Loft conversions and dormers in Hertsmere
2,684 applications since 2018. 2,094 approved and 329 refused. Refused: about 1 in 7 here, about 1 in 6 across the councils we cover.
Last updated 9 November 2026.
Without planning permission
- Up to 40 cubic metres of extra roof space on a terrace, 50 on a semi or detached house
- Not on the roof slope facing a road, and no higher than the existing roof
- Materials similar in appearance, set back about 0.2 m from the eaves, and side windows obscure-glazed
England, houses only. Flats, listed buildings, conservation areas and Article 4 directions change this. The full rules.
Year by year
| Year | Applications | Approved | Refused |
|---|---|---|---|
| 2026 | 201 | 132 | 16 |
| 2025 | 267 | 227 | 17 |
| 2024 | 241 | 197 | 24 |
| 2023 | 279 | 214 | 46 |
| 2022 | 346 | 264 | 54 |
| 2021 | 377 | 310 | 43 |
| 2020 | 324 | 262 | 31 |
| 2019 | 300 | 233 | 38 |
| 2018 | 349 | 255 | 60 |
Architects and agents, last 5 years
| Firm | Approved | Decided |
|---|---|---|
| Steene Associates (Architects) Ltd | 22 | 23 |
| Town & Country Planning Limited | 17 | 18 |
| A.J Ferryman & Associates | 17 | 17 |
| PLK Design Limited | 14 | 17 |
| Area Design | 14 | 15 |
| p. w. roseman associates limited | 9 | 10 |
| Warner Planning | 9 | 9 |
| Dusek Design Associates Ltd | 8 | 8 |
| Phi Architectural Services Ltd. | 8 | 8 |
| Architects Corporation Ltd | 7 | 8 |
Neighbouring councils
| Council | Approved | Refused | How often |
|---|---|---|---|
| Barnet | 8,390 | 1,972 | about 1 in 5 |
| Enfield | 4,764 | 1,323 | about 1 in 5 |
| Harrow | 2,407 | 709 | about 1 in 4 |
| Welwyn Hatfield | 761 | 263 | about 1 in 4 |