Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in Merton. No obligation free quot...
Robert Buci
Buci builders ltd is a trusted extension builder serving customers in Merton and the surrounding area. Contact us to today to get a competitive quo...
Tenfold Renovation
Need to find an Extension Builder near you for all your extension buildering work?
Tenfold Renovation provides a local, trusted extension b...
Sebastian Banga
Banga decoration. Is Base in south London for number of year Banga decoration is a small company. Wich provide an excellent job to the custom...
Trusted and professional extension builder in Merton. Experienced in all extension buildering work and keeping within budget and on quote. CSJ Buil...
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
PW Construction & Renovation Ltd is a trusted extension builder serving customers in Merton and the surrounding area. Contact us to today to get a ...
John Mcdonagh
Watch our short video highlighting all our expertise and services here:
more than 10 y...
Trusted and professional extension builder in Merton. Experienced in all extension buildering work and keeping within budget and on quote. Sonik Bu...

Underpinning ranges from £17,436 (Masters Property Services based in SM5) to £18,700 (Banga Decoration based in CR7), 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 Merton by posting a job with HaMuch and we will send it to extension builders in Merton.
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 - £17,833

Two storey extension - £88,499

Build a timber frame extension - £26,333

Build a swimming pool - £81,333

Single storey extension - £61,656

Side return extension - £45,244

Install an RSJ - £2,533

Outbuilding - £10,333

Build a Mansard loft conversion - £52,333

Loft conversion - £36,870

Build a kitchen extension - £42,333

Hip to gable loft conversion - £42,333

Granny annexe - £87,333

Garden office - £10,333

Convert a Garage - £16,333

Garage - £18,833

Build a flat roof extension - £22,333

Build a dormer loft conversion - £42,333

Concrete foundations - £6,583

Convert a bungalow loft - £29,333

Convert a basement - £41,244