Side extension planning approval in Hillingdon
Based on decisions in the last 5 years, as of 12 Jun 2026.
Of 493 side extension planning applications decided by Hillingdon in the last 5 years, 75% were approved. This is the council's track record for this kind of work. It is a useful gauge before you apply, not a guarantee for any one application.
Other work in Hillingdon
- Extension : 81% approved (2,340 decided)
- Rear extension : 82% approved (1,666 decided)
- Roof / fenestration : 84% approved (1,090 decided)
- Demolition : 81% approved (882 decided)
- Loft conversion : 82% approved (812 decided)
- Outbuilding / garden room : 83% approved (506 decided)
- Two-storey extension : 69% approved (452 decided)
- Porch : 77% approved (356 decided)
Method
Approval rate = approved ÷ (approved + refused) over the public planning decisions we hold for Hillingdon, matched to a type of work from the application description. We lead with the last few years so the figure reflects how Hillingdon decides today, with the longer record as context. A rate is only shown once there are enough decided applications for it to be reliable. We publish aggregate figures only, never an individual application or applicant name. Read the full method and limits.