Side Extension approval rate in Hillingdon

Hillingdon approved 71.8% of side extension applications, based on 4,872 decisions analysed.

Last updated: August 2026

71.8%

side extension approval rate

4,872

Side Extension decisions

3,497

Approved

1,375

Refused

80.0%

Hillingdon overall

Side Extension applications are refused more often than the Hillingdon average (80.0%), suggesting the council scrutinises these projects more closely.

How side extension compares in Hillingdon

Side Extension (4,872 decided)

71.8%

Hillingdon all applications (30,835 decided)

80.0%

Planning a side extension in Hillingdon?

71.8% get approved, but the odds vary by street. Your Full Planning Analysis shows exactly what gets approved and refused near your property.

✓ Your ward's side extension approval rate
✓ Nearest comparable side extension decisions
✓ Refusal triggers specific to your area
✓ PDF report for your architect

Free planning check for Hillingdon →