From £17,548
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in HA9. No obligation free quotes ...
From £17,612
Trusted and professional extension builder in HA9. Experienced in all extension buildering work and keeping within budget and on quote. D Dan Const...
From £17,924
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,644
ABC Building & Maintenance Contractors Ltd is a trusted extension builder serving customers in HA9 and the surrounding area. Contact us to today to...
From £17,684
Experienced extension builder ready to quote for your work. DIAL 1ST CONSTRUCTION LTD is the best extension builder in HA9. No obligation free quot...
From £17,660
Trusted and professional extension builder in HA9. Experienced in all extension buildering work and keeping within budget and on quote. PARKWAY MAI...
From £17,932
London, HA9
Krystian Wojasiewicz is a trusted extension builder serving customers in HA9 and the surrounding area. Contact us to today to get a competitive quo...
From £17,748
C & A Contractors is a trusted extension builder serving customers in HA9 and the surrounding area. Contact us to today to get a competitive quote ...
From £17,484
Need an Extension Builder in HA9? DIU Builders Group UK has been helping local clients (10 mile radius) with their extension buildering jobs for ma...
From £17,812
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...

Underpinning ranges from £17,484 (DIU Builders Group UK based in HA0) to £17,932 (Krystian Wojasiewicz based in HA9), 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 HA9 by posting a job with HaMuch and we will send it to extension builders in HA9.
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 - £17,705

Two storey extension - £88,307

Build a timber frame extension - £26,205

Build a swimming pool - £81,205

Single storey extension - £59,096

Side return extension - £43,804

Install an RSJ - £2,405

Outbuilding - £10,205

Build a Mansard loft conversion - £52,205

Loft conversion - £35,670

Build a kitchen extension - £42,205

Hip to gable loft conversion - £42,205

Granny annexe - £87,205

Garden office - £10,205

Convert a Garage - £16,205

Garage - £18,705

Build a flat roof extension - £22,205

Build a dormer loft conversion - £42,205

Concrete foundations - £6,455

Convert a bungalow loft - £29,205

Convert a basement - £39,804