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Rear Extension Approval Rates in North Hertfordshire

Rear extensions are the bread and butter of UK planning — and one of the most common reasons homeowners face a refusal. Here's what 473 real decisions tell us about rear extension outcomes in North Hertfordshire.

473 real decisions·January 2020 to October 2026·Updated October 2026
93.9%
Approval Rate
473
Decisions
444
Approved
29
Refused
93.9% approved. But 29 refused since 2020. Each refusal cost the homeowner time and money on drawings and application fees. Understanding your local data before you apply is the difference between confidence and a costly gamble.

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Why rear extension approval rates matter

Rear extensions sit in the middle of the pack nationally. They're common enough that councils have clear precedent — but that cuts both ways. If your neighbours have been refused, that precedent works against you too.

These are council averages. Your property is specific.

Two houses on the same street can get different outcomes.
Check your postcode to see what actually happens near your address.

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How rear extensions compare to other project types

Not all applications are treated equally. Here's how rear extensions stack up against other common projects in North Hertfordshire.

TypeDecisionsRate
Outbuilding171
94.7%
Rear Extension473
93.9%
Conservatory114
93.9%
Side Extension269
93.7%
Wraparound Extension38
92.1%
Change of Use (Residential)83
91.6%
Garage / Parking414
90.1%
Front Extension131
90.1%
Hip-to-Gable Conversion25
88.0%
Loft Conversion91
87.9%
Dormer154
87.7%
New Build165
83.0%
Extension (General)47
83.0%
Annex31
80.6%
See how this applies to your postcode →

What the data tells us

1
93.9% of rear extension applications in North Hertfordshire get approved. That means 29 homeowners since 2020 have been refused. Not terrible odds, but not a foregone conclusion.
3
Council averages are starting points, not guarantees. The decisions that matter most are the comparable ones near your specific property — because planning officers look at precedent, character and the immediate context of your street.

Before you spend £5,000+ on architects and drawings

29 rear extension applications in North Hertfordshire have been refused since 2020. Many of those homeowners had already paid for drawings and application fees. A free, property-specific report shows you what gets approved — and what gets refused — near your property.

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Free · Property report emailed in minutes · Based on 3,850,000+ real decisions

More North Hertfordshire planning data

Methodology: Based on 473 planning decisions classified as rear extensions in North Hertfordshire, January 2020 to October 2026. Classification uses keyword matching against proposal descriptions (matching generate_site_data.py rules). A single application may appear in multiple categories. Approval rate = approved / (approved + refused). Pending, withdrawn and invalid applications excluded. Data from North Hertfordshire Council's public planning portal. Full methodology →
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