From £17,548
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in Fleet Street. No obligation fre...
From £18,060
Our homes need to be regularly maintained and from time to time they need to be rejuvenated, modernised and enhanced. When it comes to building wor...
From £17,596
Experienced extension builder ready to quote for your work. Mr is the best extension builder in Fleet Street. No obligation free quotes and many ha...
From £17,484
JK Doors is a trusted extension builder serving customers in Fleet Street and the surrounding area. Contact us to today to get a competitive quote ...
From £17,692
NIECEIC / NAAPIT GASSAFE WATER REGULATIONS We offer services towards completion of high end construction projects to dis...
From £17,892
Need an Extension Builder in Fleet Street? Samuele Paolini has been helping local clients (5 mile radius) with their extension buildering jobs for...
From £17,812
skilled worker who specializes in completing a wide range of building and renovation projects
From £18,116
HOUSE BUILDING SERVICES LIMITED is a trusted extension builder serving customers in Fleet Street and the surrounding area. Contact us to today to g...
From £17,388
Member since April 2025
Trusted and professional extension builder in Fleet Street. Experienced in all extension buildering work and keeping within budget and on quote. GR...
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 £17,388 (GR MAINTENANCE LTD based in IG11) to £18,116 (HOUSE BUILDING SERVICES LIMITED based in DA16), 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 Fleet Street by posting a job with HaMuch and we will send it to extension builders in Fleet Street.
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 - £17,740

Two storey extension - £88,360

Build a timber frame extension - £26,240

Build a swimming pool - £81,240

Single storey extension - £59,800

Side return extension - £44,200

Install an RSJ - £2,440

Outbuilding - £10,240

Build a Mansard loft conversion - £52,240

Loft conversion - £36,000

Build a kitchen extension - £42,240

Hip to gable loft conversion - £42,240

Granny annexe - £87,240

Garden office - £10,240

Convert a Garage - £16,240

Garage - £18,740

Build a flat roof extension - £22,240

Build a dormer loft conversion - £42,240

Concrete foundations - £6,490

Convert a bungalow loft - £29,240

Convert a basement - £40,200