Side extensions in Horsham
2,043 applications since 2020. 1,810 approved and 90 refused. Refused: about 1 in 21 here, about 1 in 7 across the councils we cover.
Last updated 9 November 2026.
Without planning permission
- Single storey, no higher than 4 m
- No wider than half the width of the original house
- Not facing a road
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 | 180 | 132 | 7 |
| 2025 | 247 | 229 | 6 |
| 2024 | 226 | 200 | 14 |
| 2023 | 285 | 248 | 12 |
| 2022 | 359 | 314 | 25 |
| 2021 | 445 | 409 | 16 |
| 2020 | 301 | 278 | 10 |
Architects and agents, last 5 years
| Firm | Approved | Decided |
|---|---|---|
| Dma Building Designs | 65 | 67 |
| LDV Architecture Ltd | 43 | 44 |
| dk planning & design | 43 | 43 |
| Mark Alford Design Limited | 41 | 41 |
| Folkes Architects | 17 | 17 |
| abm building services ltd | 17 | 17 |
| Downsview Associates | 16 | 16 |
| Eye For Detail Architects | 16 | 16 |
| NJA Town Planning Ltd | 15 | 16 |
| PS Designs Ltd | 15 | 16 |
Neighbouring councils
| Council | Approved | Refused | How often |
|---|---|---|---|
| Crawley | 445 | 87 | about 1 in 6 |
| Mid Sussex | 1,735 | 110 | about 1 in 17 |
| Mole Valley | 10,979 | 1,519 | about 1 in 8 |