- Characteristics of the insulation from the outside
- Benefits of outdoor insulation
- Disadvantages of exterior insulation
The insulation of a house roof from the outside is an alternative to the method carried out from inside the dwelling. Complete description of this technique.
Characteristics of the insulation from the outside
The insulation of a roof from the outside is a complex operation because it supposes to remove the roof covering of the house (tiles, slates...).
There are different ways to insulate a roof from the outside, the main ones are:
- Self-supporting panels: affixed directly to the frame, they cover the entire roof in one piece but require in some cases the removal of the rafters. These panels are composed of the roof support, the insulation, and according to the models of an apparent sub-surface which constitutes the clothing of the attics (wainscoting, plaster...).
- The so-called "Sarking" method: initially used for the construction of the chalets, this process develops more and more. It consists in putting the insulating plates transversely between the frame and the roof; it nevertheless implies raising the roof several centimeters.
Also, concerning dwellings equipped with roof-terraces, the insulation is done obligatorily by the outside.
Benefits of outdoor insulation
Exterior insulation of the roof has several advantages over the technique implemented from inside the house. On the one hand, it entails neither loss of living space, nor need to leave the premises pending work, or to redecorate the attic built after work.
On the other hand, it is the most efficient vis-à-vis the thermal bridges (areas of weakness in the insulation, at the junction of the walls for example).
Disadvantages of exterior insulation
Nevertheless, this solution has certain disadvantages. Indeed, the insulation of a roof from the outside being relatively expensive, of the order of 50 to 200 euros of the m2It is technically demanding and requires a feasibility study, especially to ensure that the roof structure is able to support the weight of the materials. In addition, in some cases, certain permissions are required.
That is why this method is primarily considered during the construction of new houses or during renovation work of the roof.