Name: Extension Builder
Brand: HaMuch
SKU: extension-renovation
Rating: 4.55 (11 reviews)

Find affordable SO50 extension builders

Cheapest £20/hour & £153/day (ANDYWORKS & son Ltd) to £38/hour & £330/day (CSY Construction Ltd) - average £33/hour & £243/day

Local SO50 extension builders with reviews/jobs - Sort by rates or availability

"Dormer loft conversion" - EASTLEIGH, job posted 11/04/26

"Two storey and side extension" - SO16, job posted 26/01/26

"Underpinning" - SOUTHAMPTON, job posted 18/10/25

"Build a dormer loft conversion" - SO17, job posted 10/08/25

"Cost of a loft conversion" - SO17, job posted 10/08/25

"Two storey extension 3.6 x 8 x2" - SOUTHAMPTON, job posted 20/06/25

"Garden office" - SOUTHAMPT, job posted 21/01/25

"Kitchen extension" - SOUTHAMPTON, job posted 19/10/24

"Single storey extension" - SO15, job posted 09/03/24

"Side return extension" - EASTLEIGH, job posted 18/11/23

"Single storey extension" - SOUTHAMPTON, job posted 17/10/23

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 SO50 extension builders rates

Compare SO50 extension builders rates (excluding VAT or callout charges)
Location in UK	Hourly Rate	Daily Rate
Extension Builders near Eastleigh	£34	£244
Extension Builders near Chandler's Ford	£34	£245
Extension Builders near Hedge End	£34	£244
Extension Builders near Southampton	£34	£243
Extension Builders near Winchester	£37	£266
Extension Builders near Locks Heath	£33	£240
Extension Builders near Romsey	£32	£230
Extension Builders near Totton	£34	£243
Extension Builders near Fareham	£35	£250
Extension Builders near Lee-on-the-Solent	£35	£249

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 - £25,944

Garden office - £9,944

Granny annexe - £86,944

Build a flat roof extension - £21,944

Convert a Garage - £15,944

Hip to gable loft conversion - £41,944

Convert a bungalow loft - £28,944

Build a dormer loft conversion - £41,944

Build a swimming pool - £80,944

Build a Mansard loft conversion - £51,944

Concrete foundations - £6,194

Underpin a building - £17,444

Two storey extension - £87,916

Convert a basement - £36,870

Side return extension - £40,870

Loft conversion - £33,225

Garage - £18,444

Single storey extension - £53,880

Outbuilding - £9,944

Install an RSJ - £2,144

Build a kitchen extension - £41,944

More extensions & conversions cost guides...

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