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Rear Extension Approval Rates in Sefton

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 533 real decisions tell us about rear extension outcomes in Sefton.

533 real decisions·January 2020 to August 2026·Updated August 2026
90.4%
Approval Rate
533
Decisions
482
Approved
51
Refused
90.4% approved. But 51 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 Sefton.

TypeDecisionsRate
Wraparound Extension41
100.0%
Hip-to-Gable Conversion46
100.0%
Conservatory387
97.7%
Side Extension218
96.3%
Annex41
95.1%
Loft Conversion76
94.7%
Front Extension36
94.4%
Extension (General)1,873
93.5%
Dormer485
92.8%
Garage / Parking927
91.2%
Outbuilding296
90.5%
Rear Extension533
90.4%
New Build332
85.2%
Basement41
82.9%
Flat Conversion84
72.6%
Change of Use (Residential)515
71.8%
HMO60
33.3%
See how this applies to your postcode →

What the data tells us

1
90.4% of rear extension applications in Sefton get approved. That means 51 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

51 rear extension applications in Sefton 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 Sefton planning data

Nearby councils rear extension data

Methodology: Based on 533 planning decisions classified as rear extensions in Sefton, 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 Sefton Council's public planning portal. Full methodology →
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