Data-backed planning intelligence · 2,500,000+ 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 2,671 real decisions tell us about rear extension outcomes in Slough.

2,671 real decisions·January 2020 to present·Updated March 2026
84.3%
Approval Rate
2,671
Decisions
2,251
Approved
420
Refused
84.3% approved. But 420 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 Slough: Farnham approves 100.0% of rear extension applications while Upton sits at 60.0%. That 40.0% gap means your postcode is one of the strongest indicators of outcome.

Rear Extension approval rate by ward

#WardDecisionsApprovedRate
1Farnham66
100.0%
2Langley Meads87
87.5%
3Langley Marish76
85.7%
4Langley St. Marys54
80.0%
5Cippenham Green54
80.0%
6Manor Park & Stoke54
80.0%
7Unknown64
66.7%
8Baylis & Salt Hill53
60.0%
9Upton53
60.0%
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These are council averages. Your property is specific.

A rear extension has a 100.0% approval rate in Farnham but just 60.0% in Upton.
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
Conservatory46
91.3%
Wraparound Extension392
87.5%
Loft Conversion590
86.9%
Side Extension1,026
86.4%
Outbuilding590
85.3%
Dormer395
84.3%
Rear Extension2,671
84.3%
Garage / Parking503
82.9%
Front Extension326
82.2%
Hip-to-Gable Conversion214
82.2%
Extension (General)122
75.4%
New Build36
69.4%
Change of Use (Residential)286
66.8%
HMO34
44.1%
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What the data tells us

1
84.3% of rear extension applications in Slough get approved. That means 420 homeowners since 2020 have been refused. Not terrible odds, but not a foregone conclusion.
2
Your ward matters more than you think. The 40.0% gap between Farnham (100.0%) and Upton (60.0%) 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

420 rear extension applications in Slough 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 Slough planning data

Nearby councils rear extension data

Methodology: Based on 2,671 planning decisions classified as rear extensions in Slough, 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 Slough Council's public planning portal. Full methodology →
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