What thermal and ecological insulation for lost attics? What price ?


The roof is responsible for 30% of heat loss in a house. A phenomenon which has repercussions on the heating bill as well as on the comfort of the inhabitants. When poorly insulated, the attic is largely responsible for this loss. Reinforcing the insulation of the attic must therefore be the priority. Even if it means seeking excellence, it is better to use ecological insulation that has no harmful impact on health and the environment.

Cellulose wadding

Cellulose wadding is the “must” when it comes to ecological insulation. This material, made from recycled paper treated against fire and against rodents, develops excellent thermal performance. Depending on the quality of the product used, the thermal resistance R ranges from 3.9 to 5. Cellulose wadding also displays unparalleled phase shifting power. It takes about 10 hours for the heat to pass through the insulation layer. This helps prevent the heat from coming out during the winter and entering during the summer. Thanks to natural additives, the fire resistance is also improved. On the price side, cellulose wadding is once again doing well by posting competitive prices. It takes between 25 and 30 euros per m² to insulate lost attics if the intervention is carried out by a professional and almost half that price if we only talk about the raw material.

Cotton wool

For equal performance, cotton wool has the advantage of being lighter than cellulose wadding. It can be easily implemented in all ceilings whether plasterboard, suspended or other. Another advantage: it is not necessarily useful to use a machine for its application. Spreading can also be done by hand. A good thing for individuals who would consider doing the job themselves. Loose cotton wool will cost them around 12 euros per m² and 6 to 10 euros per m² for rolls of 12 meters.

Bulk cork

Versatile, fire and humidity resistant, ecological and rarely attacked by parasites, insects or rodents, loose cork also has many advantages. Its greatest asset remains its ease of installation. Just dump the product on the floor and level with a rake. The individual can therefore install himself and does not necessarily need a snowblower. On the other hand, cork is penalized by its relatively high price, ranging from 10 to 30 euros per m².

Cardboard fiber

Cardboard fiber is one of the latest in ecological insulation and it has a promising future ahead of it. This material, quite similar to cellulose wadding, is really beneficial for the environment. It is formed with recycled cardboard which does not contain ink unlike recycled newspaper. Cardboard fiber also emits less dust, remains easy to apply and develops good thermal performance. In bulk, its cost is around 12 euros per 10 kg bag.