How to insulate the roof of a house. And severe frost is not scary: how to insulate a roof with your own hands
Do-it-yourself roof insulation in a private house is a responsible and complex undertaking.
But, knowing the basic requirements and techniques for working with roofing materials, completing the task will not be difficult and will save significant money.
Preparation for insulating the roof of a private house largely depends on the design of the existing roof. If additional thermal insulation of an existing flat roof is required, you need to find out the condition of the roofing pie; for this, a pit measuring 1x1 m is selected, and the condition of the insulation is assessed.
When in working condition, it is possible to install insulation over the existing carpet, however, this method increases the load on the supporting structures and is not always feasible. If the insulation is locked or destroyed, the existing roof is dismantled and a new pie is laid.
To ensure the quality of thermal insulation of a pitched roof, the following work must be performed before insulation:
- Check the serviceability of the waterproofing layer and repair if necessary.
- Check the condition of the drainage system.
- Coat wooden structures with a fire retardant and fungicidal composition.
Choice of materials and design
How to insulate the roof of a private house? The insulation market is saturated with a variety of materials, which makes choosing difficult. To insulate a residential building with your own hands, it is advisable to select a material based on two criteria: fire resistance and thermal conductivity. That is, the material must be safe and effective.
Insulation materials
The most commonly used extruded polystyrene foam and polystyrene foam are effective, but flammable, so they cannot be recommended for insulating housing, especially with wooden roof structures.
Non-flammable materials include slabs and mats based on stone, basalt and mineral wool, foam glass and flax slabs.
Their thermal conductivity coefficient is approximately the same from 0.042 to 0.047, but their cost and service life are different. The greatest durability is guaranteed by manufacturers of flax slabs - from 60 years and above, but their cost is also above average, followed by basalt slabs. The remaining insulation materials occupy the same price niche.
Calculation of the insulation thickness using a simplified scheme can be carried out using the formula:
δ = R x λ
In this formula:
δ
– calculated size, meters;
R– standard thermal resistance;
λ
– thermal conductivity coefficient of the insulation used.
The standard thermal resistance depends on the climatic zone of construction:
The thermal conductivity coefficient of Rockwool stone wool mats is 0.038 with a volumetric weight of 35 kg/m3. We calculate for Moscow:
δ = 4.67Х0.038=0.17746 m,
that is, to insulate the roof slope of a house in the Moscow region, the required insulation thickness is 180 mm.
How to insulate the roof of a private house? The choice of materials also depends on the roof design. Flat roofs and pitched roofs require different materials. We will consider each option.
Insulation of a flat roof
The composition of the roofing pie for a flat roof looks like this:
- Waterproof carpet.
- Insulation.
- Vapor barrier.
- Screed to create a slope.
- Cover plate.
As a waterproofing carpet, 4 layers of rolled fused bitumen-polymer material, for example Technoelast, Krovlyelast, are laid. The top layer should have a protective coating of stone chips.
IMPORTANT: Fusing is carried out using a hair dryer, without the use of an open flame.It is possible to perform a membrane roof with mechanical fastening to the slab. The membrane is laid in 2 layers, but the cost of such a cake is much higher.
It is advisable to use non-flammable insulation from materials of mineral origin - basalt, mineral, glass wool. The insulation is laid in 2 layers: below - soft mats, on top - slab material that can withstand periodic human walking without losing its shape.
PLEASE ATTENTION: It is possible to insulate the roof of a private house with polystyrene foam, but since this insulation is flammable, it is advisable to lay a 15 mm thick screed of light, fine-grained concrete on top of it to prevent possible contact with fire.Vapor barrier - a layer of geotextile prevents water vapor from entering the insulation from the room.
The screed for creating a slope is also made of light, fine-grained concrete, its height depends on the length of the slope, the minimum thickness is 10 mm, the angle of inclination is 1.5%.
The covering slab in low-rise housing construction is usually made of lightweight concrete, but it is also possible to find monolithic reinforced concrete on a metal profiled flooring.
Insulation of pitched roofs
Let's look at ways to insulate the pitched roof of a private house. This can be done in two ways:
- Option 1 – insulation of the attic floor, in this case the attic remains cold;
- Option 2 – insulation of the roof slope, in this case the owners have additional living space at their disposal.
Option 1
Insulation is the simplest and least expensive: in this case, you can use the most budget-friendly bulk insulation - expanded clay, as well as slag. Geotextiles or any other material with similar properties are laid over the ceiling, a layer of insulation is poured on top of it, and a lightweight concrete screed is placed on top of it. To make it possible to walk around the attic, walkable flooring is laid.
The thermal conductivity coefficient of slag is significantly greater than that of modern insulation materials, which means that the layer thickness will be greater and the load on the floor will be higher. If the ceiling is made of wooden beams and it is necessary to reduce the load on them, it is better to insulate the attic floor with mineral or stone wool.
First, a vapor barrier is laid, fastened with a stapler to the rafters. The canvases are mounted with an overlap of 10 cm, the edges are sealed with tape. Insulation mats are placed in the spacer between the beams. Then another layer of vapor barrier film is placed, and on top of it is a flooring made of moisture-resistant chipboard or other boards.
Option 2
Repeats the insulation of floors with mineral wool: a layer of vapor barrier material is laid between the coating material and the insulation, then insulation is installed between the rafter structure, which is protected from condensation from the premises by another layer of vapor barrier film; to create a flat surface, the slope is covered with board material: chipboard, fibreboard, OSB.
As you can see, to create a high-quality insulating layer, you need not only insulation, but also non-woven materials to protect the heat insulator itself - a vapor barrier membrane on the outside and a vapor barrier layer on the inside. Carrying out work using the above technology guarantees the durability and reliability of the structure, and improves the microclimate of your home.
Heat loss in the cold season, 15–20% of total heat loss reaches through the roof.
This means that if the floor and walls are well insulated, but the ceiling or roof is not insulated, then with total heating consumption 2000 kg of coal per season, 300–400 kg is spent on heating the street.
Thus, with an insulated roof, it will be possible to buy 1600–1700 kg of coal per season instead of two tons.
However, the matter is not limited to saving money. Roof without thermal insulation heated by warm air from below. Snow falling on a warm roof melts and sticks to it in a thick layer. This increases the stress on the roofing material and can lead to damage. During a thaw, a layer of snow melts from below and slides off the pitched roof, damaging the drainage system.
Roof with good thermal insulation stays cold. Dry snow is blown away from it by the wind, practically without stopping. There are almost no icicles on the edges of such a roof.
Obviously, the difference is significant enough to consider insulating the roof. This kind of work does not require high qualifications, so with certain knowledge and skills you can do it yourself.
You can insulate the roof from heat from below during its installation. This is what they usually do now. Work in this case are carried out from above in this order:
- A vapor barrier membrane is attached to the lower surfaces of the rafters. To do this, the panels are unfolded and, slightly stretched, stapled with a stapler. Work begins at the bottom of the rafters and ends at the ridge. The panels overlap at the joints, gluing the edges with construction tape.
- From below, the vapor barrier film is nailed to the rafters with bars with a cross-section of 30×40 mm across the rafters in increments of 30–40 cm. This lathing will hold the insulation, and the finishing material is attached to it from below.
- Insulation boards are laid on top between the rafters to the level of the top edge.
- When the slabs of heat-insulating material are level with the upper edge of the rafters, they are covered with panels of waterproofing, vapor-permeable material. This hydrobarrier is secured with staples using a stapler in the same way as a vapor barrier with an overlap of 15 cm.
- A sheathing is constructed on top of the hydrobarrier, onto which the roofing material is secured.
However, for one reason or another, insulating materials are not always installed together with the roof. In this case the roof have to insulate later. The same is done in old houses after renovation.
Do-it-yourself insulation of a finished roof in a private house
Laying thermal insulation into an already constructed roof happens in reverse order. If the insulation “pie” during construction is formed from above, then the finished roof is insulated from below.
Before work starts need to find out how well the roof is installed.
In an old house need to check strength of rafters and floor beams. Rotten load-bearing elements are replaced with new ones, treated with preparations that protect against rotting and fire. After this, they begin laying thermal insulation:
- After measuring the thickness of the rafters and the distance between them, the sheets of thermal insulation material are cut with a slight excess in width (about 1–2 cm). This is necessary so that the elastic plates fit into place tightly, without gaps.
- A hydraulic barrier is needed between the roof and the insulation, protecting against water drops but allowing steam to pass through. If the roof is new and was installed according to all the rules, you will not have to lay it. Otherwise, you will have to purchase waterproofing. The best candidates for this role are the so-called superdiffusion membranes, do not allow liquid water to pass through, but at high air humidity they allow water vapor to pass through. This material is laid without undue tension and secured with a stapler to the rafters, and in the spaces between them - to the roof sheathing. The panels at the joints are secured with an overlap of 15 cm, gluing one panel to another with construction tape.
- Cut slabs of thermal insulation material are inserted between the rafters, pressing them against the membrane. All cracks that arise are sealed with construction foam. It is preferable to lay the slabs in two layers, overlapping the joint of the previous layer with the slab of the next one. After completing this stage, the level of the slabs should be equal to the inner end of the rafters.
- Along the inner end of the rafters it is stretched and secured with a stapler. The panels are unfolded horizontally and laid from bottom to top with overlapping edges of adjacent panels 15 cm wide. The edges are glued with construction tape.
- On top of the film, at right angles to the rafters, sheathing bars with a cross-section of 30×40 mm are stuffed in increments of 30–40 cm. The lining or fiberboard slabs will be attached to them. After completion of the work, a ventilation gap is formed between the vapor barrier film and the finishing to evaporate possible condensation.
- The more carefully the vapor barrier is laid, the better the insulation retains heat.
Flat roof insulation
Flat roof too can be insulated. However, in this case there is no attic. External insulation of such a roof is done during the process of laying the roof. A vapor barrier film is glued to the floor slab.
Insulation is laid on top of this film. The best thing suitable for these purposes. After laying, the top of the stone wool is covered with roofing felt, which serves as a vapor-permeable waterproofing.
So that you can walk on the roof, without damaging the roofing material, the covering is done in the same way as on the sidewalk. To do this, a layer of expanded clay is poured onto the roofing material, then a cement-sand mixture, on which paving slabs are laid. After getting wet in the rain, the cement-sand mixture sets and holds the tile.
Expanded clay underneath plays the role of drainage. There are no ventilation layers in such a roof. Internal insulation of a flat roof is done using the technology of internal thermal insulation of the ceiling.
So that living conditions in winter are quite comfortable, it is necessary to ensure a certain level of thermal insulation of the room. This level is determined by heat transfer resistance. It does not matter how many layers and what kind of heat-insulating material are laid.
You can read about how to calculate the required insulation thickness in the article “”. If you correctly lay thermal insulation materials when installing the roof, you can save 15–20% energy, spent on heating a private house.
The technology of roof insulation is simple. Any home handyman can handle it subject to technology. You can insulate the roof during the installation of the roof and after it. However, the technology for carrying out such work will be different.
For detailed instructions from ISOVER on how to insulate a roof in a private house with your own hands, watch the video:
To understand how to insulate the roof of a house, you need to know how it is structured, the features of its design and operation. For flat roofs alone, the domestic company TechnoNikol offers almost forty schemes of technical solutions. There are fewer such solutions for a pitched roof, but there are different options here too. And if you consider that this company is not the only one that produces roofing materials, and each other has its own established schemes, then a non-professional may get confused. But regardless of the technical nuances and characteristics of the materials, the principles of roof insulation are general.
Principles of insulation
There are two broad classes of roof construction: flat and pitched (or attic). And if we talk about functions, then there are also two of them: protection from atmospheric phenomena and thermal insulation.
In a flat roof, both functions are combined in one “pie”, which has the following arrangement of layers: ceiling, thermal insulation, roofing.
Insulation of a pitched roof can have three fundamentally different options:
cold attic with insulated ceiling;
exploited or a residential attic with an insulated roof:
combined roof with a warm contour of a dedicated attic.
But regardless of the design and location of the thermal insulation, all schemes have a common fundamental rule on how to properly insulate the roof of a house - on the side of the warm room, the insulation must be covered with a continuous and unbroken layer of vapor barrier materials. And the design itself must ensure the weathering of moisture from the insulation.
There are two main reasons for protecting insulation from getting wet - loss of thermal insulation properties and increase in the weight of the roofing cake. And if the loss of thermal insulation properties, apart from discomfort, does not threaten anything serious, then an excessive increase in the load on the supporting structure of the roof can lead to its collapse. In addition, vapor barrier in a pitched roof protects wooden structural elements from rotting and loss of load-bearing properties.
Insulation of a flat roof
The technology for insulating a flat roof depends on the floor materials and operating conditions.
Insulation of a flat wooden roof
Typically, flat wooden roofs are considered a “sign” of a frame house. This is precisely the scope of application that is indicated even in the “proprietary” description of roofing systems of companies producing thermal and waterproofing materials TechnoNikol. But even in brick houses, a wooden flat roof is not uncommon, since with a relatively light weight of the structure, it is possible to ensure sufficient rigidity and strength of the roof of a low-rise building.
The insulation scheme looks like this:
Base. Moisture-resistant OSB board (class 3 or 4).
Vapor barrier film. Spread the strips overlapping by 15-20 cm on the long side and on the short side (when increasing in length). Along the perimeter, the vapor barrier should rise to the parapet and adjacent surfaces by the same 15-20 cm. Polymer-bitumen vapor barrier films are attached to the base using glue or telescopic fasteners (together with thermal insulation). Polypropylene or polyethylene film can be spread without attaching to the base, fixing it around the perimeter to the walls of adjacent surfaces using self-adhesive vapor-tight tape.
Insulation for the roof of a house. Three types of materials can be used for thermal insulation of a flat roof: stone wool mats, extruded polystyrene foam, and rigid polyisocyanurate foam boards.
Roof covering.
Perhaps the most common example of a flat insulated roof over a wooden floor is a terrace with access from the second floor. But in this case, the design of the roofing pie is closer in structure to the insulated ceiling of a cold attic.
On our website you can find contacts of construction companies that offer roof repair services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
As a roof covering for flat roofs, roll waterproofing materials are used, which make it possible to create a continuous and unbroken top layer. But, as with the insulation of a pitched roof, the waterproofing layer must be “breathable”. There are two main options for installing a breathable flat roof:
application polymer membranes with high mechanical strength and resistance to direct exposure to ultraviolet radiation;
two-layer bitumen coating– fused rolled insulation on top, a substrate with ventilated channels on the bottom (for example, Uniflex Vent).
The advantage of a wooden flat roof is that a slight slope is created due to the position of the floor beams. And it is needed even on a flat roof to drain precipitation into the drain.
Insulation of a flat roof over a concrete floor
This type of insulated flat roof accounts for the most options for constructing a roofing pie.
To begin with, there are unused and used flat roofs. Moreover, “exploitation” can be of a completely different nature - from a terrace as a recreation area to the arrangement of a so-called “green roof”.
If we do not take into account the different options for roofing, then on a concrete floor the same sequence of layers is used as on a wooden one, except for one nuance - organizing a slope to drain precipitation into an external or internal drainage system. And here several solutions can be used:
device for covering screeds with a slope;
installation of a bulk slope-forming layer of expanded clay on the concrete base, separated from the insulated roofing pie by a reinforced screed;
installation of a bulk slope-forming layer of expanded clay over a layer of extruded polystyrene foam or mineral wool, followed by laying screed and roofing;
installation of a slope-forming layer from special slabs or thermal insulation mats, in which one surface is located in relation to the other with a slope.
Insulation of a pitched roof with a cold attic
Insulation of a pitched roof with a cold attic occurs along the ceiling. And depending on the flooring material, the patterns differ slightly.
Insulation of concrete attic floors
The layout of the layers is partially reminiscent of the insulation of the floor of the first floor:
A layer of vapor barrier is spread over the ceiling (overlapping strips, with gluing of joints and abutments to the enclosing surfaces).
Install logs (lathing) for laying the heat-insulating layer.
Lay thermal insulation. Typically, non-combustible materials are used as thermal insulation for the roof of a house - stone wool mats or loose expanded clay.
Lay a layer of waterproofing with high vapor permeability. According to the standard, laying a strip 1 m wide from the line of intersection of the ceiling with the external walls is required. When insulating the attic floor of a private house, the procedure is simpler - lay a waterproofing membrane over the entire area.
A spacer strip is attached along the joists (needed for a ventilated gap).
Installing the attic floor.
Insulation of the wooden floor of a cold attic
The insulation scheme for a wooden floor differs fundamentally in the location of the vapor barrier. The vapor-proof film is not attached to the floor beams from above, but is hemmed from below.
Video description
How to properly make hydro- and vapor barrier insulation of a cold attic floor, see the following video:
If you do the opposite, then water vapor from warm air will penetrate into the pores of the wood, but will not be able to erode - there is a vapor-proof barrier on top. This will lead to wetness of the wooden elements of the supporting structure, and no treatment with antiseptics will save the wood from waterlogging and rotting.
The scheme for insulating the wooden floor of a cold attic looks like this:
On the side of the room there is a vapor barrier, on top of which there is lathing for decorative finishing of the ceiling. Vapor barrier can be of several types: simple film, with an anti-condensation surface, with a reflective (reflective) surface. In addition to protecting the thermal insulation from getting wet, it protects the room from insulation particles getting inside.
Thermal insulation between beams is stone wool mats or expanded clay.
A layer of waterproofing superdiffusion membrane.
Distance bar.
Attic flooring.
Insulation of pitched roofs
This type of insulation of the roof of a house is used for arranging attics or if engineering equipment is installed in the attic (for example, a hydraulic accumulator, expansion tank, fan coil or ventilation system recuperator).
The standard roof insulation technology has the following scheme:
On the rafter legs, a waterproofing superdiffusion membrane is stuffed from bottom to top in overlapping strips. Vertical joints when extending the membrane in length must overlap and be on the rafters. Subsequently, the lower edge of the waterproofing is glued to the drip line (to drain condensate into the gutter).
On top of the waterproofing, a counter batten is nailed to the rafters, which provides a ventilation gap between the membrane and the roofing. To seal the fastening line, an elastic tape can be laid between the lath and the waterproofing.
Mineral wool mats are laid between the rafters.
A continuous layer of vapor barrier is attached to the inside of the rafter legs. If it has an anti-condensation or reflective surface, then it is turned towards the attic.
Place a spacer strip on top of the vapor barrier. It is necessary for the “correct” functioning of the anti-condensation or reflective layer. The second purpose of the slats is lathing for the interior lining of the attic.
A combined insulation scheme is used to highlight the “warm contour” of the attic. The principle of this scheme is to insulate the vertical fences inside the attic and only that part of the roof that is adjacent to the attic.
Video description
The following video is a demonstration of insulating an attic roof with two layers of stone wool:
Conclusion
Roof insulation is perhaps the most difficult type among all thermal insulation work on enclosing surfaces. Only a professional can understand the variety of schemes for different types of structures and materials. And the choice of insulation and the calculation of the thickness of the thermal insulation layer depend on the design. In addition, it is necessary to provide and arrange your own ventilation system for the roof and attic, without which the insulation will get wet and lose its properties, and the wooden structural elements will begin to rot.
In practice, roof insulation in private houses is carried out when it is planned to install a warm attic or residential attic. It is not customary to thermally insulate a cold roof; usually in this case, insulation is used to cover the ceiling between the attic and living space. Concrete flat roofs also need thermal insulation, since a huge amount of heat is lost through them. This article will tell you how to properly insulate wooden pitched roofs and concrete floors with your own hands.
Types of insulation for roofing
Nowadays, few people ask the question whether it is necessary to insulate the roof of a private house, since the answer is obvious. If you don’t want to overpay for heating, you’ll have to invest in thermal insulation. But how you can insulate the roof of your home, what material to choose for this purpose - this question interests many.
After all, the technology and sequence of work depends on the type of insulation chosen, which we will discuss further. So, at the moment, you can insulate a gable roof, including with your own hands, using the following materials:
- mineral wool in rolls based on fiberglass;
- mineral wool in slabs and rolls based on basalt fiber (stone wool);
- foamed polystyrene boards (foam plastic, extruded polystyrene foam, penoplex);
- sprayed polyurethane foam (PPU);
- foamed polyethylene with a layer of foil (penofol, isolon).
For reference. Not long ago, another new insulation material appeared on the modern market - ecowool, made from recycled waste paper and therefore characterized by a high degree of environmental friendliness. It’s just that using ecowool to insulate a roof, especially a pitched one, is very inconvenient, and it won’t be cheap.
The best insulation for the price is rolled mineral wool with fiberglass, offered by a well-known manufacturer - IZOVER. It protects the house quite well from the cold and can serve for a long time and successfully under one condition: the absence of moisture, its wool absorbs a lot and after that ceases to be a heat insulator. In addition, glass wool is not suitable if non-flammable insulation for the roof is required. The temperature limit of the material is 200 °C, upon reaching which it is destroyed.
The same brand IZOVER, and also URSA, produce non-flammable mineral wool from basalt fiber, suitable for insulating any pitched and soft roofs. She also likes to absorb moisture, but at the same time resists flame perfectly. It is very popular in the field of thermal insulation of roofs due to its affordable price; it is offered in rolls and slabs. The most famous manufacturer is the Polish brand ROCKWOOL.
Next come polymer insulation, whose properties are exactly the opposite - they repel water, but are flammable. Polystyrene foam is cheap, but still susceptible to slight vapor permeation, so during installation it is better to protect it with a vapor barrier. At the same time, expanded polystyrene and penoplex are practically impenetrable and do not require any protection, which simplifies the installation of roof insulation. And most importantly, all these materials have higher thermal insulation properties than any cotton wool.
Note. There is a lot of discussion about whether it is possible to insulate a roof with foam plastic and other flammable polymers. If we are talking about a private house, then no one will be fined for this, but you must understand that in this way you are increasing the fire danger for the building as a whole.
It will cost the most to insulate a roof with polyurethane foam, since it is impossible to do it yourself without specialized equipment. The technology of such thermal insulation consists of applying a layer of polyurethane foam to the surface, which grows in volume from 30 to 120 times. At the same time, polyurethane foam is the best insulation in all respects; it is not afraid of moisture and has the lowest thermal conductivity. It can also be called fireproof, because polyurethane does not immediately collapse when exposed to flame.
Materials made from foamed polyethylene have good thermal insulation properties, but due to their small thickness they can only be used together with other insulation materials. Thanks to the closed pores and the foil layer, the same penofol will serve instead of the inner layer of vapor barrier.
If we consider old traditional insulation materials, such as expanded clay or sawdust with clay, then it is quite difficult to insulate inclined roof slopes with their help. They are usually used for thermal insulation of the floor of a cold roof. Expanded clay or clay is used to fill the recesses between the floor joists in the attic, having previously laid a film.
Insulation calculation
There is nothing difficult in calculating the amount of thermal insulation material, knowing the insulated surface area of a pitched, flat or gable roof. In addition, the size of the insulation is most often tied to the standard interval between the roof rafters (600, 1000 mm). Another thing is to correctly determine its thickness, for which you will need to refer to the regulatory framework.
For each region, regulatory documents establish a minimum value for the heat transfer resistance (R) of roofing structures. That is, the thickness of the insulation should be such that it provides this value, no less. The table below shows the minimum thermal resistance indicators for some cities of the Russian Federation:
If we take Moscow and the region, then for this area the value of R should be no less than 4.67 m2 °C/W. Having adopted the most popular insulation - URSA mineral wool, we find out from publicly available sources its thermal conductivity coefficient λ, equal to 0.045 W/m2 °C. After this, we calculate the thickness of the thermal insulation layer:
In this formula:
- δ – desired thickness in meters;
- R – standard thermal resistance, equal to 4.67 m2 °C/W;
- λ – thermal conductivity coefficient of cotton wool, assumed to be 0.045 W/m2 °C.
Hence δ = 4.67 x 0.045 = 0.21 m = 210 mm. Since the correct solution is to take the thickness of the roof insulation with a margin, and not at the minimum, the final result of the calculation is 250 mm. For convenience, below is a diagram showing the thermal conductivity of various materials:
By the way, this calculation method does not take into account the resistance of the roofing due to its relatively small value. Any metal roof, such as metal tiles, does not retain heat at all. Slate, ceramic and bitumen tiles behave a little better, but compared to the required insulation layer, their resistance to heat loss is negligible.
Advice. When choosing a thermal insulation material, be sure to pay attention to its density; the degree of thermal conductivity depends on it. The greater the density of the insulation, the stronger the material, but also the higher its ability to transmit heat. This will ultimately affect the calculated insulation thickness.
Roof insulation technology
It should be noted here that it is most convenient to properly insulate a pitched roof from the inside during construction. But it is better to insulate a concrete slab from the outside by laying a layer of insulation under a soft roof, rather than then hemming the ceiling from the inside. The thermal insulation “pie” diagram for this option looks like this:
First, a waterproofing membrane is laid on the concrete base, and on top of it is slab insulation of sufficient density (for polystyrene foam this is 35 kg/m3, mineral wool - at least 125 kg/m3). Then a cement-sand screed 50 mm thick (minimum 30 mm) is placed on top. The last stage is laying the roofing material, usually roofing felt. The technology is described in more detail in the video:
The composition of the insulation pie for gable roofs of regular and broken construction depends on the material used. But 2 rules remain the same for all options:
- A diffusion membrane must be laid under the roofing. It does not allow water to pass through, but allows steam to escape;
- between any roofing covering and the membrane there must be a ventilation layer through which air circulates from the overhang to the ridge, as shown in the diagram:
Important. If there is no diffusion membrane on an old, cold roof, then to insulate it you will have to remove the metal tile or slate covering and lay waterproofing on the outside. It is not allowed to stretch the membrane along the rafters from the inside, since it will not be able to drain water to the street.
Insulation with mineral wool
So, before installing metal tiles or slate, a diffusion membrane should be laid, ensuring a tight fastening using counter-lattice bars. The canvases must be laid horizontally, starting from the bottom, to allow for the flow of water over them, with an overlap of at least 10 cm, as in the photo:
The next step is internal insulation, for which you need to cut mineral wool and insert it between the rafters. It is necessary that the size of the insulation in width be a couple of centimeters larger than the interval between the rafters. This will allow you to insert it tightly, the cotton wool will not fall out.
If the width of the rafters allows you to insert cotton wool of the calculated thickness, then next comes a layer of film for vapor barrier, which is nailed to the rafters with lathing strips for installing the interior finishing. The width of the strip is 4-5 cm, due to which an air gap will appear between the finish and the vapor barrier. The diagram of the entire “pie” for roof insulation is shown in the figure:
When the width of the rafter board is not enough, the whole assembly becomes somewhat more complicated. You will have to lay the wool in a second layer, for which you need to horizontally nail bars of the required width to the rafters. Insulation is laid between them in the same way, and then according to the previous algorithm.
Note. To insulate a pitched roof with mineral wool, the composition of the “pie” remains the same, only the work will have to be done while standing on a scaffold, as when insulating the ceiling.
Foam insulation
When thermally insulating a roof with foam plastic slabs, it is recommended to follow the same sequence of actions as when insulating with basalt wool. One clarification: the slabs need to be cut not by 2 cm more than the interval, but by a couple of millimeters, since the material is quite dense and durable. It also doesn’t hurt to protect the foam from the inside with a vapor barrier, since this insulation is destroyed by prolonged exposure to moisture.
Advice. Instead of a vapor barrier, a layer of foil foam can be laid on top of the foam. The sheets are laid end-to-end and glued with aluminum tape.
Another thing is extruded polystyrene foam or penoplex, which repel water vapor. It is not necessary to cover them with film, and the dense structure allows you to fasten the plates with self-tapping screws. When the width of the rafters is not enough, the second layer of penoplex is attached to them exactly as shown in detail in the video:
Conclusion
The complexity and duration of the roof insulation process largely depends on the thermal insulation and physical properties of the insulation. The eternal rule applies: cheap material must be laid in 2 layers and protected from vapors, which means more labor will have to be invested. Expensive insulation materials are attached much more conveniently and quickly. The least of your worries will come from insulation with polyurethane foam, which is very important for a broken roof structure, but it will also require a lot of money.
How to insulate a roof in a private or civil building using cheap roof insulation? This question is asked by many people. Indeed, a house without a high-quality insulated roof is inferior to the same one, but with insulation.
After all, up to 30% of heat can escape through the roof. Heat loss in an uninsulated house is so noticeable that some builders strongly recommend adding roof insulation as a working element at the design stage.
Insulation and insulation of pitched roofs
Now we will figure out how to insulate a roof with maximum efficiency, spending a minimum of effort.
Roof insulation is carried out very often. It is extremely necessary if you are going to live in a house, saving your resources and not wasting them on unnecessary heating.
There are two main types of roofing structures:
- Flat; pitched with insulation of the attic of a private house.
Flat roofing is characterized by the use of floor slabs as the main load-bearing elements and structures. Floor slabs are mounted directly on load-bearing walls. They are laid in almost the same way as conventional floors.
But the flat roof elements are the only barrier between the cold air outside and inside the room. It would seem, why does a concrete slab, which has quite an impressive thickness, need insulation?
And it needs insulation for the same reason as walls or foundations. Load-bearing structures made of concrete, no matter how strong and thick they are, still need insulation, since they tend to freeze and let cold air into the room.
They let it through in small quantities, but if the structure gets seriously cool, it itself will transfer the temperature inside the room, thereby cooling the air around it.
A pitched roof is built using SNiP. However, SNiP is also used in the construction of flat roofs. But the pitched one is different in that its design is much more flimsy.
A pitched roof with roof insulation using polyurethane foam consists of several wooden slopes that are supported on inclined rafters. The sheathing is placed on top of the slopes, and the finishing roofing layer is installed even higher. All work must be carried out in accordance with the standards specified by SNiP.
As you yourself understand, such a design is generally unable to effectively block cold air flows.
Insulation of pitched roofs with mineral wool
The salvation seems to be the arrangement of the attic. Indeed, a properly installed attic can become a barrier between the cold air outside and the microclimate inside.
But these are only half measures. If temperatures drop significantly, the attic will also freeze, followed by the ceilings. It is not surprising that the question of how to insulate a roof has become so popular in our time.
1.1What insulation materials are used for roofing?
Before you begin to understand the technology of how to properly insulate the roof of a house, you need to pay attention to the materials themselves from which the roof will be insulated.
Insulation can be done in different ways. However, over the past few decades, several of the most popular and effective solutions have emerged. They use modern thermal insulation from materials that are available on the market.
Most often, insulation is carried out using:
The use of mineral wool is almost always justified. This universal material has no restrictions, as it has all the necessary characteristics.
With its help, you can perform insulation both inside and outside the house. Although it is preferable to use mineral wool for finishing a pitched roof. The current SNiP also testifies to this.
If you look at SNiP more closely, you can understand that most mineral wool insulation materials do not have enough nominal density for finishing a flat roof. And let’s not forget that mineral wool is an expensive material.
The use of thermal insulation boards for flat roofing Roof Butts
Insulating large areas with it is not always productive and very expensive. However, there is basalt wool for flat roofs. Its most popular example is the Rockwool Roof Butts model for insulating an attic from the inside.
This type of mineral wool is specially compacted and treated with substances that allow it to be used outside the house as thermal insulation for a flat roof.
Moreover, the slabs there are marked using an interesting technology. Below, as a rule, base slabs are placed (they are thicker and softer), and so-called finishing slabs are mounted on top, which are characterized by increased density and complete hydrophobicity.
Expanded polystyrene is also in demand when it comes to roof insulation. But using it as insulation for stingrays is not the best solution. The main nuance here is that polystyrene foam is capable of burning, and even moreover, supporting combustion on its own.
But the pitched roof is made of wood. It is quite obvious that it is not recommended to insulate it with flammable material. However, the decision here is yours.
The risk is not always justified, but in fact, polystyrene foam really does a good job. Therefore, if you do not have money for other options, then you can turn to this one.
The main direction of use of expanded polystyrene is the insulation of unused attics and flat roofs. Here it is almost ideal, as it is easy to install, inexpensive and perfectly protects roof surfaces from freezing.
To insulate existing roofs from the outside, the current SNiP recommends buying extruded polystyrene foam or penoplex to insulate the attic yourself. This foam has much higher strength. You can walk on it without fear, and even place heavy objects on the foam base.
In combination with all the initial positive characteristics of conventional polystyrene foam, as well as additional advantages in the form of low flammability, penoplex has firmly taken its place as roofing insulation. back to menu
2Insulation technology
There are a great variety of insulation technologies. If you look at SNiP alone for roof insulation, you can find at least three such technologies. But SNiP is only a basic document.
Waterproofing rafters and slopes
We will now look at the two most popular solutions.
One will concern the insulation of the pitched roof. And the second focuses on the arrangement of thermal insulation of a flat, unused roof. to menu
2.1 Insulation of pitched roofs
How to properly insulate the roof of a pitched house? Yes, very simple. This is done in an elementary way.
But first, we note that it is recommended to thermally insulate a pitched roof only with the help of mineral wool. In our method, it is this that is taken into account.
Moreover, special cotton wool is used. It has a slightly lighter overall structure. This affects both the weight of the slabs and their elasticity.
Stages of work:
- We think over an insulation scheme, measure the frame of the rafters. We install waterproofing on the internal cavity of the slopes. We lay the slabs between the rafters as when insulating the roof of a building with mineral wool. If necessary, we install a second level of insulation. We also install a vapor barrier film or membrane against wind loads. We fill the cavity between the rafters with light sheathing .We install the finishing coating.
The installation of insulation is carried out according to a very simple and even pleasant procedure.
All that is required of you is to correctly position the mineral wool between the rafters. As a rule, the width of the slab is slightly greater than the width of the opening. But its elasticity allows you to install the slab without any problems.
The second level of insulation is installed based on special calculations. It is not always necessary, but it is also rarely superfluous.
It is desirable that the insulation for slopes have a thickness of 10 centimeters, so if your thermal insulation layer does not reach this figure, then it is better to install another level.
At the second level, the slabs are laid overlapping, trying to cover the previous joints, thus isolating the cold bridges.
Installation of the finishing coating of a flat roof on foam boards
To increase the reliability of the fastenings, the wool can be additionally secured with dowels with a wide head. But this is already done at will. to the menu
2.2 Insulation of a flat roof
Insulation of a flat roof structure is carried out using a different technology, which, however, is quite natural. Here our task is the correct installation of insulation, and then its waterproofing. Moreover, the lion's share of all work is spent on waterproofing.
Do not pay attention to the fact that polystyrene foam is used in the work, which is not at all afraid of moisture. This makes no difference when it comes to discussing the need to install reliable waterproofing.
For a flat roof, waterproofing is perhaps its most important part. According to the simplest algorithm, it is made from several levels of roofing felt, which is coated with bitumen mastic.
Roofing felt and mastic go well with polystyrene foam boards, and their density allows you to walk on roofing felt without fear of falling through or damaging the thermal insulation layer.
Stages of work:
- We prepare the base, prime it if necessary, clean it from dirt. We install the first level of polystyrene foam on the solution. We coat the joints between the plates. We install the second level of insulation. The installation is also carried out overlapping and using the same technology. We install the waterproofing film. We apply bitumen mastic and glue the base layer of roofing felt. We install the roofing felt waterproofing.
But whether to do it or not is up to you. For existing roofs, such measures will be clearly useful. to menu
2.3 Insulation of a sloped roof (video)
A private house has its advantages over an apartment, but at the same time, furnishing it is a serious responsibility. This housing is created for at least decades of permanent living, and it should be comfortable and convenient.
Considering the Russian climate, the ability of a living space to retain heat is of particular importance. Our ancestors used various organic materials to insulate their homes; Now, along with the development of construction technologies, new materials have appeared that can provide a dry and warm indoor climate. In this article, the reader will learn about one of the most important points - how to insulate the roof of a private house with your own hands.
What to look for when choosing insulation
Since warm air tends to rise, proper roof insulation is not only logical, but also necessary to maintain an acceptable temperature in the house. On the one hand, the roofing material used for insulation must not let out warm air, on the other hand, it must not let in cold air masses from the outside.
The gable roof is the most common in Russia; it has been equipped since ancient times, when log wooden houses were built. Firstly, it retains heat well, and secondly, moisture and snow roll off it without getting inside the home.
Scientific and technological progress has affected construction; new types of insulation with excellent technical parameters are appearing. What should you pay attention to when choosing?
The environmental friendliness indicator comes first, since the material, one way or another, constantly affects people. It is important that the insulation under no circumstances emit substances harmful to health. For example, in summer, under the influence of the sun, it can heat up: even in this case, the insulation must be completely environmentally friendly.
Now the state regulates these indicators, therefore, when purchasing, you need to check that the building material has quality and safety certificates. Thermal conductivity - by its indicator, a person can judge how effectively the material retains heat. It is determined by the coefficient λ - the lower it is, the more effective the insulation. This means that less material will need to be laid for insulation.
Accordingly, this also affects the load on the building. Water absorption. When insulating the roof, the material will constantly come into contact with moisture; this is completely natural. The insulation should absorb as little liquid as possible: the more moisture it contains, the more heat will dissipate.
In addition, the presence of water can cause rotting and decomposition processes (important for organic insulation materials), which significantly reduces the service life of the building material. This indicator is determined by a coefficient: a small value means high quality. Sound insulation is a parameter necessary for comfortable living in a house. The better this indicator is for the selected insulation, the less noticeable the noise from rain and precipitation will be. Flammability.
To insulate a private house, it is recommended to use building materials of class G1. This means that they do not burn without exposure to open fire. Density and specific gravity make it clear what load the insulation will have on the structure of the house. Resistance to temperature changes. This means that the material will retain its properties and shape in both cold and heat.
Also important when choosing: vapor permeability properties (the ability to “breathe”), service life (durability) and ease of installation.
The most common insulation materials
When choosing how to insulate the roof of your house, it must be said that there are the following groups of materials:
- bulk; roll; slab; sprayed.
Below we will take a closer look at the features of the most popular insulation materials, which can be installed with your own hands or using special devices.
Wood sawdust
This is one of the most popular traditional insulation materials that has been used since ancient times. In some places they are still used today, however, modern building materials are increasingly occupying this market niche.
Sawdust is a natural insulation material that has many advantages: it breathes, is environmentally friendly and neutral (it is hypoallergenic).
There are also disadvantages: this insulation rots over time, rodents - mice and rats - settle and breed in it, which is important for a private home. And most importantly, it is a fire-hazardous combustible material, which is important to consider when choosing insulation for the roof.
Speaking of thermal insulation properties, the material can effectively insulate a house if it is applied evenly over half the attic. This wood material creates a favorable climate in the house, reducing the temperature in summer and retaining heat in winter.
Attention! This option is suitable only if the attic space is not used in any way. Otherwise, it is better to use other insulation materials.
Since this is a bulk material, it can be used to insulate flat roofs with a slight slope. It insulates well if it is compacted during installation and covered with a reinforcing mesh, which will maintain the uniformity of the coating. This work can be easily done with your own hands.
The main disadvantage of insulation is its high specific gravity: a layer of expanded clay significantly increases the load on the foundation and load-bearing walls of the house. To achieve good thermal insulation, installation must be carried out correctly.
Ecowool
In another way it can be called cellulose - this insulation is created from waste paper. This is an excellent material for roof insulation because it:
- environmentally friendly; insulates sound well; has excellent thermal insulation.
Manufacturers treat ecowool with special compounds for disinfection, eliminating the appearance of rodents, and with fire retardants to reduce flammability (as the main disadvantage of cellulose). Also, the advantage of the material is its availability - it is inexpensive.
There is only one minus and it is related to the installation features. If you do it yourself, you will need to prepare and purchase special equipment. The insulation is blown into the roof rafter system; to do this, you will have to create closed spaces, which the material will fill.
Mineral wool
This is one of the most common ways to insulate the roofs of houses. Can be produced in the form of slabs and rolls. It is created from mountain minerals and has a fibrous structure and has many advantages:
- excellent thermal insulation; environmentally friendly; resistant to biological influences, does not rot; fibrous structure makes it possible to “breathe”, allow steam to pass through; the material does not burn; easy to install and calculate due to the presence of stable dimensions.
For example, stone wool is used to ensure fire safety of the roof, in addition to insulation.
It should be noted that moisture can worsen the thermal insulation characteristics of the material, therefore during installation it is necessary to ensure the presence of ventilation and waterproofing of mineral wool.
Glass wool
This is also a long-known insulation material; its properties are similar to mineral wool. Made from molten glass.
Important! Due to glass microparticles, filters and respiratory protection must be used during installation.
This insulation is made by foaming glass with carbon, due to which the material acquires:
- environmental friendliness; non-flammability; resistance to bio-impact; low water absorption; long service life.
They are used to insulate any roof; during installation, glue is used to better secure the glass to the roof.
Expanded polystyrene
Or, more simply, polystyrene foam. A very popular material for roof insulation. This insulation provides good thermal insulation, is waterproof, and does not absorb steam.
Important! It is only suitable for pitched roofs due to its flammability and inability to “breathe” or allow steam to pass through.
Expanded polystyrene boards are installed in one layer between the rafters on the roof in a tight manner, without creating gaps. To eliminate them, all connections and joints are filled with polyurethane foam. The top can also be reinforced with tape.
Polyurethane foam
It is also a good insulator. Its advantages:
- light weight; very low thermal conductivity; resistance to bio-impact; excellent waterproofing; good sound insulation.
The material is installed using slabs or spraying. In the latter case, special equipment, including protective equipment, will be required. The advantage of this method is that polyurethane foam will fill all the cracks.
Speaking of slabs, they are quite rigid, but easy to process, and are great for DIY installation.
Penoizol
This material is similar in its qualities to ordinary polystyrene foam, and as an insulation material it can compete with mineral wool and expanded polystyrene. And thanks to the price-quality ratio, in some cases it is even better.
Insulation also occurs using spraying. Special equipment is used for this. The insulation fills all the cracks well, and after drying it does not have much weight.
The material is completely environmentally friendly and safe for human health. The downside is that it absorbs moisture, so the roof must be well vapor-insulated.
Foam concrete
This insulation is durable and reliable; it consists of concrete, cement and sand. Applied using special equipment in a layer of up to 150 mm; The machine unit foams the solution and reduces its density. Thanks to this, the insulation does not place a large load on the building and foundation.
The building material provides excellent thermal insulation; it is non-toxic and fireproof. The foaming nature of foam concrete gives it the ability to “breathe” even after hardening.
Conclusion
In modern times, quite a lot of new building materials have appeared that provide good thermal insulation. Some synthetic substances are close to natural properties, which makes the microclimate in the house better and more favorable. It is possible to install these insulation materials with your own hands and do it for years.