In an unstable market house extensions are often the most viable option, helping you to get the most out of the space you have without the addition...
Gary Braine
Experienced extension builder ready to quote for your work. G B BUILDSTORE LTD is the best extension builder in SG1. No obligation free quotes and ...
From £18,004
WALKERN CONSTRUCTION LIMITED is an established and experienced local extension builder in SG1. Please contact us for a free, no obligation quote an...
From £17,772
Harris Building Solutions Limited is an established extension buildering business in SG1. We come highly recommended and provide competitive quotes...
From £17,732
We are a local roofing company offering a complete roofing service.We provide one of the most cost effective, reliable roofing services in and ...
From £17,820
Totalworth Building Services is an established extension buildering business in SG1. We come highly recommended and provide competitive quotes for ...
From £17,660
Andy N
Experienced extension builder ready to quote for your work. Precision Roofing & Building Maintenance is the best extension builder in SG1. No oblig...
From £17,860
We are a family run business with over 30 years of combined experience, we offer everything from replacing doors and worktops on your kitchen to sm...
From £17,668
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,596
Relax... you have found a reliable extension builder in SG1. GB Build is a friendly and reliable company based in SG1 who consider no job as too bi...

Underpinning ranges from £17,516 (G B BUILDSTORE LTD based in SG1) to £18,004 (WALKERN CONSTRUCTION LIMITED based in SG2), 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 SG1 by posting a job with HaMuch and we will send it to extension builders in SG1.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Stevenage | £44 | £282 |
| Underpin A Building near Hitchin | £43 | £283 |
| Underpin A Building near North Hertfordshire | £44 | £283 |
| Underpin A Building near Letchworth | £44 | £283 |
| Underpin A Building near East Hertfordshire | £44 | £289 |
| Underpin A Building near Welwyn Garden City | £42 | £269 |
| Underpin A Building near Hertford | £46 | £290 |
| Underpin A Building near Harpenden | £87 | £317 |
| Underpin A Building near Luton | £42 | £279 |
| Underpin A Building near Ware | £47 | £296 |
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 - £17,732

Two storey extension - £88,348

Build a timber frame extension - £26,232

Build a swimming pool - £81,232

Single storey extension - £59,640

Side return extension - £44,110

Install an RSJ - £2,432

Outbuilding - £10,232

Build a Mansard loft conversion - £52,232

Loft conversion - £35,925

Build a kitchen extension - £42,232

Hip to gable loft conversion - £42,232

Granny annexe - £87,232

Garden office - £10,232

Convert a Garage - £16,232

Garage - £18,732

Build a flat roof extension - £22,232

Build a dormer loft conversion - £42,232

Concrete foundations - £6,482

Convert a bungalow loft - £29,232

Convert a basement - £40,110