From £17,548
Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in GU21. No obligation free quotes...
From £17,836
Aerea is a trusted extension builder serving customers in GU21 and the surrounding area. Contact us to today to get a competitive quote for extensi...
From £17,780
Member since August 2026
Relax... you have found a reliable extension builder in GU21. ABC Associates STRUCTURES 4 U is a friendly and reliable company based in GU21 who co...
From £17,692
Need an Extension Builder in GU21? VA Structures has been helping local clients (10 mile radius) with their extension buildering jobs for many year...
From £17,780
Trusted and professional extension builder in GU21. Experienced in all extension buildering work and keeping within budget and on quote. DC Build &...
From £17,812
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,932
DP Services is a fully insured friendly local company which has been trading since 2002 and delivers high quality building work in domestic extensi...
From £17,804
Hi we have 15 years of experience in building and construction industry our specialization is bathrooms and renovations please have a look at the w...
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 £17,404
Elite Construction London Ltd has been one of the top providers of building and remodeling services in London for more than ten years.Our goal is ...

Underpinning ranges from £17,404 (Elite Construction London Ltd based in TW8) to £17,932 (DP Services based in RG41), 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 GU21 by posting a job with HaMuch and we will send it to extension builders in GU21.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Woking | £43 | £277 |
| Underpin A Building near New Haw | £43 | £273 |
| Underpin A Building near Guildford | £53 | £298 |
| Underpin A Building near Ascot | £41 | £276 |
| Underpin A Building near Camberley | £41 | £283 |
| Underpin A Building near Ash Vale | £41 | £277 |
| Underpin A Building near Egham | £42 | £266 |
| Underpin A Building near Farnborough | £41 | £273 |
| Underpin A Building near Staines-upon-Thames | £42 | £269 |
| Underpin A Building near Walton-on-Thames | £43 | £277 |
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 - £17,751

Two storey extension - £88,377

Build a timber frame extension - £26,251

Build a swimming pool - £81,251

Single storey extension - £60,024

Side return extension - £44,326

Install an RSJ - £2,451

Outbuilding - £10,251

Build a Mansard loft conversion - £52,251

Loft conversion - £36,105

Build a kitchen extension - £42,251

Hip to gable loft conversion - £42,251

Granny annexe - £87,251

Garden office - £10,251

Convert a Garage - £16,251

Garage - £18,751

Build a flat roof extension - £22,251

Build a dormer loft conversion - £42,251

Concrete foundations - £6,501

Convert a bungalow loft - £29,251

Convert a basement - £40,326