Name: Extension Builder
Brand: HaMuch
SKU: extension-renovation
Rating: 4.5 (4 reviews)

Find affordable Sidcup extension builders

Prices range from cheapest £25/hour and £233/day (GW Building Solutions) to £55/hour and £327/day (HOUSE BUILDING SERVICES LIMITED) - average £42/hr and £264/day

HaMuch is Excellent

Local Sidcup extension builders & latest jobs

"Outbuilding" - SIDCUP, job posted 12/11/25

"House clearing - same property you have serviced before" - DA5, job posted 11/10/25

"Single storey extension" - DA15, job posted 20/05/25

"Underpinning" - BEXLEY, job posted 10/03/25

Quickly find an Extension Builder in Sidcup

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

Post your job: Click "Get quotes" and briefly describe your job.
Enter your details: We’ll match you with Extension Builders in Sidcup. 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 Sidcup 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 Sidcup
Extension Builders in Bexley
Extension Builders in Bexley
Extension Builders in Chislehurst
Extension Builders in Bexleyheath
Extension Builders in Petts Wood
Extension Builders in Welling
Extension Builders in Eltham
Extension Builders in Barnehurst
Extension Builders in Swanley

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 - £26,072

Garden office - £10,072

Granny annexe - £87,072

Build a flat roof extension - £22,072

Convert a Garage - £16,072

Hip to gable loft conversion - £42,072

Convert a bungalow loft - £29,072

Build a dormer loft conversion - £42,072

Build a swimming pool - £81,072

Build a Mansard loft conversion - £52,072

Concrete foundations - £6,322

Underpin a building - £17,572

Two storey extension - £88,108

Convert a basement - £38,310

Side return extension - £42,310

Loft conversion - £34,425

Garage - £18,572

Single storey extension - £56,440

Outbuilding - £10,072

Install an RSJ - £2,272

Build a kitchen extension - £42,072

More extensions & conversions cost guides...

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