Name: Extension Builder
Brand: HaMuch
SKU: extension-renovation
Rating: 4.63 (4 reviews)

Find affordable NW9 extension builders

Prices range from cheapest £26/hour and £208/day (F C Builders London ltd) to £63/hour and £305/day (EUROCONTRACTOR LIMITED) - average £40/hr and £263/day

HaMuch is Excellent

Local NW9 extension builders & latest jobs

"Dormer loft conversion" - HA8, job posted 06/03/26

"Granny annexe" - COLINDALE, job posted 12/07/25

"Single storey extension" - COLINDALE, job posted 19/02/24

"Loft conversion" - NW9, job posted 18/11/23

Quickly find an Extension Builder in NW9

Use these steps to find Extension Builders in NW9 for FREE!

Post your job: Click "Get quotes" and briefly describe your job.
Enter your details: We’ll match you with Extension Builders in NW9. We’ll notify you via text or email when an Extension Builder is available to quote.
Select your Extension Builder: Compare Extension Builders interested in working with you. You can use HaMuch to safely message local NW9 Extension Builders or phone them directly - you’re in control!

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

Local Extension Builders in London Boroughs

Local Extension Builders in London Boroughs
Borough in London
Extension Builders in Colindale
Extension Builders in Brent Cross
Extension Builders in Edgware
Extension Builders in Mill Hill
Extension Builders in Wembley
Extension Builders in Cricklewood
Extension Builders in Golders Green
Extension Builders in Stanmore
Extension Builders in Wealdstone
Extension Builders in Finchley

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 - £26,136

Garden office - £10,136

Granny annexe - £87,136

Build a flat roof extension - £22,136

Convert a Garage - £16,136

Hip to gable loft conversion - £42,136

Convert a bungalow loft - £29,136

Build a dormer loft conversion - £42,136

Build a swimming pool - £81,136

Build a Mansard loft conversion - £52,136

Concrete foundations - £6,386

Underpin a building - £17,636

Two storey extension - £88,204

Convert a basement - £39,030

Side return extension - £43,030

Loft conversion - £35,025

Garage - £18,636

Single storey extension - £57,720

Outbuilding - £10,136

Install an RSJ - £2,336

Build a kitchen extension - £42,136

More extensions & conversions cost guides...

People in NW9 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