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

Find affordable CM20 extension builders

Prices range from cheapest £36/hour and £230/day (THE ROMAN BUILDING COMPANY) to £81/hour and £644/day (Essex loft extensions Ltd ) - average £45/hr and £291/day

HaMuch is Excellent

Local CM20 extension builders & latest jobs

"Loft conversion" - HARLOW, job posted 27/05/26

"Kitchen extension" - HARLOW, job posted 30/12/25

"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" - CM18, job posted 28/07/25

"Single storey extension" - HARLOW, job posted 17/02/25

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 CM20 extension builders rates

Compare CM20 extension builders rates (excluding VAT or callout charges)
Location in UK	Hourly Rate	Daily Rate
Extension Builders near Harlow	£43	£288
Extension Builders near Hoddesdon	£46	£296
Extension Builders near Ware	£47	£296
Extension Builders near Bishop's Stortford	£42	£264
Extension Builders near Cheshunt	£48	£285
Extension Builders near Epping Forest	£44	£273
Extension Builders near Hertford	£46	£289
Extension Builders near Loughton	£44	£273
Extension Builders near East Hertfordshire	£44	£289
Extension Builders near Welwyn Garden City	£42	£268

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 - £26,328

Garden office - £10,328

Granny annexe - £87,328

Build a flat roof extension - £22,328

Convert a Garage - £16,328

Hip to gable loft conversion - £42,328

Convert a bungalow loft - £29,328

Build a dormer loft conversion - £42,328

Build a swimming pool - £81,328

Build a Mansard loft conversion - £52,328

Concrete foundations - £6,578

Underpin a building - £17,828

Two storey extension - £88,492

Convert a basement - £41,190

Side return extension - £45,190

Loft conversion - £36,825

Garage - £18,828

Single storey extension - £61,560

Outbuilding - £10,328

Install an RSJ - £2,528

Build a kitchen extension - £42,328

More extensions & conversions cost guides...

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