Timber frame extensions in Chelmsford: design, approvals and build
If you live in Chelmsford and want more space without moving, a timber frame extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in ChelmsfordFrom £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 districtsCM1, CM2
What is included
- Breathable wall build-up with insulation
- Foundations, often lighter than masonry
- Fire and acoustic details where needed
- Cladding, render or brick slip finish
- Frame design and structural calculations
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.
Guide prices for Chelmsford
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 Chelmsford: £1,860 to £3,600 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 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 |
Try the guide-price tool to see a range for your own size and finish.
Do I need planning permission in Chelmsford?
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.
The planning position for a specific Chelmsford address depends on its history and any designations, which is why we check it at the first visit.
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).
Covering Chelmsford
Our survey diary covers Chelmsford, including CM1, CM2. Neighbouring towns we cover include Billericay (8 miles), Witham (9 miles), Maldon (9 miles), Wickford (9 miles).
Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
How the project works
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 Chelmsford home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Chelmsford
Will my neighbours in Chelmsford be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Chelmsford, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Chelmsford?
Yes. We cover Chelmsford and the surrounding parts of Essex. Site visits are free and there is no obligation.
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 Chelmsford
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.