Chiswick · W4
House Extensions in Chiswick
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.
House Extensions in Chiswick: what to know locally
High-value Victorian and Edwardian terraces and semis, including the Bedford Park estate and the grid streets off Chiswick High Road.
Chiswick properties carry high values, so the specification expectation is correspondingly high — sash window matching, proper brick selection and detailing that stands up to close inspection. Much of the area sits in conservation designation.
Planning authority: Hounslow Council. Hounslow applies strict conservation controls across much of Chiswick, and Bedford Park in particular has detailed design guidance. Anything affecting the front elevation almost always needs permission.
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.
Other work we do in Chiswick
House Extensions nearby
House Extensions in Chiswick — questions
Do you cover Chiswick?
Yes — Chiswick and the W4 postcodes are part of our core working area, along with Acton, Hammersmith, Ealing. Being local means a site visit within days rather than weeks.
Which council handles planning for Chiswick?
Hounslow Council. Hounslow applies strict conservation controls across much of Chiswick, and Bedford Park in particular has detailed design guidance. Anything affecting the front elevation almost always needs permission.
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.
House Extensions in Chiswick?
Tell us about the property and what you have in mind. We will come out, measure it properly, and put a written itemised quote in front of you.
We reply to every quote request within 24 hours.