Planning Permission in Welwyn Hatfield
Non-Metropolitan District in East of England · Last updated April 2026
Welwyn Hatfield is a Hertfordshire borough centred on two contrasting towns: Welwyn Garden City — the second garden city, founded in 1920 — and Hatfield, a medieval town transformed by the de Havilland aircraft factory and post-war new town development. With 10 conservation areas and 429 listed buildings, the borough combines garden city heritage with older Hertfordshire character.
Extensive Green Belt covers much of the borough, separating the two towns and protecting the surrounding countryside. The borough has no Article 4 directions, though Welwyn Garden City has its own design guidance through the heritage of its garden city principles.
The borough manages planning applications across diverse character areas, from the Arts and Crafts garden city to modern development around Hatfield's University of Hertfordshire campus.
Planning a project in Welwyn Hatfield? Start here.
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What can I build in Welwyn Hatfield?
| Project type | Likely permitted development | May need planning permission | Likely needs planning permission |
|---|---|---|---|
| Rear extension (single storey) | Most of Welwyn Hatfield outside protected zones | Properties near boundaries or Green Belt fringe areas | Conservation areas (10), listed buildings |
| Rear extension (two storey) | Most of Welwyn Hatfield outside protected zones, if within 3m limit | Check distance to boundary ≥7m or Green Belt fringe areas | Conservation areas (10), listed buildings |
| Side extension | Detached houses outside protected zones | Semi-detached properties (half-width rule) | Conservation areas (10), 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 Welwyn Hatfield | Front-facing rooflights in conservation areas | Listed buildings |
| Outbuilding / garden office | Most of Welwyn Hatfield 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 Welwyn Hatfield (internal works) | If changing external appearance significantly | Listed buildings |
This is general guidance based on Welwyn Hatfield's planning constraints. Your specific property may differ — use our free PD checker to get a result tailored to your address.
Permitted development in Welwyn Hatfield
Welwyn Hatfield has no Article 4 directions, so most properties outside conservation areas retain full PD rights. The extensive Green Belt between and around the two towns is the main constraint. In Welwyn Garden City, the original garden city design principles influence planning decisions even outside the formal conservation areas. Hatfield's new town areas generally have straightforward PD entitlements with generous gardens.
What Welwyn Hatfield expects from your project
Local design guidance
Supplementary Design Guidance (SDG)
Local Plan: Welwyn Hatfield Local Plan 2016–2036
Welwyn Hatfield Borough adopted its Local Plan in October 2023 after a very lengthy examination process. The plan provides for over 12,000 new homes in the two new towns of Welwyn Garden City and Hatfield, with complex policies managing their heritage as planned garden cities alongside the need for significant new housing growth.
Emerging / replacement plan
The Local Plan was recently adopted. The council will monitor delivery and undertake a review at the appropriate stage of the plan period.
Conservation areas in Welwyn Hatfield
10 designated conservation areas
Welwyn Hatfield's 10 conservation areas protect Welwyn Garden City's pioneering garden city design, Hatfield's medieval old town, and surrounding villages. Welwyn Garden City's conservation areas recognise Louis de Soissons' original layout and Arts and Crafts architecture. Hatfield Old Town has a distinct medieval character centred on the medieval palace and church. Village conservation areas like Welwyn, Digswell, and Woolmer Green protect traditional Hertfordshire character.
Article 4 directions in Welwyn Hatfield
5 Article 4 direction areas
Listed buildings in Welwyn Hatfield
There are 429 listed buildings in Welwyn Hatfield. 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 Welwyn Hatfield's conservation team before starting any work on a listed property.
Planning application statistics
Year ending September 2025 | Source: MHCLG planning application statistics
Welwyn Hatfield received 737 planning applications and decided 670 in the year ending September 2025. The approval rate of 86.1% is below 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.
Welwyn Hatfield manages a substantial caseload with a 86.1% approval rate and 98.4% delegation rate. The 97% on-time rate for householder decisions and 737 applications received demonstrate efficient processing.
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 Welwyn Hatfield
Browse what's been approved near you
Seeing what similar projects have been approved near your property can help you understand what Welwyn Hatfield expects in terms of scale, materials, and design. It's also useful for gauging how quickly the council processes applications.
Search planning applications on Welwyn Hatfield'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 Welwyn Hatfield
Housing Delivery Test 2023 measurement | Source: MHCLG
Welwyn Hatfield delivered 1,066 homes against a requirement of 2,036 over the three-year measurement period, giving a Housing Delivery Test score of 52%. 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 — Welwyn Hatfield 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 Welwyn Hatfield
A Lawful Development Certificate (LDC) is formal confirmation from Welwyn Hatfield 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.
Welwyn Hatfield decided 427 householder applications in the year ending september 2025. Their 8-week performance of 97% is above the national average of 93%, which suggests LDC applications are likely to be processed on time. LDC applications follow the same 8-week statutory determination period as householder planning applications.
How to apply for an LDC in Welwyn Hatfield
You can apply for a Lawful Development Certificate through the Planning Portal or directly through Welwyn Hatfield'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
Welwyn Hatfield 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.
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£49Welwyn Hatfield Local Authority Report
Approval rates, decision patterns, Article 4 directions, fees & timelines, and council-specific tips for Welwyn Hatfield.
Pre-application advice in Welwyn Hatfield
Welwyn Hatfield 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?
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Check your PD rights now →Welwyn Hatfield offers pre-application advice for householder and larger developments.
Planning fees and timelines in Welwyn Hatfield
| 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 Welwyn Hatfield and may change. Building regulations fees are separate — see the building control section below.
Building regulations in Welwyn Hatfield
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 Welwyn Hatfield is provided by Welwyn Hatfield Building Control. You can also use a private approved inspector instead of the council's service.
Building control contact
Welwyn Hatfield planning department
Your building project checklist for Welwyn Hatfield
- Check if your property is in a conservation area — Welwyn Hatfield has 10 conservation areas. Use our free checker or see the list above.
- Check for Article 4 directions at your address — Welwyn Hatfield has 5 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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