Name: Extension Builder
Brand: HaMuch
SKU: extension-renovation
Rating: 4.73 (20 reviews)

Find affordable City Of Westminster extension builders

Prices range from cheapest £38/hour and £241/day (Buci builders ltd) to £86/hour and £448/day (Bspec Ltd) - average £47/hr and £290/day

HaMuch is Excellent

Local City Of Westminster extension builders & latest jobs

"Underpin a building" - N7, job posted 23/08/26

"Single storey extension" - SW18, job posted 23/03/26

"Concrete foundation" - W1T, job posted 16/10/25

"A 8 meter by 1 story high wall to removed clear way and rebuild" - SW4, job posted 18/08/25

"Side return extension" - NW10, job posted 14/08/25

"We have a long list of customers that need only a builder that can fit conservatory. We don’t need supplier. Please contact us if you can help. Thanks" - NW10, job posted 10/07/25

"To divide a room" - SW2, job posted 08/07/25

"Fully extend with side return and renovate dated Victorian house with loft added. Size is 100m2 currently to 160m2 on completion." - E5, job posted 19/06/25

"Need an extension builder" - N4, job posted 18/05/25

"Basement conversion" - LAMBETH, job posted 02/05/25

"Basement conversion" - E5, job posted 27/04/25

"Loft conversion" - W12, job posted 21/04/25

"Loft conversion" - W12, job posted 20/04/25

"RSJ re-installation" - N16, job posted 10/04/25

"Extension to lower ground area." - SW9, job posted 28/03/25

"Flat roof extension" - E5, job posted 18/03/25

"Single storey extension" - BALHAM, job posted 26/02/25

"Two storey extension" - HERNE HILL, job posted 12/01/25

"Loft conversion" - W12, job posted 23/10/24

"Flat roof extension for a period mews terraced house. We'd like a bedroom extension with full bathroom and a roof top terrace. Footprint is roughly 8.5m x 6m." - W6, job posted 06/10/24

What are the best ways to avoid problems when paying the Extension Builder?

The most important thing is do avoid handing over cash or paying large sums in advance. Be wary of paying cash for a cheaper job, i.e. to avoid VAT, you may be going down a slippery slope of not doing things properly which may eventually mean your job is also not done properly.

Agree when you intend to pay, ideally after you are satisfied with the completed job. If it is a big job agree a schedule of staged payments which is fair to both parties.

To avoid bad tradespeople and to ensure you can find them should they not answer a mobile;

Get proper contact details and check them yourself
Check if the company is verified on the Companies House website
Get phone details, ideally a land line or 0800 number and check it
Get a physical office address

Before the job starts should I agree standards of quality and behaviour?

Get quotes in writing by email or in person if possible. Getting quotes online or by text is ok (make sure you accept the offer by replying). For large projects make a written agreement, schedule of works and snagging plans as part of a working document. Also;

Agree expected quality of workmanship and materials in advance
When will work start and when will project be finished, what happens if project over runs ?
How long is the guarantee on work and materials eg 12 months
Discuss onsite behaviour in advance (no smoking, swearing or using mobile phones for non-work purposes)
Agree that your Extension Builder will remove all debris and rubbish and what level of tidying up you want after job

Compare City Of Westminster extension builders rates

Compare City Of Westminster extension builders rates (excluding VAT or callout charges)
Location in UK	Hourly Rate	Daily Rate
Extension Builders near London	£45	£274
Extension Builders near Camden Town	£44	£277
Extension Builders near Belgravia	£44	£276
Extension Builders near Chelsea	£44	£276
Extension Builders near Lambeth	£44	£275
Extension Builders near Kensington	£44	£277
Extension Builders near Islington	£45	£276
Extension Builders near Fulham	£44	£277
Extension Builders near Camberwell	£44	£276
Extension Builders near Bethnal Green	£45	£276

Job estimates from extension builders near you

Whether you’re looking to extend your kitchen with a side return extension or you want to convert your basement into a liveable space, read our cost guides to get an idea of how much each project costs before getting a more accurate quote from our database of reliable tradespeople.

Build a timber frame extension - £26,200

Garden office - £10,200

Granny annexe - £87,200

Build a flat roof extension - £22,200

Convert a Garage - £16,200

Hip to gable loft conversion - £42,200

Convert a bungalow loft - £29,200

Build a dormer loft conversion - £42,200

Build a swimming pool - £81,200

Build a Mansard loft conversion - £52,200

Concrete foundations - £6,450

Underpin a building - £17,700

Two storey extension - £88,300

Convert a basement - £39,750

Side return extension - £43,750

Loft conversion - £35,625

Garage - £18,700

Single storey extension - £59,000

Outbuilding - £10,200

Install an RSJ - £2,400

Build a kitchen extension - £42,200

More extensions & conversions cost guides...

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