Building regulations for extensions in Hounslow
We prepare building regulations for extensions for homes in Hounslow, as a stand-alone service or as the first stage of a design and build project.
- Guide price in HounslowFrom £1,150 inc VAT
- Approval routeFull plans or building notice
- Timescale2–5 weeks for drawings
- Postcode districtsTW1, TW2, TW3, TW4, TW5

Covering Hounslow
We cover Hounslow and the postcode districts TW1, TW2, TW3, TW4, TW5, TW7. We also work in nearby Isleworth (1 mile), Heston (1 mile), Richmond (2 miles), Hanworth (3 miles).
West Molesey, in Surrey, is roughly 5 miles from Hounslow and also on our list. 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.
Design and approval fees for Hounslow
These are guide fees for Hounslow, adjusted for London (×1.3) and including VAT. Council application and inspection fees are paid separately.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Building regulations drawings for a simple single-storey extension | £1,150 – £2,350 |
| Standard | Drawings plus structural calculations | £1,650 – £3,400 |
| Premium | Complex or two-storey pack with energy calculations | £2,850 – £4,950 |
Our design fee only. Building control charges are set by your council (or, in England and Wales, a registered building control approver) and quoted separately.
Want a range for your exact size? The guide-price tool takes about a minute.
Planning and approvals in Hounslow
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.
The planning position for a specific Hounslow address depends on its history and any designations, which is why we check it at the first visit.
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.
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).
Who this service is for
- Homeowners using their own builder who need the drawings
- Every extension, whatever the planning route
- Glass-heavy designs that need energy calculations
Building regulations approval and planning permission are separate. A design can have planning consent and still need changes to meet the regulations, which is why we draw for both together.
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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Hounslow
Do I need building regulations approval in Hounslow?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does this take for a Hounslow home?
2–5 weeks for drawings, depending on the council and the complexity of the project.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Hounslow, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who are building control?
Either your local council’s building control team or a registered building control approver. Both inspect the work and issue the completion certificate.
Full plans or building notice?
A full plans application gets the drawings checked before work starts, which we usually recommend for extensions. A building notice is quicker to submit but carries more risk if something needs changing on site.
Book a free site visit in Hounslow
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.