Data-backed planning intelligence · 3,780,000+ decisions analysed across England

Rear Extension Approval Rates in Hounslow

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 26,811 real decisions tell us about rear extension outcomes in Hounslow.

26,811 real decisions·January 2020 to August 2026·Updated August 2026
85.0%
Approval Rate
26,811
Decisions
22,783
Approved
4,028
Refused
85.0% approved. But 4,028 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.

Check Planning Approval Patterns in Hounslow

See your ward's approval rate and nearby planning decisions — free and instant.

Check My Postcode

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.

Check My Postcode

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 Hounslow.

TypeDecisionsRate
Conservatory1,940
94.7%
Extension (General)3,055
92.9%
New Build4,808
90.3%
Basement1,496
90.0%
Dormer1,432
89.9%
Loft Conversion12,130
89.7%
Garage / Parking8,772
88.9%
Wraparound Extension1,518
88.9%
Side Extension7,853
88.1%
Hip-to-Gable Conversion3,282
85.5%
Rear Extension26,811
85.0%
Front Extension1,046
82.9%
Change of Use (Residential)3,110
82.7%
Outbuilding4,207
80.9%
Flat Conversion1,420
73.0%
Annex108
69.4%
HMO353
48.7%
See how this applies to your postcode →

What the data tells us

1
85.0% of rear extension applications in Hounslow get approved. That means 4,028 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

4,028 rear extension applications in Hounslow 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.

Check my postcode
Free · Property report emailed in minutes · Based on 3,780,000+ real decisions

More Hounslow planning data

Nearby councils rear extension data

Methodology: Based on 26,811 planning decisions classified as rear extensions in Hounslow, 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 Hounslow Council's public planning portal. Full methodology →
Check planning approval patterns in Hounslow — Free