From £17,596
Need to find an Extension Builder near you for all your extension buildering work?
Pillar Contractors Ltd provides a local, trusted extensi...
From £17,588
Dominic Payte - Design & Build is an established extension buildering business in W1C. We come highly recommended and provide competitive quotes fo...
From £17,900
Starfish Properties is a trusted extension builder serving customers in W1C and the surrounding area. Contact us to today to get a competitive quot...
From £17,580
Experienced extension builder ready to quote for your work. Azur London is the best extension builder in W1C. No obligation free quotes and many ha...
From £17,444
Hestia Contractors Ltd are here to help customers who need an Extension Builder in W1C. We offer a competitive rate to complete all your extension ...
From £17,540
Independent construction company we have wide range of experience, including newconstruction, renovation, design build and retail stores. We provid...
From £17,732
We are specialised in: demolition services, foundation services, property extension, general bricklaying, internal renovation and configuration, ca...
From £17,972
We are a Design and Build Company, based in London.We focus on super prime and luxury residential renovations in and around London and internationa...
From £17,540
We Love Build - Three Arches is an established extension buildering business in W1C. We come highly recommended and provide competitive quotes for ...
From £17,484
JK Doors is a trusted extension builder serving customers in W1C and the surrounding area. Contact us to today to get a competitive quote for exten...

Underpinning ranges from £17,444 (Hestia Contractors Ltd based in W1B) to £17,972 (We Love Build based in W1J), 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 W1C by posting a job with HaMuch and we will send it to extension builders in W1C.
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 - £17,638

Two storey extension - £88,206

Build a timber frame extension - £26,138

Build a swimming pool - £81,138

Single storey extension - £57,752

Side return extension - £43,048

Install an RSJ - £2,338

Outbuilding - £10,138

Build a Mansard loft conversion - £52,138

Loft conversion - £35,040

Build a kitchen extension - £42,138

Hip to gable loft conversion - £42,138

Granny annexe - £87,138

Garden office - £10,138

Convert a Garage - £16,138

Garage - £18,638

Build a flat roof extension - £22,138

Build a dormer loft conversion - £42,138

Concrete foundations - £6,388

Convert a bungalow loft - £29,138

Convert a basement - £39,048