Side Extension approval rate in Hillingdon

Hillingdon approved 70.9% of side extension applications, based on 4,767 decisions analysed.

Last updated: March 2026

70.9%

side extension approval rate

4,767

Side Extension decisions

3,378

Approved

1,389

Refused

78.9%

Hillingdon overall

Side Extension applications are refused more often than the Hillingdon average (78.9%), suggesting the council scrutinises these projects more closely.

How side extension compares in Hillingdon

Side Extension (4,767 decided)

70.9%

Hillingdon all applications (30,009 decided)

78.9%

Planning a side extension in Hillingdon?

70.9% get approved — but the odds vary by street. Your Pro Report 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

Get Hillingdon Pro Report — £79

Less than one set of revised drawings.