Data-backed planning intelligence · 3,290,000+ decisions analysed across England

Most Common Planning Applications in Hertsmere

Not all planning applications are created equal. The gap between the highest and lowest approval project type in Hertsmere is 18.7% — that's the difference between near-certainty and a coin flip. What you build matters as much as where you build it.

3,948 real decisions·16 project types·Updated June 2026
100.0%
Safest: HMO
81.3%
Lowest: New Build
18.7%
Spread
16
Types ranked

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All 16 project types ranked

#TypeDecisionsApprovedRefusedRate
1HMO21210
100.0%
2Flat Conversion22220
100.0%
3Front Extension1511438
94.7%
4Wraparound Extension103976
94.2%
5Basement31292
93.5%
6Hip-to-Gable Conversion13712710
92.7%
7Garage / Parking49444846
90.7%
8Dormer47543144
90.7%
9Extension (General)73658
89.0%
10Change of Use (Residential)63567
88.9%
11Outbuilding14312617
88.1%
12Conservatory15313320
86.9%
13Side Extension33028446
86.1%
14Rear Extension1,2061,037169
86.0%
15Loft Conversion947816
83.0%
16New Build917417
81.3%
See how this applies to your postcode →

These are council averages. Your property is specific.

A hmo application has a 100.0% approval rate. New Build? Just 81.3%.
Check your postcode to see what actually happens near your address.

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What the data tells us

1
The range is massive: 81.3% to 100.0%. Choosing the right project type — or framing your application correctly — can dramatically affect outcomes.
2
Visibility drives scrutiny. Project types that change the external appearance — dormers, loft conversions, hip-to-gable — face more resistance than those that don't. The more visible your proposal, the more carefully it needs designing.
3
These are council-wide averages. Your ward, your street and your immediate neighbours all shift the odds. The comparable decisions near your property are the best indicator of outcome.

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

498 planning applications in Hertsmere 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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More Hertsmere planning data

Methodology: Classifies 3,948 decisions in Hertsmere into residential project types using keyword matching against proposal descriptions (matching generate_site_data.py subtype rules). A single application may appear in multiple categories. Data from Hertsmere Council's public planning portal, January 2020 to present. Full methodology →
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