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

Rear Extension Approval Rates in Slough

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 7,207 real decisions tell us about rear extension outcomes in Slough.

7,207 real decisions·January 2020 to August 2026·Updated August 2026
83.7%
Approval Rate
7,207
Decisions
6,029
Approved
1,178
Refused
83.7% approved. But 1,178 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 Slough.

TypeDecisionsRate
Loft Conversion1,166
87.5%
Conservatory178
86.0%
Dormer871
85.6%
Wraparound Extension928
85.3%
Garage / Parking1,274
84.1%
Rear Extension7,207
83.7%
Hip-to-Gable Conversion360
83.3%
Outbuilding1,263
82.4%
Side Extension2,822
82.4%
Extension (General)328
81.4%
Flat Conversion24
79.2%
Annex28
78.6%
Change of Use (Residential)777
78.2%
Front Extension667
74.4%
New Build246
71.5%
HMO59
45.8%
See how this applies to your postcode →

What the data tells us

1
83.7% of rear extension applications in Slough get approved. That means 1,178 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

1,178 rear extension applications in Slough 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 Slough planning data

Nearby councils rear extension data

Methodology: Based on 7,207 planning decisions classified as rear extensions in Slough, 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 Slough Council's public planning portal. Full methodology →
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