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 £19,084
Propello is an established and experienced local extension builder in Knebworth. Please contact us for a free, no obligation quote and competitive...
From £17,924
Sharp Building Ltd is an established and experienced local extension builder in Knebworth. Please contact us for a free, no obligation quote and co...
From £17,420
NISUP BUILDING SERVICES Company specializes in the domestic and commercial building industry :1. Refurbishm...
From £17,732
If you are looking for a Knebworth extension builder and you need something replaced, fitted, or fixed, contact Space Above Limited today. We are c...
From £17,924
Nouvell Decor is a trusted extension builder serving customers in Knebworth and the surrounding area. Contact us to today to get a competitive quot...
From £17,932
Platinum Electrics is a Branch off Platinum Premier Projects who deal in all types of construction projects. Platinum Electrics are based in London...
From £17,612
JJSR Construction Ltd is an established and experienced local extension builder in Knebworth. Please contact us for a free, no obligation quote and...
From £17,500
Member since July 2020
EB Construction & Building Ltd are here to help customers who need an Extension Builder in Knebworth. We offer a competitive rate to complete all y...
From £17,844
Trusted and professional extension builder in Knebworth. Experienced in all extension buildering work and keeping within budget and on quote. Peter...

Underpinning ranges from £17,420 (Nisup Building Services based in HA8) to £19,084 (Propello based in E17), 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 Knebworth by posting a job with HaMuch and we will send it to extension builders in Knebworth.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Stevenage | £44 | £282 |
| Underpin A Building near Welwyn Garden City | £42 | £268 |
| Underpin A Building near Hertford | £46 | £289 |
| Underpin A Building near Hitchin | £43 | £283 |
| Underpin A Building near East Hertfordshire | £44 | £289 |
| Underpin A Building near North Hertfordshire | £44 | £283 |
| Underpin A Building near Hatfield | £64 | £283 |
| Underpin A Building near Ware | £47 | £296 |
| Underpin A Building near Harpenden | £86 | £315 |
| Underpin A Building near Letchworth | £44 | £283 |
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 - £17,903

Two storey extension - £88,605

Build a timber frame extension - £26,403

Build a swimming pool - £81,403

Single storey extension - £63,064

Side return extension - £46,036

Install an RSJ - £2,603

Outbuilding - £10,403

Build a Mansard loft conversion - £52,403

Loft conversion - £37,530

Build a kitchen extension - £42,403

Hip to gable loft conversion - £42,403

Granny annexe - £87,403

Garden office - £10,403

Convert a Garage - £16,403

Garage - £18,903

Build a flat roof extension - £22,403

Build a dormer loft conversion - £42,403

Concrete foundations - £6,653

Convert a bungalow loft - £29,403

Convert a basement - £42,036