Side Extension approval rate in Hillingdon
Hillingdon approved 71.9% of side extension applications, based on 4,912 decisions analysed.
Last updated: September 2026
71.9%
side extension approval rate
4,912
Side Extension decisions
3,532
Approved
1,380
Refused
77.9%
Hillingdon overall
Side Extension applications are refused more often than the Hillingdon average (77.9%), suggesting the council scrutinises these projects more closely.
How side extension compares in Hillingdon
Side Extension
71.9%
Hillingdon all applications
77.9%
Planning a side extension in Hillingdon?
71.9% 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 →
✓ Nearest comparable side extension decisions
✓ Refusal triggers specific to your area
✓ PDF report for your architect
Planning professional? PlanningLens runs refusal alerts and evidence packs for Hillingdon and any other published UK council — see the data services →
Other project types in Hillingdon
78.6%
81.9%
79.4%
81.1%
84.2%
83.8%
81.4%
66.4%
76.9%
73.7%
82.6%
74.3%
85.6%
57.7%
42.0%