Harrow timber frame extensions, designed and built
From the first sketch to final sign-off, we plan and build timber frame extensions in Harrow and the surrounding Greater London area.
- Guide price in HarrowFrom £27,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsHA0, HA1, HA2, HA3, HA7
Will the council need to approve it?
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 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.
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).
Covering Harrow
Across HA0, HA1, HA2, HA3, HA7, HA9, we can visit, measure and advise. The same team covers Wealdstone (1 mile), Wembley (2 miles), Pinner (2 miles), Northolt (3 miles), all within easy reach.
For homes towards Hertfordshire, Bushey is around 5 miles away. London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
Guide prices for Harrow
These guide figures apply our London adjustment (×1.3) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Harrow: £2,280 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £27,000 – £33,000 | £31,500 – £41,500 | £40,500 – £53,500 |
| 4 m × 5 m 20 m² | £45,500 – £55,000 | £53,000 – £69,000 | £67,500 – £88,500 |
| 5 m × 6 m 30 m² | £68,000 – £82,000 | £79,500 – £103,500 | £101,000 – £133,000 |
For a figure based on your own dimensions, use our guide-price tool.
What we take care of
- Fire and acoustic details where needed
- Foundations, often lighter than masonry
- Cladding, render or brick slip finish
- Breathable wall build-up with insulation
- Frame design and structural calculations
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Timber frame extension questions answered
Who do I contract with for a timber frame extension in Harrow?
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 you cover all of Harrow?
Yes. We cover Harrow and the surrounding parts of Greater London. Site visits are free and there is no obligation.
How long does a timber frame extension take to build in Harrow?
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 £2,280 to £4,420 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 Harrow
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.