West & North-West London
Extensions that actually fit the house
Rear, side return, wraparound or double storey — we handle the build from foundations to final decoration, including the steel, the drainage diversion and the building control sign-off.
Most West London extensions are built on Victorian or Edwardian stock, which means party walls, shallow existing foundations and drain runs in awkward places. We dig trial holes before quoting so the price reflects what is actually under the ground rather than what we hoped was there. Structural steel is calculated by an engineer, not guessed, and we handle the Party Wall notices and building control from the start.
What the work covers
- Foundations, underpinning and structural steel
- Party Wall notices and awards
- Drainage diversion and new soil runs
- Roofing — flat, pitched, lantern or glazed
- First and second fix electrics and plumbing
- Plastering, flooring and full decoration
What it costs
Most single-storey rear extensions in this part of London land between £2,200 and £3,000 per square metre depending on glazing, groundworks and finish. A proper site visit is the only way to price it honestly.
House Extensions by area
Each area has its own planning position and housing stock. Pick yours for the local detail.
Other services
House Extensions — common questions
Do I need planning permission for an extension?
Many single-storey rear extensions fall under permitted development, but limits differ for terraced, semi-detached and detached homes, and permitted development rights are often removed in conservation areas. We check the specific property against the local authority's records before quoting.
How long does an extension take?
A straightforward single-storey rear extension is usually 10 to 14 weeks on site. Double storey or anything involving underpinning runs longer. The written quote carries a programme with dates, not a vague estimate.
Will I need a Party Wall agreement?
If you are building on or next to the boundary with a neighbour, or excavating within three metres of their foundations, then yes. We serve the notices and manage the process — it needs two months' lead time, so we start it early.
Can I stay in the house during the work?
Usually yes for a rear extension, since the existing wall stays up until late in the build. We seal the work area, keep dust down and agree in advance which services get interrupted and when.
Thinking about a project?
Send a few details and we will come out, measure properly and put a written, itemised quote in front of you.
We reply to every quote request within 24 hours.