Montesson · report
Renovation in Montesson
In 2025, 98% of the homes authorised were in existing buildings: conversions, extensions and changes of use.
- Homes in existing buildings, 2025
- 98%
Homes authorised in Montesson: new buildings and existing ones
Dwellings authorised each year, by the year the permit was granted: in new buildings, and by works on existing buildings (conversions, extensions, changes of use). SDES Sitadel.
- Existing buildings
- New buildings
Show the numbers
| Year | New buildings | Existing buildings | Total |
|---|---|---|---|
| 2025 | 1 | 45 | 46 |
| 2024 | 78 | 4 | 82 |
| 2023 | 13 | 1 | 14 |
| 2022 | 64 | 2 | 66 |
| 2021 | 122 | 2 | 124 |
| 2020 | 14 | 4 | 18 |
| 2019 | 219 | 7 | 226 |
| 2018 | 94 | 11 | 105 |
| 2017 | 74 | 2 | 76 |
| 2016 | 9 | — | 9 |
| 2015 | 26 | 24 | 50 |
| 2014 | 7 | — | 7 |
| 2013 | 41 | 19 | 60 |
Only permits that create dwellings are listed, so renovation that adds no home (refurbishing, insulating, re-roofing) is not counted. A permit is permission to build, not a finished home. The current year is left out until it is complete.
Other reports for Montesson
At the median sale price, a 90 m² home costs €439,740. With 10% down and a 30-year mortgage, the payment is €1,712 a month. The HCSF caps it at 35% of a household's income.
- Payment, two incomes
- 28%
- Payment, one income
- 56%
Owning a 90 m² apartment costs less each month than renting it. Owning counts interest, running costs and the return the deposit could earn, at apartments' median sale price; rent is the asking rent. Repaying the loan is saving, so it is left out.
- Rent per month
- €1,855
- Owning per month
- €1,371
Figures for Yvelines: Montesson has no reliable figures of its own.
12.7% fewer homes were licensed for construction in the last 12 months than in an average year of the past decade.
- Licensed, 12 months
- 7,492
In 2022 the population fell by 57 while 123 homes were started.
- Homes started, 2022
- 123
- Population change, 2022
- −57
6.2% of the 6,465 homes counted in the 2023 census stood empty, whether for sale, to let or for other reasons.
- Empty, 2023 census
- 6.2%
- Empty homes
- 399