Data-backed planning intelligence · 3,780,000+ decisions analysed across England

Rear Extension Approval Rates in Windsor & Maidenhead

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 2,239 real decisions tell us about rear extension outcomes in Windsor & Maidenhead.

2,239 real decisions·January 2020 to August 2026·Updated August 2026
84.5%
Approval Rate
2,239
Decisions
1,892
Approved
347
Refused
84.5% approved. But 347 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.

These are council averages. Your property is specific.

Two houses on the same street can get different outcomes.
Check your postcode to see what actually happens near your address.

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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 Windsor & Maidenhead.

TypeDecisionsRate
Loft Conversion290
88.6%
Basement103
88.3%
Conservatory199
86.9%
Hip-to-Gable Conversion143
86.0%
Front Extension633
85.0%
Rear Extension2,239
84.5%
Side Extension1,435
83.6%
Extension (General)213
83.6%
Garage / Parking1,635
82.4%
Dormer743
80.1%
Outbuilding597
78.7%
New Build155
78.1%
Change of Use (Residential)313
78.0%
Wraparound Extension122
76.2%
Annex45
62.2%
See how this applies to your postcode →

What the data tells us

1
84.5% of rear extension applications in Windsor & Maidenhead get approved. That means 347 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

347 rear extension applications in Windsor & Maidenhead have been refused since 2020. Many of those homeowners had already paid for drawings and application fees. A free, property-specific report shows you what gets approved — and what gets refused — near your property.

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Free · Property report emailed in minutes · Based on 3,780,000+ real decisions

More Windsor & Maidenhead planning data

Nearby councils rear extension data

Methodology: Based on 2,239 planning decisions classified as rear extensions in Windsor & Maidenhead, January 2020 to August 2026. 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 Windsor & Maidenhead Council's public planning portal. Full methodology →
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