Witham over-garage extensions, designed and built
We design and build over-garage extensions for houses in Witham, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in WithamFrom £25,000 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsCM8
Planning rules that apply in Witham
In England any side extension over one storey, including a room built over a side garage, needs a householder planning application. The fee is £548 from 1 April 2026 and councils aim to decide within 8 weeks.
The planning position for a specific Witham 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.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Over-garage extension prices in Witham
Prices below are for Witham, using the East of England factor of ×1.06. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Witham: £1,910 to £3,600 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £25,000 – £31,500 | £26,500 – £34,500 | £34,000 – £43,500 |
| Over a large single garage 16 m² | £30,500 – £37,500 | £35,500 – £46,000 | £45,500 – £58,000 |
| Over a double garage 24 m² | £45,500 – £56,000 | £53,000 – £69,000 | £68,500 – £86,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
What we take care of
- Opening into the existing first floor
- Design and householder planning application
- Structural survey of garage walls and foundations
- Insulation, electrics, heating and finish
- Strengthening or rebuilding the garage walls if needed
- New floor structure, walls and roof
Extensions in and around Witham
We cover Witham and the postcode districts CM8. Nearby, we also take on projects in Maldon (5 miles), Braintree (7 miles), Chelmsford (9 miles), Colchester (13 miles).
Sudbury, in Suffolk, is roughly 17 miles from Witham and also on our list. Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
Our process, step by step
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Witham
Do I need building regulations approval in Witham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does an over-garage extension take to build in Witham?
On site, typically 12 to 18 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Witham, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Does building over a garage need planning permission?
In England and the rest of the UK, adding a storey over a side garage almost always needs a planning application, because two-storey side extensions are outside permitted development.
How much does a room over a garage cost?
Our guide range is about £1,910 to £3,600 per m² including VAT. A single-garage room of about 12 m² usually costs £26,500 to £34,500 at standard spec, more if the garage needs rebuilding.
Book a free site visit in Witham
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.