From £17,820
London, E1
Need to find an Extension Builder near you for all your extension buildering work?
Renobuild Group provides a local, trusted extension buil...
From £17,668
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,780
Greater London, E1
Need to find an Extension Builder near you for all your extension buildering work?
Jamie Brown Construction provides a local, trusted exten...
From £17,892
Our company is based in the South East of England, covering Kent, Essex, London and the surrounding areas. We have over 25 years of experience deal...
From £18,004
Greater London, E1
PMG Design & Build Ltd is an established and experienced local extension builder in E1. Please contact us for a free, no obligation quote and compe...
From £17,836
Pencil and Brick is the collective name for our architect practice and our construction company. We're based in East London.We work on a wide range...
From £17,428
Shoreditch, E1
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,716
Trusted and professional extension builder in E1. Experienced in all extension buildering work and keeping within budget and on quote. AB Building ...
From £17,580
Checa Romero is an established and experienced local extension builder in E1. Please contact us for a free, no obligation quote and competitive rat...
From £18,028
Gabriel Shin is an established and experienced local extension builder in E1. Please contact us for a free, no obligation quote and competitive rat...

Underpinning ranges from £17,428 (Builders based in E1) to £18,028 (Gabriel Shin based in E1), 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 E1 by posting a job with HaMuch and we will send it to extension builders in E1.
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 - £17,775

Two storey extension - £88,413

Build a timber frame extension - £26,275

Build a swimming pool - £81,275

Single storey extension - £60,504

Side return extension - £44,596

Install an RSJ - £2,475

Outbuilding - £10,275

Build a Mansard loft conversion - £52,275

Loft conversion - £36,330

Build a kitchen extension - £42,275

Hip to gable loft conversion - £42,275

Granny annexe - £87,275

Garden office - £10,275

Convert a Garage - £16,275

Garage - £18,775

Build a flat roof extension - £22,275

Build a dormer loft conversion - £42,275

Concrete foundations - £6,525

Convert a bungalow loft - £29,275

Convert a basement - £40,596