What you need to know before insulating your attic
Before embarking on the work, a number of points must be well in mind.
An essential basis: thermal insulation
Whether or not the attic can be converted, their insulation remains economically beneficial for the home, but also ecologically in terms of sustainable development. For new buildings, it is even a legislative necessity; the RT2012 law thus imposes strict requirements, with primary energy consumption limited to 50 kWh / m² per year. For old buildings, dating from times when sustainable development was not particularly a leitmotif, the insulation of the attic is often deficient, with nearly a third of total energy losses.
In order to promote sometimes heavy ecological renovation work, the State has launched a series of aid in recent years, such as Energy Savings Certificates, the Energy Transition Tax Credit, or the VAT at 5, 5%. The famous Eco Loan at zero rate is intended for all housing built before 1990, is granted without conditions of resources, for a maximum sum of 30,000 euros.
To insulate your attic economically and ecologically, the best solution is through "eco-materials". These are materials of natural origin, characterized by a very low carbon footprint, and effectively combating greenhouse gases. Wood and aluminum are key elements of these eco-materials; for the specific field of thermal insulation, there is a whole range that is sometimes surprising. Competing with the famous glass wool, rock wool and sheep's wool offer interesting alternatives or even superior performance, constituting excellent thermal and acoustic insulators.
Cellulose wadding, made from recycled newspapers and papers, is often considered to be the best performing insulation. Straw, flax and hemp, used since the dawn of time by man but thrown into oblivion by concrete, have come back in force since the 2000s. Cork has all the advantages of insulation, in besides being hydrophobic, very fire resistant, and insensitive to pests. Finally, more anecdotally, duck feathers are not only effective for bedding; they are an excellent hygrometric regulator, absorbing excess humidity and rejecting it in dry weather.
Some rules before fitting out your attic
Once the insulation is completed, it is then possible to consider installing the attic. It all depends on the configuration of the latter, and also on the available budget. A surface can be considered as habitable from 1m80, including the installation of thermal insulation and the possible reinforcement of the floor. The slope of the roof must also be at least 35 °.
In addition, an area of less than 20m² requires a prior declaration at the town hall, and beyond a building permit. Once these conditions are met, what happens next is a matter of imagination - and money. A surface area of less than 20m² can typically accommodate a bedroom; between 20 and 30 m², it is possible to create two bedrooms and a bathroom. Beyond 30m², three bedrooms, a bathroom, a dressing room or a large living room can ideally enhance the value of the home.
In the case of roofs of less than 1.80m and / or with slopes of less than 35 °, it is always possible to modify the configuration of the attic, but obviously at a much higher cost. Changing the slope of the roof, or even adding a floor to the home involves completely modifying the architecture - and also calling on an architect.
In the case of very small attics, another solution is to raise the floor or even remove it completely, which makes it possible to considerably increase in height the room previously located below the attic. Once the work is completed, it is compulsory to take out insurance despite the additional costs (3 to 6% of the budget). Ultimate necessity, the new space must be declared to the Public Treasury to recalculate local taxes.