How to make your home extension a success with an interior architect

Need more space? Add a bedroom, create an independent studio, extend the living area… A home extension is an ideal way to gain square meters and increase property value. We support extension projects in Paris, Le Perche, on the French Riviera, and across France—with an end-to-end approach focused on use, circulation, daylight, and finishing.

Extensions and enlargements: our approach

Do you design extensions and enlargements?

Yes. We design bespoke extensions to blend the new volume seamlessly with the existing home. The objective isn’t “one more room”, but a house that works better—functionally and aesthetically.

Examples of projects

Paris: rooftop extensions or attic conversions to gain valuable square meters.
Le Perche: timber or glass extensions to modernize character homes.
French Riviera: pool houses, premium annexes, volumes opening onto outdoor living.

Key point: a successful extension means obvious circulation, coherent daylight, and finishes aligned with the existing home.

Before any filing (prior declaration / permit): lock down three points—opening placement (daylight), flows (circulation/access), and junctions (levels, materials, thresholds). These are the most expensive mistakes to fix later.

Registered architect (HMONP/DPLG): a structured partnership

Do you work with registered architects (HMONP/DPLG)?

Absolutely. For certain thresholds (including total floor area over 150 m²), a registered architect is mandatory. We work closely with qualified architect partners across France.

They handle: structure, compliance, and permit applications.
We handle: interior design, flows, daylight strategy, and overall coherence.

Result: a robust project technically—and coherent aesthetically—without compromising how the home is used.

Administrative steps: prior declaration, building permit, planning rules

Do you manage the administrative process?

Yes. We support you end to end. With our architect partners, we prepare the packages and frame local constraints.

Prior declaration: depending on the extension scope and any façade changes.
Building permit: for projects requiring full authorization.
Local planning rules: often stricter in protected areas (Perche) or coastal zones (French Riviera).

Good reflex: framing planning constraints early avoids redesigns after refusals or requests for changes.

Why hire an interior architect for an extension?

What’s the advantage for a home extension?

The biggest advantage is the global approach. While a contractor focuses on structure, we focus on use: how you live, how you move through the home, where daylight should enter, and how the extension integrates into everyday life.

What makes the difference

Flows & circulation: an extension that improves the house—not a “block” appended to it.
Daylight: openings and proportions designed for comfortable volumes.
Finishes: consistent materials, detailing, junctions, joinery, and quality level.

Goal: expand without breaking the home’s balance—and increase value in a way that’s immediately obvious.

Extensions across France

Do you work nationwide?

Yes. With our network of architect partners and local contractors, we manage extension projects across France with rigorous follow-up—townhouses, rural properties, contemporary villas.

Key takeaway: a successful extension rests on three pillars: an intelligent layout, a clear technical/administrative package, and a site managed without drift.

Planning an extension? Share the city, the surface area, and your goal (bedroom, studio, living space).

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Conclusion

A well-designed extension shouldn’t feel like an “add-on”—it should naturally continue the home. By combining interior design, technical coordination (with architect partners when required), and structured site supervision, you secure the budget, timeline, and—most importantly—the quality of the final result.

Home extension: succeed with an interior architect