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

Rear Extension Approval Rates in Birmingham

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 13,248 real decisions tell us about rear extension outcomes in Birmingham.

13,248 real decisions·January 2020 to present·Updated March 2026
87.2%
Approval Rate
13,248
Decisions
11,547
Approved
1,701
Refused
87.2% approved. But 1,701 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.

Rear Extension approval rate by ward

#WardDecisionsApprovedRate
1Unknown10791
85.0%
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These are council averages. Your property is specific.

Two houses on the same street can get different outcomes.
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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 Birmingham.

TypeDecisionsRate
Conservatory166
88.0%
Wraparound Extension1,842
87.8%
Rear Extension13,248
87.2%
Side Extension5,640
87.1%
Outbuilding757
86.0%
Front Extension1,556
85.3%
New Build3,721
83.2%
Extension (General)650
80.8%
Garage / Parking1,578
79.7%
Basement127
79.5%
Dormer2,363
76.1%
Loft Conversion791
74.1%
Annex91
69.2%
Hip-to-Gable Conversion330
63.6%
HMO1,002
60.0%
Change of Use (Residential)1,863
55.1%
Flat Conversion297
52.2%
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What the data tells us

1
87.2% of rear extension applications in Birmingham get approved. That means 1,701 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

1,701 rear extension applications in Birmingham 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 Birmingham planning data

Nearby councils rear extension data

Methodology: Based on 13,248 planning decisions classified as rear extensions in Birmingham, 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 Birmingham Council's public planning portal. Full methodology →
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