Data-backed planning intelligence · 2,500,000+ decisions analysed across England

Rear Extension Approval Rates in Horsham

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 2,125 real decisions tell us about rear extension outcomes in Horsham.

2,125 real decisions·January 2020 to present·Updated March 2026
95.3%
Approval Rate
2,125
Decisions
2,025
Approved
100
Refused
95.3% approved. But 100 refused since 2020. Each refusal cost the homeowner time and money on drawings and application fees. Understanding your local data before you apply is the difference between confidence and a costly gamble.

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Why rear extension approval rates matter

Rear extensions sit in the middle of the pack nationally. They're common enough that councils have clear precedent — but that cuts both ways. If your neighbours have been refused, that precedent works against you too.

Rear Extension approval rate by ward

#WardDecisionsApprovedRate
1Storrington and Washington55
100.0%
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These are council averages. Your property is specific.

Two houses on the same street can get different outcomes.
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How rear extensions compare to other project types

Not all applications are treated equally. Here's how rear extensions stack up against other common projects in Horsham.

TypeDecisionsRate
Conservatory457
98.2%
Basement32
96.9%
Wraparound Extension314
96.8%
Side Extension1,319
96.3%
Front Extension389
96.1%
Rear Extension2,125
95.3%
Loft Conversion233
94.4%
Dormer661
91.4%
Hip-to-Gable Conversion79
91.1%
Extension (General)430
90.2%
Outbuilding580
89.5%
Garage / Parking2,083
88.3%
Annex144
84.7%
New Build771
78.6%
Flat Conversion30
76.7%
Change of Use (Residential)678
72.9%
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What the data tells us

1
95.3% of rear extension applications in Horsham get approved. That means 100 homeowners since 2020 have been refused. Not terrible odds, but not a foregone conclusion.
3
Council averages are starting points, not guarantees. The decisions that matter most are the comparable ones near your specific property — because planning officers look at precedent, character and the immediate context of your street.

Before you spend £5,000+ on architects and drawings

100 rear extension applications in Horsham have been refused since 2020. Many of those homeowners had already paid for drawings and application fees. A £79 report shows you what gets approved — and what gets refused — near your property.

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Free instant check · Pro Report £79 · Based on 2,500,000+ real decisions

More Horsham planning data

Nearby councils rear extension data

Methodology: Based on 2,125 planning decisions classified as rear extensions in Horsham, January 2020 to present. Classification uses keyword matching against proposal descriptions (matching generate_site_data.py rules). A single application may appear in multiple categories. Approval rate = approved / (approved + refused). Pending, withdrawn and invalid applications excluded. Data from Horsham Council's public planning portal. Full methodology →
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