Building regulations for extensions across Isleworth
For Isleworth homeowners we handle building regulations for extensions, with fees agreed in writing before any work starts.
- Guide price in IsleworthFrom £1,150 inc VAT
- Approval routeFull plans or building notice
- Timescale2–5 weeks for drawings
- Postcode districtsTW1, TW3, TW4, TW5, TW7
Will the council need to approve it?
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 Isleworth 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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Covering Isleworth
We cover Isleworth and the postcode districts TW1, TW3, TW4, TW5, TW7, TW8. We also work in nearby Hounslow (1 mile), Heston (2 miles), Richmond (2 miles), Southall (3 miles).
Just over the Surrey border, East Molesey is about 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.
Who this service is for
- Every extension, whatever the planning route
- Glass-heavy designs that need energy calculations
- Homeowners using their own builder who need the drawings
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.
Design and approval fees for Isleworth
Fees below are our Isleworth guide (×1.3, the London factor), including VAT. Council and building control fees are extra.
| 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.
For a figure based on your own dimensions, use our guide-price tool.
From first visit to completion
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
We visit your Isleworth home, measure up, talk through what you want and check the planning position.
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
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Isleworth, 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 do I contract with in Isleworth?
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.
How long does this take for a Isleworth home?
2–5 weeks for drawings, depending on the council and the complexity of the project.
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 Isleworth
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.