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Rear Extension Approval Rates in Lewisham

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 4,811 real decisions tell us about rear extension outcomes in Lewisham.

4,811 real decisions·January 2020 to September 2026·Updated September 2026
75.7%
Approval Rate
4,811
Decisions
3,640
Approved
1,171
Refused
75.7% approved. But 1,171 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 Lewisham.

TypeDecisionsRate
New Build304
88.8%
Wraparound Extension464
85.1%
Extension (General)2,758
84.1%
Flat Conversion2,781
83.7%
Conservatory372
83.6%
Outbuilding856
83.1%
Garage / Parking3,686
83.0%
Basement1,251
82.5%
Hip-to-Gable Conversion913
82.4%
Dormer2,117
81.6%
Loft Conversion2,701
79.3%
Change of Use (Residential)2,070
78.2%
Side Extension1,199
75.9%
Rear Extension4,811
75.7%
Annex83
69.9%
Front Extension65
61.5%
HMO480
61.3%
See how this applies to your postcode →

What the data tells us

1
75.7% of rear extension applications in Lewisham get approved. That means 1,171 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

1,171 rear extension applications in Lewisham 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 3,840,000+ real decisions

More Lewisham planning data

Nearby councils rear extension data

Methodology: Based on 4,811 planning decisions classified as rear extensions in Lewisham, January 2020 to September 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 Lewisham Council's public planning portal. Full methodology →
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