Conservatory replacement extensions across Welwyn Garden City
Planning a conservatory replacement in Welwyn Garden City? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in Welwyn Garden CityFrom £21,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsAL6, AL7, AL8, AL10
When a conservatory replacement makes sense
- Older uPVC conservatories near the end of their life
- Homes where the conservatory sits unused
- Conservatories that are too hot or too cold
Planning rules that apply in Welwyn Garden City
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Working in Welwyn Garden City
Postcode districts we cover around Welwyn Garden City include AL6, AL7, AL8, AL10. The same team covers Hatfield (3 miles), Hertford (6 miles), St Albans (6 miles), Harpenden (6 miles), all within easy reach.
The East of England mixes market-town terraces, inter-war semis and modern estates. Clay soils are common in parts of the region, which can affect foundation design.
Guide prices for Welwyn Garden City
These guide figures apply our East of England adjustment (×1.06) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Welwyn Garden City: £1,960 to £3,710 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 3.3 m 10 m² | £21,000 – £25,500 | £22,500 – £29,500 | £29,000 – £37,500 |
| 3.5 m × 4 m 14 m² | £27,000 – £33,000 | £31,500 – £41,000 | £40,500 – £52,000 |
| 4 m × 5 m 20 m² | £39,000 – £47,000 | £45,500 – £58,500 | £58,000 – £74,500 |
Includes removal of the old conservatory. Reusing existing foundations is only possible after investigation.
Try the guide-price tool to see a range for your own size and finish.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Welwyn Garden City home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Welwyn Garden City
Do you cover all of Welwyn Garden City?
Yes. We cover Welwyn Garden City and the surrounding parts of Hertfordshire. Site visits are free and there is no obligation.
Do I need building regulations approval in Welwyn Garden City?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Welwyn Garden City, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Is it worth replacing a conservatory with an extension?
If the conservatory is unusable for much of the year, usually yes. A solid extension gives a heated room that counts as proper living space. Our guide range is about £1,960 to £3,710 per m² including VAT, including removal.
Can I keep the existing base?
Sometimes, but conservatory bases are often too shallow for solid walls. Trial holes tell us before we confirm the price.
Book a free site visit in Welwyn Garden City
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.