Roof insulation with foam foam, its features, pros and cons, preparation of the roof for insulation and work technology. Despite the significant advantages, there are still some disadvantages of thermal insulation with penofol. They are related to the characteristics of the material.
One of them is the lack of rigidity of its base, although in certain cases this can be an advantage. The fact is that the insulating effect of polyethylene foam is based on its cellular structure, which contains air, which in itself is an excellent heat insulator. If you press down hard on the coating from above, then air can escape from it, and the quality of the coating will sharply decrease. Because of this, it is not recommended to do the finishing immediately on top of the foam foam. A way out of this situation can be to create a wooden frame from slats. Thanks to him, you can not only fix the finishing material, but also provide a ventilation gap for airing the space above the insulation.
When installing foil-clad foam on the roof, you should not use metal fasteners. Metal conducts heat well, so if the insulation is damaged with self-tapping screws, you can get a lot of "cold bridges". This problem can, of course, be solved by treating each point of the fastener with a sealing compound, but it will be better to simply use glue to fix the foam.
Despite its effectiveness, foil insulation is quite thin. Its thickness is not enough to protect the roof from severe frosts. Therefore, in such cases, penofol is supplemented with other heat-insulating materials. For example, foam plastic or mineral wool can be placed in the cells of the frame designed for fixing the finish. Since penofol, in addition to insulation, serves as a vapor barrier material, its use does not allow the roof to "breathe". At the same time, wooden structures begin to rot, and the air in the attic space becomes dry. The first problem can be solved by the ventilation gap between the surface of the roof slope and the foil insulation, and the second by the use of air humidifiers.
Preparatory work
Before insulating the roof, it is necessary to go through the preparatory stage of work, which is always carried out according to the standard scheme:
- Inspection of the elements of the roof truss structure for damage in the form of cracks or rot. If any are found, beams, bars and boards should be replaced.
- Cleaning the inner surface of the roof slopes from dirt. These can be rust and grease stains, dust, traces of mold, and the like.
- Coating of wooden roof elements with antiseptics, fire retardants and a primer.
- Sealing of junctions - chimneys, ventilation ducts and attic windows.
All protruding parts of structural fasteners must be hidden in the wood in order to avoid damage to the thermal insulation from any nail or screw. At the same time, it is necessary to provide for the laying of communications if the attic space is planned to be used as a heated attic.
Roof insulation technology with penofol
Correct roof insulation must be arranged so that moisture from rain and snow cannot penetrate from above to the roof insulation. The same applies to the intake of humid air from below from the premises of the house. In the event that vapors enter the attic space, the roof structure should provide for natural ventilation, with the help of which they should be removed outside and at least two protective layers of vapor and waterproofing.
The vapor barrier layer must necessarily be part of the roof covering. Its absence can lead to wetting of a massive insulation and heat loss in the house. In order to avoid such a problem in the constructed building, the roof frame will not have to be redone. First, you need to carefully lay a layer of massive insulation, for example, polyurethane foam, and then the foil insulation Penofol.
Air pockets must adjoin the reflective surfaces of penofol. This is half the success of all isolation. In this case, the reflective surfaces of the insulation make the air an additional insulating layer.
Consider step by step the thermal insulation of the roof with a combined insulation. We will choose mineral wool as the main material, and penofol for its protective layers. The procedure looks like this:
- On the inside of the rafters, you need to fix the lathing bars for laying insulation on them. They should be installed with a step of 0, 2-0, 3 m.
- Outside, on the finished crate, it is necessary to tightly lay the mineral wool slabs. If through gaps appear, they must be filled with polyurethane foam.
- After installing all the plates of the main insulation, you can proceed with the waterproofing device. We use penofol as a material for it. It should be nailed to the outside of the rafters. It is necessary to leave an air gap of 5 cm between the mineral wool and the foil insulation - it is required for ventilation.
- Above the foam foam, it is necessary to create a gap for roof ventilation. This can be done with 25x50 mm bars, which should be nailed along the rafters.
- On top of the bars and at the same time across the rafters, planks need to be filled to create a lathing for laying roofing material. The wooden crate should be treated with an antiseptic.
- When the lathing is ready, you can proceed with the device of the vapor barrier layer. Penofol will serve them again. Its sheets must be fixed from the inside with nails on the rafters. In this case, the foil layer should be facing from above towards the premises.
- The insulation is completed by a crate made of strips that need to be stuffed over the vapor barrier layer. It is possible to fix the interior finishing of the roof on it: gypsum board, plywood, lining, etc.
How to insulate the roof with penofol - watch the video:
The work of insulating the roof with foam foil is complicated only by the need for ventilation gaps on both sides of the sheet. If you take it seriously, without violating the technology, the result of conscientious work will not be long in coming. Good luck!
