From £17,604
London, W4
Starling Constructions Ltd is an established and experienced local extension builder in W4. Please contact us for a free, no obligation quote and c...
From £17,988
Greater London, W4
Kuta Design and Build Limited is an established and experienced local extension builder in W4. Please contact us for a free, no obligation quote an...
From £17,804
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,524
Greater London, W4
Relax... you have found a reliable extension builder in W4. Elite London Construction is a friendly and reliable company based in W4 who consider n...
From £17,652
Good Design and Build are here to help customers who need an Extension Builder in W4. We offer a competitive rate to complete all your extension bu...
From £17,716
Londonderry, W4
Guardian Developments is a west London based design and build company, specialising in residential projects including extensions, refurbishments a...
From £17,580
Relax... you have found a reliable extension builder in W4. Zulufish is a friendly and reliable company based in W4 who consider no job as too big ...
From £17,836
Midlothian, W4
Smart Property Sourcing is a trusted extension builder serving customers in W4 and the surrounding area. Contact us to today to get a competitive q...
From £17,564
Pipedreams Interiors Ltd are here to help customers who need an Extension Builder in W4. We offer a competitive rate to complete all your extension...

Underpinning ranges from £17,500 (SxS Design & Build based in W4) to £17,988 (Kuta Design and Build Limited based in W4), but the final cost will depend on the method of underpinning used, how much of your foundations need underpinning and where you live.
Comparing extension builders estimates for underpinning gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
Get quotes to underpin your home in W4 by posting a job with HaMuch and we will send it to extension builders in W4.
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.

Underpin a building - £17,677

Two storey extension - £88,265

Build a timber frame extension - £26,177

Build a swimming pool - £81,177

Single storey extension - £58,536

Side return extension - £43,489

Install an RSJ - £2,377

Outbuilding - £10,177

Build a Mansard loft conversion - £52,177

Loft conversion - £35,408

Build a kitchen extension - £42,177

Hip to gable loft conversion - £42,177

Granny annexe - £87,177

Garden office - £10,177

Convert a Garage - £16,177

Garage - £18,677

Build a flat roof extension - £22,177

Build a dormer loft conversion - £42,177

Concrete foundations - £6,427

Convert a bungalow loft - £29,177

Convert a basement - £39,489