Name: Extension Builder
Brand: HaMuch
SKU: extension-renovation
Rating: 4.7 (20 reviews)

Find local affordable SL1 extension builders

Cheapest £26/hour & £210/day (Lp Townsend Brickwork) to £47/hour & £306/day (A & M MCGILL BUILDING SERVICE) - average £40/hour & £263/day

Sort by rates or availability

"Two storey extension" - SL6, job posted 26/08/26

"Loft conversion" - SL1, job posted 16/08/26

"Loft conversion" - SLOUGH, job posted 03/07/26

"Outbuilding" - SLOUGH, job posted 28/04/26

"Side return extension" - WINDSOR, job posted 06/03/26

"Remove internal wall , fit RSJ , plaster ceiling" - SL1, job posted 31/01/26

"Garden office" - SL2, job posted 27/08/25

"Outbuilding" - SLOUGH, job posted 27/08/25

"Single storey extension" - SLOUGH, job posted 09/08/25

"Loft conversion" - SLOUGH, job posted 21/06/25

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

"RSJ installation" - SLOUGH, job posted 07/05/25

"Two storey extension" - WINDSOR, job posted 14/04/25

"Loft conversion ( dormer )" - WINDSOR & MAIDENHEAD, job posted 29/03/25

"Rip off - install RSJ beam (3 meter) rear wall, Garage knock, knock dining wall, partially knock sitting wall. It's 1950 semi-detached house and solid walls." - SL3, job posted 25/02/25

"Rip off - one RSJ beam (3 meter) rear wall, brick work for closing 3 door holes, Garage knock, knock dining wall, partially knock sitting wall." - SL3, job posted 24/02/25

"Outbuilding" - SLOUGH, job posted 05/10/24

"Loft conversion" - WINDSOR, job posted 16/09/24

"Side return extension5.9M BY 3 M single floor extention, slant roof, two sky light windows, bi folding doors. knocking down supporting external wall that also joins dining/kitchen to open the whole space up" - WINDSOR & MAIDENHEAD, job posted 29/07/24

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 SL1 extension builders rates

Compare SL1 extension builders rates (excluding VAT or callout charges)
Location in UK	Hourly Rate	Daily Rate
Extension Builders near Slough	£42	£272
Extension Builders near Windsor & Maidenhead	£42	£272
Extension Builders near Windsor	£41	£271
Extension Builders near Maidenhead	£41	£273
Extension Builders near Gerrards Cross	£43	£282
Extension Builders near Egham	£42	£266
Extension Builders near Staines-upon-Thames	£42	£269
Extension Builders near Hillingdon	£63	£276
Extension Builders near Ascot	£41	£276
Extension Builders near Bracknell Forest	£41	£287

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 - £26,128

Garden office - £10,128

Granny annexe - £87,128

Build a flat roof extension - £22,128

Convert a Garage - £16,128

Hip to gable loft conversion - £42,128

Convert a bungalow loft - £29,128

Build a dormer loft conversion - £42,128

Build a swimming pool - £81,128

Build a Mansard loft conversion - £52,128

Concrete foundations - £6,378

Underpin a building - £17,628

Two storey extension - £88,192

Convert a basement - £38,940

Side return extension - £42,940

Loft conversion - £34,950

Garage - £18,628

Single storey extension - £57,560

Outbuilding - £10,128

Install an RSJ - £2,328

Build a kitchen extension - £42,128

More extensions & conversions cost guides...

People in SL1 searching for a Extension Builder also viewed...

Painter and Decorator

The Largest Database of UK Trade Rates

At HaMuch we know what tradespeople charge because we have the largest database of rates anywhere in the UK. If you want quotes for jobs at the right price for you, post your jobs with HaMuch and get your home improvements kickstarted straight away!

Appliance Repair Specialist

Conservatory Specialist