From £17,908
London, N1
Our building services company Upper Class Builders based in London and the surrounding area, providing professional, trustworthy building services....
From £17,404
Regent Developments is an established and experienced local extension builder in N1. Please contact us for a free, no obligation quote and competit...
From £17,708
London, N1
Need to find an Extension Builder near you for all your extension buildering work?
Build Place Ltd provides a local, trusted extension buil...
From £17,580
At PRG Extensions we a collective of skilled professionals who have the client in the forefront of their minds when we 'plan' 'design' & 'build' ou...
From £17,812
Surrey, N1
Ant-works is an established extension buildering business in N1. We come highly recommended and provide competitive quotes for your work.
From £17,900
Need an Extension Builder in N1? Juxtacon Ltd has been helping local clients (5 mile radius) with their extension buildering jobs for many years. G...
From £17,364
Greater London, N1
Trusted and professional extension builder in N1. Experienced in all extension buildering work and keeping within budget and on quote. PRG Extensio...
From £17,716
Experienced extension builder ready to quote for your work. Sandhill Bulding Solutions Ltd is the best extension builder in N1. No obligation free ...
From £17,988
Greater London, N1
Carta Nova is a studio for architecture and interior design based in London.We believe that good design makes your life easier, and it is fun — w...
From £17,916
CMT Ltd is an established extension buildering business in N1. We come highly recommended and provide competitive quotes for your work.

Underpinning ranges from £17,364 (PRG Extensions based in N1) to £17,988 (CARTA NOVA - Architecture & Beyond based in N1), 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 N1 by posting a job with HaMuch and we will send it to extension builders in N1.
"Underpin a building" - N7, job posted 01/01/70
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 - £17,730

Two storey extension - £88,344

Build a timber frame extension - £26,230

Build a swimming pool - £81,230

Single storey extension - £59,592

Side return extension - £44,083

Install an RSJ - £2,430

Outbuilding - £10,230

Build a Mansard loft conversion - £52,230

Loft conversion - £35,903

Build a kitchen extension - £42,230

Hip to gable loft conversion - £42,230

Granny annexe - £87,230

Garden office - £10,230

Convert a Garage - £16,230

Garage - £18,730

Build a flat roof extension - £22,230

Build a dormer loft conversion - £42,230

Concrete foundations - £6,480

Convert a bungalow loft - £29,230

Convert a basement - £40,083