🏡 Is building a sunroom always allowed in France?
Yes, but under certain conditions. A sunroom is considered a home extension, which means it alters the exterior appearance of the property and increases its living space. Depending on its size and the location of your home, urban planning permission may be required:
👉 Prior Notice of Works
Required if:
- The added surface area is between 5 m² and 20 m²;
- Up to 40 m² if your property is located in an urban zone governed by a Local Urban Plan (PLU);
- And the total surface of the home remains under 150 m² after construction.
👉 Building Permit
Required if:
- The sunroom exceeds 20 m² (or 40 m² in an urban zone) and your home reaches or exceeds 150 m² in total;
- You are located in an area not covered by a PLU;
- Or your property is situated in a protected or listed zone.
🔔 Important: If the extension brings the total floor area to more than 150 m², the use of a licensed architect (DPLG or HMONP) becomes mandatory.
🏛️ What are the administrative steps for building a sunroom?
To ensure compliance with regulations, follow these key steps:
- Consult your local planning office to check zoning rules, building restrictions, and protected area regulations (PLU, easements, heritage zones…).
- Submit your application either at the town hall or via the online urban planning portal.
- Prepare the documentation: For a prior notice of works: Cerfa form, architectural plans, photos, and a descriptive statement; for a building permit: full application file, including a thermal performance study if required.
- Wait for approval: Around 1 month for a prior notice; 2 to 3 months for a building permit, depending on the project’s complexity.
👉 Special Cases: Condominiums, Protected Zones & Heritage Authorities (ABF)
If your home is part of a condominium, you must obtain approval from the general assembly before making any modifications.
If your property is located in a heritage site, near a historical monument, or in a natural conservation area, you’ll need approval from the Architectes des Bâtiments de France (ABF). This often includes mandatory aesthetic adjustments to preserve the area’s architectural integrity.
In Summary: What to Know Before Building a Sunroom
✅ Check local regulations with your town hall
✅ Determine whether a prior notice or building permit is required
✅ Be mindful of rules related to protected zones or condominiums
✅ Work with experienced professionals to avoid setbacks
Planning a sunroom that requires prior approval?
17:17 Interiors can support you in designing your project and preparing all required documents.
📩 Contact 17:17 Interiors for a tailored consultation.
Our bespoke approach and keen eye for detail make all the difference
