Renovating and fitting out your attic has been a trend that has been increasingly popular with the French in recent years. This solution is indeed ideal for having additional living space without causing major extension work on the house. Games room, guest bedroom, parental suite, office, library, cinema room… all ideas are possible. To support you in the realization of your project, here is our advice and the budget you will need to consider.
What are the obligations to respect for the conversion of the attic?
The renovation and development of attics are subject to certain legal obligations.
- The declaration of work: if the renovation of your attic gives rise to the addition of a living area of 5 to 20 m², if this gives rise to a modification of your facade or your roof, you will be required to carry out a declaration of work to the town hall of your municipality.
- The building permit: if the renovation of your attic involves the addition of a living area greater than 20 m² or if the total area of your home is to exceed 150 m², you will need to obtain a building permit from the town hall of your municipality.
- The intervention of an architect: if the renovation of your attic has the effect of extending the total living area of your home to more than 150 m², you will be required to involve an architect.
- If your home is located near a historic site or monument or if it is located within a protected area, you will be required to obtain the authorization of an architect from the Bâtiments de France and a specific building permit.
- On the other hand, if the ceiling height of the attic you are renovating is less than 1.80 m, the living area of your house is not impacted and no declaration to the town hall is required.
- If you wish to install a new roof window, you must consult the town planning rules of your municipality and respect the land use plan which imposes certain standards on you in terms of height, size and distance with regard to other openings, but also in relation to property boundaries in your neighborhood.
Renovating your attic: the budget to be planned item by item
The average cost to consider for the renovation of attics varies between 500 and 1,500 euros per square meter. It is obviously proportional to the nature and complexity of the work carried out.
- A light layout will cost you between 500 and 900 euros per square meter. It includes insulation, partitions, floor and wall coverings, the addition of a roof window and a simple electrical renovation.
- A more complete layout will cost you between 900 and 1,500 euros per square meter. It includes insulation, partitions, floor and wall coverings, the addition of one or more roof windows, a complete electrical renovation, the addition of plumbing elements and the creation of an expensive room bathroom type.
To help you better estimate the budget you will need to renovate your attic, we present the average prices charged for each item, item by item.
Electricity in the attic
The bill for the electrical installations needed to renovate your attic depends on your needs and the use you will make of the room. However, be aware that a competent electrician charges between 50 and 100 euros for each hour of work. The average budget for electricity varies between 1,200 and 2,500 euros.
Plumbing in the attic
If you want to convert your attic into a bathroom or install a water point for more comfort, you will need to plan the budget necessary for plumbing work. A plumber charges an average of 100 euros for his working hours. The average budget for this type of service is around 1,000 euros.
Air conditioning and heating in the attic
Seek the advice of an expert to equip your attic with a suitable air conditioning and heating system.
The attic must be properly insulated to be both habitable and not to impact the rest of your home. Well-insulated attics will indeed save you a lot of money on heating in winter and will make the summer season much more bearable in terms of indoor heat. Several devices are possible to properly insulate your attic.
- An insulating mattress, made up of several layers of cellulose or mineral fibers allows you to have a good thermal barrier which insulates you from the outside while preserving the interior heat and freshness. Count 5 to 10 euros per square meter, excluding installation.
- Blown cellulose is easy to install and provides good thermal insulation. It is very resistant to humidity and insects and has the advantage of isolating every corner effortlessly. At its cost varying between 2.50 and 5 euros per square meter, add that of labor between 60 and 75 euros per hour.
- The heat shield is a suitable solution for hot regions. It forms an anti-radiation barrier that maintains a good temperature in the attic. Count 1.50 to 3 euros per square meter, excluding installation.
- Injected polyurethane foam, whether open or closed cell, is ideal for properly insulating attic floors, walls and ceilings. More effective in terms of thermal insulation than the other forms, it penetrates all the interstices without difficulty to also reduce noise. Allow 5 to 7 euros per square meter for open cells and 7 to 10 euros per square meter for closed cells, excluding installation.
On average, the installation of interior insulation costs between 20 and 50 euros per square meter, supply included, and between 100 and 120 euros per square meter for exterior insulation.
Proper ventilation of the attic is essential to allow good air circulation and prevent the development of humidity.
- For the installation of a VMC (controlled mechanical ventilation), plan between 800 and 1,500 euros approximately. It consists of evacuating the air to the outside and bringing in new air.
- For the installation of an attic fan, count on average 500 euros. Unlike the VMC, it only serves to bring fresh air into the attic.
Access to the attic
The staircase that leads to the attic is often forgotten in the calculation of the overall budget necessary for the renovation work; however, it is essential to access the room.
For the installation of a staircase, your budget can vary between 500 and 10,000 euros. This colossal price difference is justified by the drilling and development work to be carried out, the model of staircase chosen, the complexity of access to the work and the prices charged by the professional for the installation.
The windows in the attic
To let light into your attic and promote good air circulation, you will need to provide at least one roof window. For this type of opening, allow between 150 and 2,000 euros.
Attic walls and ceilings
Renovating your attic may require installing a clean ceiling and installing or modifying partitions to divide up the space. You will then need to provide the wall and ceiling coverings necessary to fit them out.
- For the installation of a ceiling and partitions, plan a budget oscillating between 10 and 50 euros per square meter.
- The installation of wallpaper will cost you between 15 and 150 euros per square meter.
- The installation of the paint will be invoiced to you approximately 30 euros per square meter.
- Adding finishes (borders, skirting boards, panels, etc.) will cost you around 1,000 euros, installation included.
The layout of your attic also includes flooring. For such a room, think about the issues of thermal and acoustic insulation when making your choice. Indeed, it is important that the quality of your floor is sufficient to reduce the risk of heat loss and to avoid disturbing the living spaces located below the attic and vice versa. Similarly, if your attic is used to house a bathroom, for example, prefer a non-fragile and water-resistant floor such as tiles or laminate; avoid parquet or carpet.
- For laying tiles, count on average 30 to 150 euros per square meter, supply included.
- For laying parquet, allow 40 to 200 euros per square meter, supply included.
- For the installation of thick carpet, count 20 to 70 euros per square meter, supply included.
- For the laying of a laminate covering, allow 40 to 80 euros per square meter, supply included.
Whether you plan to install a roof window or not, it is important to choose sufficient and well-distributed lighting to illuminate the entire space.
- Recessed spotlights are a practical solution that covers the room well without distorting the ceiling and without requiring too much space. Allow around 40 to 160 euros per piece, installation included.
- Classic lighting fixtures are very popular for their great variety of styles. They can indeed represent a decorative piece in their own right. On the other hand, some may seem cumbersome in attics with a reduced surface area. Count 70 to 200 per piece, installation included.
- To install wall lights that provide a more subdued and warm light, your budget will vary between 80 and 200 euros per piece.