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Welwyn Garden City timber frame extensions, designed and built

Our design and build teams take on timber frame extensions in Welwyn Garden City, from the first measured survey through planning and building control to the finished room.

  • Guide price in Welwyn Garden CityFrom £22,000 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
Timber frame extension under construction with OSB sheathing and roof joists

How much does a timber frame extension cost in Welwyn Garden City?

For Welwyn Garden City we adjust our national guide rates by ×1.06, the factor we use for East of England. Figures include VAT; your written quote after the survey replaces them.

Typical rates in Welwyn Garden City: £1,860 to £3,600 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
3 m × 4 m
12 m²
£22,000 – £27,000£26,000 – £34,000£33,000 – £43,500
4 m × 5 m
20 m²
£37,000 – £45,000£43,000 – £56,500£55,000 – £72,500
5 m × 6 m
30 m²
£55,500 – £67,000£65,000 – £84,500£82,500 – £108,500

For a figure based on your own dimensions, use our guide-price tool.

What is included

  • Foundations, often lighter than masonry
  • Frame design and structural calculations
  • Cladding, render or brick slip finish
  • Breathable wall build-up with insulation
  • Fire and acoustic details where needed

Moisture is the enemy of any timber building. We design ventilated cladding cavities, breather membranes and a proper damp-proof course height, and keep the frame dry during construction.

Extensions in and around Welwyn Garden City

Our survey diary covers Welwyn Garden City, including AL6, AL7, AL8, AL10. We also work in nearby Hatfield (3 miles), Hertford (6 miles), St Albans (6 miles), Harpenden (6 miles).

Just over the Bedfordshire border, Luton is about 10 miles away. Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.

Planning and approvals 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.

Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.

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).

From first visit to completion

Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.

  1. Free site visit

    We visit your Welwyn Garden City home, measure up, talk through what you want and check the planning position.

  2. Design and approvals

    We draw the design, agree it with you and handle planning or permitted development checks and building regulations.

  3. Fixed written price

    You receive a written, itemised price and programme. Nothing starts until you are happy with it.

  4. 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

Who do I contract with for a timber frame extension in Welwyn Garden City?

Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.

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.

How long does a timber frame extension take to build in Welwyn Garden City?

On site, typically 8 to 14 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.

Is timber frame cheaper than brick?

It is similar overall. The frame can save time on site, but the cladding choice has a big effect on cost. Our guide range is about £1,860 to £3,600 per m² including VAT.

Does a timber frame extension need planning permission?

The same planning rules apply as for any extension. If the cladding looks different from the house, permitted development’s matching-materials condition may mean an application is needed.

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

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