Planning Permission in Hertsmere
Non-Metropolitan District in East of England · Last updated April 2026
Hertsmere is a south Hertfordshire borough on the London boundary, covering Borehamwood (home to Elstree Studios), Bushey, Potters Bar, Radlett, and Shenley. With approximately 80% of the borough designated as Green Belt, Hertsmere is one of the most constrained authorities in the county.
The borough's 16 conservation areas and 317 listed buildings reflect the historic villages and town centres that pre-date the 20th-century suburban growth. The proximity to London and the M25 creates intense development pressure that the Green Belt and heritage designations help to manage.
Hertsmere's planning service balances the needs of a commuter borough with strong Green Belt protection and heritage conservation.
Planning a project in Hertsmere? Start here.
Enter your address to check your permitted development rights, conservation area status, and Article 4 restrictions specific to Hertsmere.
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What can I build in Hertsmere?
| Project type | Likely permitted development | May need planning permission | Likely needs planning permission |
|---|---|---|---|
| Rear extension (single storey) | Most of Hertsmere outside protected zones | Properties near boundaries or Green Belt fringe areas | Conservation areas (16), listed buildings |
| Rear extension (two storey) | Most of Hertsmere outside protected zones, if within 3m limit | Check distance to boundary ≥7m or Green Belt fringe areas | Conservation areas (16), listed buildings |
| Side extension | Detached houses outside protected zones | Semi-detached properties (half-width rule) | Conservation areas (16), listed buildings |
| Loft conversion (dormer) | Houses outside conservation areas | Properties on prominent corners or Green Belt fringe areas | Conservation areas, listed buildings, flats |
| Loft conversion (Velux/rooflight) | Most of Hertsmere | Front-facing rooflights in conservation areas | Listed buildings |
| Outbuilding / garden office | Most of Hertsmere outside protected zones, if within size/height limits | Large outbuildings covering >50% of garden | Conservation areas (side or front), listed buildings, Green Belt |
| Porch | Most properties if within 3m² and 3m height | Properties near highway boundary | Conservation areas with restrictions, listed buildings |
| Solar panels | Most properties (roof-mounted) | Panels protruding beyond roofline | Listed buildings, conservation areas (if visible from road) |
| Driveway / hard standing | If using permeable surfacing | Non-permeable surfacing over 5m² | Conservation areas with specific restrictions |
| Garage conversion | Most of Hertsmere (internal works) | If changing external appearance significantly | Listed buildings |
This is general guidance based on Hertsmere's planning constraints. Your specific property may differ — use our free PD checker to get a result tailored to your address.
Permitted development in Hertsmere
Hertsmere has no Article 4 directions, so most properties outside conservation areas retain full PD rights. However, with approximately 80% of the borough in the Green Belt, the main constraint for many householders is Green Belt policy. Extensions in the Green Belt must be proportionate to the original dwelling. In the urban areas of Borehamwood, Bushey, and Potters Bar, standard PD rights apply for most householder works.
What Hertsmere expects from your project
Local design guidance
Local Plan: Hertsmere Local Plan
Hertsmere's development plan currently relies on saved policies from its 2003 Local Plan — one of the oldest in England. The district is almost entirely surrounded by London and the M25, with most of its land within Metropolitan Green Belt. Development is concentrated in Borehamwood, Potters Bar, Radlett and Bushey.
Emerging / replacement plan
Hertsmere is preparing a new Local Plan. A Regulation 19 Pre-Submission plan was consulted on in 2023, with submission to the Planning Inspectorate expected in 2024–2025 and adoption targeted for 2026.
11 Article 4 directions
Hertsmere has applied Article 4 directions to 11 areas, which remove certain permitted development rights in those zones. Use our free checker to see if your property is affected.
93.4% approval rate
Hertsmere approves 93.4% of planning applications, above the national average of 86.9%. Well-designed residential applications in this area tend to have a good chance of success.
Conservation areas in Hertsmere
16 designated conservation areas
Hertsmere's 16 conservation areas protect the historic village centres and key heritage areas. Elstree village, Bushey High Street, Radlett, and Shenley each have distinct conservation areas. Bushey has particular significance as an artists' colony — the Bushey Museum records the area's artistic heritage. Aldenham village and the surrounding countryside retain their rural Hertfordshire character despite the proximity to London.
Article 4 directions in Hertsmere
11 Article 4 direction areas
Listed buildings in Hertsmere
There are 317 listed buildings in Hertsmere. If your property is listed, permitted development rights are significantly restricted. Most external and many internal alterations will require listed building consent, which is separate from planning permission. Always check with Hertsmere's conservation team before starting any work on a listed property.
Planning application statistics
Year ending September 2025 | Source: MHCLG planning application statistics
Hertsmere received 826 planning applications and decided 739 in the year ending September 2025. The approval rate of 93.4% is above the national average of 86.9%. Major applications are expected to be decided within 13 weeks, while householder and other non-major applications have an 8-week target. The “in time” figures include decisions made within agreed extensions of time.
Hertsmere manages a moderate caseload with a 93.4% approval rate and 95.9% delegation rate. The 91.8% on-time rate for householder decisions and 826 applications received show efficient processing for a constrained London-fringe borough.
If your project complies with permitted development rules, you don't need to worry about approval rates — a Lawful Development Certificate is a factual assessment, not a judgment call.
Recent planning applications in Hertsmere
Browse what's been approved near you
Seeing what similar projects have been approved near your property can help you understand what Hertsmere expects in terms of scale, materials, and design. It's also useful for gauging how quickly the council processes applications.
Search planning applications on Hertsmere's portal →Data from MHCLG planning application register. Search for householder applications (H01/H02) to see extensions and loft conversions in your area.
Housing delivery in Hertsmere
Housing Delivery Test 2023 measurement | Source: MHCLG
Hertsmere delivered 882 homes against a requirement of 1,922 over the three-year measurement period, giving a Housing Delivery Test score of 46%. This is well below the 75% threshold, which triggers the most significant consequence: the “presumption in favour of sustainable development” (also called the “tilted balance”). This means planning applications for housing should be approved unless the harm would significantly and demonstrably outweigh the benefits. For homeowners, this is a strong signal — Hertsmere is under considerable pressure to approve housing, making it one of the more favourable environments for residential planning applications in England.
Lawful Development Certificates in Hertsmere
A Lawful Development Certificate (LDC) is formal confirmation from Hertsmere that your project is lawful under permitted development rules. It is not legally required before you build, but it is the only official document that proves your project did not need planning permission. Most solicitors will ask for one when you come to sell, remortgage, or insure your property.
Hertsmere decided 498 householder applications in the year ending september 2025. Their 8-week performance of 91.8% is below the national average of 93%, so LDC applications may take longer than the 8-week target. LDC applications follow the same 8-week statutory determination period as householder planning applications.
How to apply for an LDC in Hertsmere
You can apply for a Lawful Development Certificate through the Planning Portal or directly through Hertsmere's website. You will need to submit:
- A completed application form (available on the Planning Portal)
- A site location plan at 1:1250 or 1:2500 scale
- Existing and proposed floor plans and elevations
- A written description of the proposed works and how they comply with the GPDO 2015
- The application fee of £258
Hertsmere must issue a decision within 8 weeks. If the application is approved, the certificate is a permanent legal record that the development is lawful. If refused, you can appeal to the Planning Inspectorate or amend your project and reapply.
Need help preparing your LDC application?
Our Permitted Development Certificate Report gives you a full PD eligibility assessment, property constraints check, and application checklist tailored to your address and project — so you can apply with confidence.
Check your permitted development rights
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£49Hertsmere Local Authority Report
Approval rates, decision patterns, Article 4 directions, fees & timelines, and council-specific tips for Hertsmere.
Pre-application advice in Hertsmere
Hertsmere offers a pre-application advice service. The fee for householder pre-app advice is Varies by proposal type.
Pre-app advice is worth paying for if your project is borderline, your property is in a conservation area, or your home is a listed building.
Think your project might be permitted development?
Check in 2 minutes with our free tool — no sign-up needed.
Check your PD rights now →Hertsmere offers pre-application advice for householder and larger developments.
Planning fees and timelines in Hertsmere
| Application type | Fee | Typical timeline |
|---|---|---|
| Householder planning application | £528 | 8 weeks |
| Full planning permission | £610 per dwelling | 8-13 weeks |
| Lawful Development Certificate (proposed) | £264 | 6-8 weeks |
| Lawful Development Certificate (existing) | £298 | 6-8 weeks |
| Listed building consent | Free | 8 weeks |
| Prior approval | £120 | 56 days |
| Discharge of conditions | £145 per request | 8 weeks |
| Non-material amendment | £44 | 28 days |
Fees are set nationally and correct as of April 2026. Pre-application fees are set by Hertsmere and may change. Building regulations fees are separate — see the building control section below.
Building regulations in Hertsmere
Building regulations approval is separate from planning permission. Most extensions, loft conversions, and structural alterations need building regs approval even if they don't need planning permission.
Building control in Hertsmere is provided by Hertsmere Building Control. You can also use a private approved inspector instead of the council's service.
Building control contact
Hertsmere planning department
Your building project checklist for Hertsmere
- Check if your property is in a conservation area — Hertsmere has 16 conservation areas. Use our free checker or see the list above.
- Check for Article 4 directions at your address — Hertsmere has 11 Article 4 areas. Check your address.
- Check if your property is listed — search the Historic England list.
- Use our free PD checker to see if your project qualifies as permitted development — Check now.
- Consider a Lawful Development Certificate if PD applies — it protects you when selling. Learn more about LDCs or get your PD Certificate Report.
- Consider pre-application advice if planning permission is needed — see the pre-application section above.
- Check building regulations — most extensions and loft conversions need building regs approval even if they don't need planning permission.
- Check Party Wall Act obligations if building near a boundary — read our Party Wall guide or use our free Party Wall tool.
- Notify your home insurer about planned building work.
- Get at least 3 quotes from builders and check their credentials.
Nearby planning authorities
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