We heat the roof with foam plastic step by step technique

In addition to the insulation of the roof itself, the foam is used to insulate the floors, that is, the floor of the attic. In this case, it is laid on the rough floor, on the previously laid layer of the vapor barrier film, and the top is covered with a layer of plywood, waterproofing and decorative coating.

When buying a foam, you need to choose plates of this size so that the number of joints is minimal. The thickness of the foam for insulation should be at least 10 cm, the density can be taken any, while it should be noted that with increasing density, its mechanical strength and heat-insulating properties increase. Sound insulation properties of foam almost does not have, so for a residential attic must also provide a soundproof layer of at least 5 cm, laying it under the decorative skin. This is especially true for roofs covered with a profiled sheet or metal roof - in the rain, the sound of drops can be heard quite distinctly.

In addition to polystyrene, polystyrene plates can also be used. They have the same advantages as polystyrene, while they have great strength, do not support combustion, they are resistant to damage by rodents. The price of polystyrene is somewhat higher, but because of the best thermal insulation properties, it is possible to take plates of lower thickness.

Technology of roof insulation with foam

1. Thermal insulation of the roof with foam can be done both with the roofing laid and with the roof open. In both cases, the implementation of thermal insulation from the laying of the waterproofing film begins. It is better to choose a special film, for example, Izospan for a roof. It has a membrane structure and produces water vapor in one direction - from inside the heat-insulating "pie" to the outside. The film is put on the rafters, not pulling it. Slack of the film is allowed. Roll unwind across the rafters for the entire length of the roof, while you must ensure that the film was facing a smooth water-vapor-proof layer to the outside. The following strips of film overlap at least 10 cm, and the joints are glued with a special tape. There must always be an air gap between the film and the crate, so a 50 mm block is beaten on the rafters over the film, and the boards of the crate are laid over it, onto which the roofing is laid.
   

   Laying the waterproofing layer

2. Plates of styrofoam are usually placed in the space between the rafters, trying not to leave any crevices. In the size of the slab cut with a clerical or other thin sharp knife on a metal ruler. Fixing the foam to the rafters can be done using auxiliary rails or glue for polystyrene. If the rafters are made of a bar or board, the foam can be glued to the rafters with glue. If the rafters have a circular cross-section, glue fixing may not be sufficient. In this case, a file is made from the board, which holds the plates in two or three places, and the voids between the plates and other elements of the construction are frosted.
   

   Stacking foam plates between rafters

3. It is very important to carefully fill all the cracks to prevent the formation of cold bridges. Temperature changes inside the heat-insulating "pie" lead to the formation of condensate in places subject to cooling, as a result of which leakage may develop or the rotting system may begin to rot. In order to exclude the cold bridges, the foam can be laid in two layers in unison, overlapping the second layer with the joints of the first one. Between each other, the layers are bonded to the glue.
   

   The final stage of the installation of foam between the rafters

4. If you need sound insulation of the attic space, soundproof mats made of fibrous materials are placed on top of the foam plastic. Fibrous materials, when wet, lose their properties, so they must be closed with a vapor barrier.
5. Insulation must be insulated from the interior of the attic by a vapor barrier anticondensate film. It is lapped, carefully glued joints and fastened with a furniture or a construction stapler to the rafters or filing.
   

   Waterproofing of foam insulation with anti-condensation film

6. For fixing the skin, you need guides - wooden bars or profile. Their thickness should provide a ventilation gap of 3-5 mm between the vapor barrier and the skin. As the skin it is better to use natural materials that are not prone to condensation. In addition, when the roof is insulated with polystyrene, it is necessary to equip exhaust ventilation and an adjustable heating system in order to avoid overmoistening of the attic walls in wet weather.

With thermal insulation of floors, the technology is similar to roof insulation. In doing so, it should be remembered that the bottom layer separating the layer of insulation and the rough floor, there must be a vapor barrier film with anticondensate properties, and the upper one, on which the finishing floor is laid, is a waterproofing film. It will protect the heater from waterlogging in case of water leaks. Plates of polystyrene are laid in the spaces between the ceiling beams, fusing slits. To the beams the foam can not be fastened, it will be pressed with a finishing floor.

Polyfoam does not have high resistance to point loads, so when using as a coating of linoleum, cork or thin laminate, it is necessary to cover the foam with moisture resistant plywood or plasterboard. Over the foam, you can also make a concrete screed, in which to lay water warm floors - this will ensure an even warming up of the attic space and adjust the humidity, which will allow maintaining the optimal microclimate there.