When extension rhymes with insulation

When the house lacks a bit of volume and everyone would like a space of their own, converting the attic is a possibility that could seduce many. But is it always possible? You should not start work without authorization, at the risk of being "annoyed" afterwards. Whether it is to gain height or width... there is surely a little regulation that lies dormant in the urban planning department.

Which authorization to fit out one's attic?

It is obviously rare to be exempted from any authorization when you transform your attic into rooms.
Indeed, one is almost always confronted with the creation of floor space and/or the modification of the external aspect by making openings to put roof windows for example.
First of all, it is necessary to determine if your attic is really suitable for conversion. The administrative jurisprudence has determined five criteria that must be combined:
- A ceiling height of at least 1.80 m.

- A framework not encumbered by trusses (the development must not lead to modify the framework to remove its encumbrance).

- An existing floor that can support loads related to the dwelling (reinforcement of the floor will not be necessary).

- Accessibility by normal means.

- The existence of openings to the outside.

If your attic can be converted, you will have to go to the next step: obtain the necessary authorization!
Thus, a building permit is necessary:
- Outside urban areas of a PLU (local urban plan) when creating a floor area greater than 20 square meters.
- In the urban zones of a PLU when creating a floor area greater than 40 square meters or when creatingation of a surface area of more than 20 square meters when this would have the effect of bringing the total surface area of the construction beyond one of the thresholds fixed in article R. 431-2 of the Urban Planning Code.
It will only be necessary to make a prior declaration in the following cases:
- Outside the urban zones of a PLU: when creating a floor area of more than 5 square meters.
- In the urban zones of a PLU: for the creation of a floor area between 20 and 40 square meters.

However, be careful if you are in the case of works that do not require an urban planning authorization for the creation of floor space.A prior declaration could still be required if this development leads to a change in the external appearance of the house, for example by installing a larger roof window or transforming dormers into windows.

What solutions for a beautiful design?

There is no shortage of ideas to enhance your interior by transforming your attic into one or more additional rooms! Create a new space to work, a room to welcome your friends or a playroom for the children (and why not for yourself): the possibilities are endless when you have extra space. But be careful, you should not take this project lightly because converting attic space is something you should think about well in advance. Indeed, you have to anticipate a lot of things: insulation, electricity, heating, water supply and drainage if you want to create a bathroom or a toilet for example. Many trades will have to be involved, unless you are the "king" of renovation and you master all these techniques. Calling on professionals is often much more prudent because it is not a question of doing a little DIY! Let yourself be tempted by the design of an office space. Telecommuting has developed strongly since the health crisis, so it is important to have a quiet place to work serenely. To be as quiet as possible, bet on a good acoustic and thermal insulation to avoid shivering in front of your computer all winter. Also choose a suitable lighting so as not to strain the view.
And why not a playroom? A corner for the children and a space for the parents. Install a pool table, a foosball table, cushions and let's go for evenings of sharing for the young and the old. The cinema room in the attic seems to be rather compromised (even if you dreamed of it...) because because of the slope of the roof, your screen might not be very flat. When the family grows, making new rooms under the roof is a possibility that seduces many. This obviously avoids the hassle of moving house.
It will then be necessary to consider opening other windows for each of the rooms, to insulate properly because under the roof you risk being very hot in summer and very cold in winter. The insulation specialists will advise you on the most suitable solution for your house. They will also give you an estimate of the cost of the work so that you don't have to take a chance.

Which aids to budget the work?

For some aids: it's over! This is the case forattic insulation for 1 € and the premium "coup de pouce isolation". However, no need to worry, there are other aids that can be requested.
- MaPrimeRénov '. Certain conditions must be met to obtain this aid to insulate your attic. Its amount depends on resources and the work must be done:
by a professional RGE (Recognized guarantor of the environment);
in a primary residence;
and it must be built for more than two years.
- The eco-loan at zero rate (eco-PTZ)
It is possible to obtain a loan of 10 000 € for your roof and attic insulation work, from a bank that offers this type of loan.
The work must be carried out by an RGE-labeled professional to be eligible for the eco-PTZ.
- Energy saving certificates. These are the energy suppliers who offer this financial aid.
To benefit from it, your work must meet certain criteria. After work carried out by a professional, the attic must have a thermal resistance R greater than or equal to
7 m².K/W in lost attic and greater than or equal to 6 m².K/W in roof slope. The materials used must be certified ACERMI or follow the standards NF EN ISO/CEI 17025 and NF EN 45011 of the COFRAC or be of certification CE.
- VAT at 5.5% ! If you use a company to supply and install your insulation in your attic, you can benefit from a reduced VAT rate of 5.5%. This is still better than the standard rate of 20%. It applies to labor and the purchase of insulation (cork, cellulose wadding, glass wool ...)
- The aid of the ANAH. The national housing agency offers assistance. More info on : www.anah.fr

Stéphanie Swiklinski