From £17,436
Trusted and professional extension builder in RH12. Experienced in all extension buildering work and keeping within budget and on quote. M + H Buil...
From £17,452
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,916
Established in 2005, GreenBuild provides a sustainable high-end construction service throughout Sussex, Surrey and the surrounding areas. Our exper...
From £17,812
Trusted and professional extension builder in RH12. Experienced in all extension buildering work and keeping within budget and on quote. CadLine Lt...
From £17,484
Trusted and professional extension builder in RH12. Experienced in all extension buildering work and keeping within budget and on quote. Design-a-l...
From £17,556
Capital lofts are a design and build construction company based in Horsham, we provide high quality workmanship from architectural drawings to a f...
From £17,124
Hi I'm an independent patio and drive way specialist with over 10 years experence. My reasonable prices and my professional work is every reason to...
From £17,636
G & R Homes is an established and experienced local extension builder in RH12. Please contact us for a free, no obligation quote and competitive ra...
From £17,636
AWS Home Improvements is an established extension buildering business in RH12. We come highly recommended and provide competitive quotes for your w...
From £17,764
Need an Extension Builder in RH12? Michael & Co has been helping local clients (20 mile radius) with their extension buildering jobs for many years...

Underpinning ranges from £17,124 (Farley Patio & Paving based in RH13) to £17,916 (GreenBuild based in RH13), 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 RH12 by posting a job with HaMuch and we will send it to extension builders in RH12.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Horsham | £32 | £226 |
| Underpin A Building near Crawley | £33 | £227 |
| Underpin A Building near Mid Sussex | £30 | £224 |
| Underpin A Building near Horley | £35 | £234 |
| Underpin A Building near Haywards Heath | £30 | £222 |
| Underpin A Building near Burgess Hill | £31 | £208 |
| Underpin A Building near Reigate | £36 | £238 |
| Underpin A Building near Redhill | £36 | £236 |
| Underpin A Building near Great Bookham | £36 | £235 |
| Underpin A Building near East Grinstead | £32 | £220 |
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 - £17,582

Two storey extension - £88,122

Build a timber frame extension - £26,082

Build a swimming pool - £81,082

Single storey extension - £56,632

Side return extension - £42,418

Install an RSJ - £2,282

Outbuilding - £10,082

Build a Mansard loft conversion - £52,082

Loft conversion - £34,515

Build a kitchen extension - £42,082

Hip to gable loft conversion - £42,082

Granny annexe - £87,082

Garden office - £10,082

Convert a Garage - £16,082

Garage - £18,582

Build a flat roof extension - £22,082

Build a dormer loft conversion - £42,082

Concrete foundations - £6,332

Convert a bungalow loft - £29,082

Convert a basement - £38,418