than the height of the heat-insulating plate. So it is necessary that the thermal insulation is rigidly fixed in the compartments created for it, “straightened out” after light compression during the installation process;
in the resulting semblance of honeycombs, a heat-insulating material is placed, the thickness of which should be 3-5 cm less than the thickness of the rafter legs. This is a necessary condition for proper ventilation of the roofing cake;
the counter-lattice is being built again. It is nailed to the rafter legs along their direction in order to form ventilation ducts - roofing vents;
a solid crate is attached to the outer counter-lattice, on top of which an additional waterproofing carpet is laid;
soft tiles are laid.

The stages and principles of arranging a roofing pie for soft tiles will be presented by a video:

Roofing cake for roll materials

Principles of a vapor barrier device

The vapor barrier layer for laying rolled materials are materials such as:

bituminous and bitumen-polymer vapor barrier welded onto a concrete or cement-sand base, including cement-sand insulation with vermiculite, expanded clay, perlite in the form of filler in case of a slope slope of more than 6º. If the slope is less, the bituminous vapor barrier can be laid without gluing or fusing to the substrate.;
polyethylene reinforced or non-reinforced vapor barrier, laid freely along the corrugations of a profiled sheet or glued to it in case of slopes of more than 6º.

Rules for laying thermal insulation

The device for thermal insulation under the roll coating requires compliance with the following rules:

heat-insulating material is attached separately from the coating laid on top;
with a mechanical method of fastening, each thermal insulation plate and its separate part is fixed at two points. The insulation is fastened to the profiled sheet with steel self-tapping screws with a plastic sleeve in the form of a fungus. Plastic bushings are not used if the ramp slope is greater than 10º. In any case, they are attached to the concrete base with self-tapping screws with dowels and metal plates;
gluing of insulation boards is carried out on bitumen-polymer mastic. Bonding is possible if the area “planted” on the adhesive composition of the surface is at least 30% of the area of the insulation board;
insulation boards are laid with a mandatory expansion of the seams so that the weak areas are distributed evenly. The elements of the second tier, if any, are displaced relative to the first by at least 20 cm, both along the side and end lines;
seams in the insulation mat with a width of more than 5 mm must be filled with heat-insulating material.

The use of rigid insulation is justified economically and technologically. It allows you not to arrange a screed on top of the insulation, which is mandatory for backfill thermal insulation.

Additional layers of roofing material

The construction of the roofing pie is completed by laying the rolled coating and fixing it by fusing, gluing or fastening with self-tapping screws with bushings or plates.

Roofing cake for a soft roof: general principles of the device from the pros

A well-arranged roofing pie under a soft roof will provide a normal microclimate inside the house, guarantee a long service life of the structure, and save you from repairs.

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