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Rear Extension Approval Rates in Barnet

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 18,068 real decisions tell us about rear extension outcomes in Barnet.

18,068 real decisions·January 2020 to September 2026·Updated September 2026
75.6%
Approval Rate
18,068
Decisions
13,668
Approved
4,400
Refused
75.6% approved. But 4,400 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.
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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 Barnet.

TypeDecisionsRate
Basement2,664
83.0%
Garage / Parking11,021
82.3%
Extension (General)1,299
82.2%
Hip-to-Gable Conversion3,600
81.8%
New Build1,986
81.7%
Side Extension6,858
81.5%
Conservatory1,568
81.2%
Dormer9,608
81.0%
Loft Conversion8,503
80.7%
Wraparound Extension3,030
80.1%
Front Extension1,871
78.7%
Outbuilding3,301
77.9%
Flat Conversion4,270
76.1%
Rear Extension18,068
75.6%
Annex211
72.0%
Change of Use (Residential)2,064
68.8%
HMO641
43.8%
See how this applies to your postcode →

What the data tells us

1
75.6% of rear extension applications in Barnet get approved. That means 4,400 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

4,400 rear extension applications in Barnet 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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More Barnet planning data

Nearby councils rear extension data

Methodology: Based on 18,068 planning decisions classified as rear extensions in Barnet, 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 Barnet Council's public planning portal. Full methodology →
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