Side Extension approval rate in Hertsmere
Hertsmere approved 87.9% of side extension applications, based on 380 decisions analysed.
Last updated: September 2026
87.9%
side extension approval rate
380
Side Extension decisions
334
Approved
46
Refused
87.5%
Hertsmere overall
Side Extension applications are approved at roughly the same rate as the Hertsmere average (87.5%).
How side extension compares in Hertsmere
Side Extension
87.9%
Hertsmere all applications
87.5%
Planning a side extension in Hertsmere?
87.9% 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 Hertsmere →
✓ 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 Hertsmere and any other published UK council — see the data services →
Other project types in Hertsmere
86.6%
91.8%
91.6%
89.7%
88.3%
95.2%
93.2%
95.3%
82.8%
83.3%
89.7%
100.0%
93.8%
100.0%
100.0%