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

Rear Extension Approval Rates in Hounslow

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 26,504 real decisions tell us about rear extension outcomes in Hounslow.

26,504 real decisions·January 2020 to present·Updated March 2026
84.9%
Approval Rate
26,504
Decisions
22,511
Approved
3,993
Refused
84.9% approved. But 3,993 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.

Ward gap in Hounslow: Chiswick Riverside approves 100.0% of rear extension applications while Hanworth Village sits at 50.0%. That 50.0% gap means your postcode is one of the strongest indicators of outcome.

Rear Extension approval rate by ward

#WardDecisionsApprovedRate
1Chiswick Riverside55
100.0%
2Hounslow South55
100.0%
3Feltham North65
83.3%
4Osterley & Spring Grove1210
83.3%
5Hanworth Park65
83.3%
6Chiswick Gunnersbury54
80.0%
7Heston Central85
62.5%
8Feltham West53
60.0%
9Hanworth Village63
50.0%
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These are council averages. Your property is specific.

A rear extension has a 100.0% approval rate in Chiswick Riverside but just 50.0% in Hanworth Village.
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 Hounslow.

TypeDecisionsRate
Conservatory1,925
95.0%
Extension (General)3,033
92.9%
Dormer1,373
90.5%
New Build4,779
90.0%
Loft Conversion12,007
89.7%
Basement1,485
89.0%
Wraparound Extension1,494
88.9%
Garage / Parking8,713
88.6%
Side Extension7,753
88.1%
Hip-to-Gable Conversion3,244
85.4%
Rear Extension26,504
84.9%
Front Extension1,034
83.0%
Change of Use (Residential)3,085
82.7%
Outbuilding4,154
80.6%
Flat Conversion1,402
72.9%
Annex110
66.4%
HMO338
49.7%
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What the data tells us

1
84.9% of rear extension applications in Hounslow get approved. That means 3,993 homeowners since 2020 have been refused. Not terrible odds, but not a foregone conclusion.
2
Your ward matters more than you think. The 50.0% gap between Chiswick Riverside (100.0%) and Hanworth Village (50.0%) means your postcode is one of the strongest indicators of outcome.
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

3,993 rear extension applications in Hounslow 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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More Hounslow planning data

Nearby councils rear extension data

Methodology: Based on 26,504 planning decisions classified as rear extensions in Hounslow, 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 Hounslow Council's public planning portal. Full methodology →
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