From £17,636
Experienced extension builder ready to quote for your work. Building & Renovation Services Zdzislaw Zalewski is the best extension builder in HP3. ...
From £17,652
JH Refurbishments are here to help customers who need an Extension Builder in HP3. We offer a competitive rate to complete all your extension build...
From £17,636
Experienced extension builder ready to quote for your work. SWAT Design and Build Ltd is the best extension builder in HP3. No obligation free quot...
From £17,580
BOXMOOR BLDG & CARP SERVICES is a trusted extension builder serving customers in HP3 and the surrounding area. Contact us to today to get a competi...
From £17,860
Need an Extension Builder in HP3? MW The Building Specialists Ltd has been helping local clients (20 mile radius) with their extension buildering j...
From £17,580
WHITE HART BUILDING LIMITED is a trusted extension builder serving customers in HP3 and the surrounding area. Contact us to today to get a competit...
From £17,980
R Gabriel Carpentry & Builders is a trusted extension builder serving customers in HP3 and the surrounding area. Contact us to today to get a compe...
From £17,612
Need to find an Extension Builder near you for all your extension buildering work?
AUBREY BUILDING SERVICES LTD provides a local, trusted e...
From £17,444
Relax... you have found a reliable extension builder in HP3. Ellis Construction is a friendly and reliable company based in HP3 who consider no job...
From £17,748
Relax... you have found a reliable extension builder in HP3. R KENT BUILDERS is a friendly and reliable company based in HP3 who consider no job as...

Underpinning ranges from £17,444 (Ellis Construction based in HP1) to £17,980 (R Gabriel Carpentry & Builders based in HP2), 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 HP3 by posting a job with HaMuch and we will send it to extension builders in HP3.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Dacorum | £42 | £269 |
| Underpin A Building near Hemel Hempstead | £42 | £270 |
| Underpin A Building near Berkhamsted | £41 | £263 |
| Underpin A Building near St Albans | £63 | £288 |
| Underpin A Building near Chesham | £42 | £277 |
| Underpin A Building near Rickmansworth | £42 | £278 |
| Underpin A Building near Watford | £43 | £278 |
| Underpin A Building near Harpenden | £86 | £315 |
| Underpin A Building near Bushey | £42 | £276 |
| Underpin A Building near Borehamwood | £42 | £270 |
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 - £17,673

Two storey extension - £88,259

Build a timber frame extension - £26,173

Build a swimming pool - £81,173

Single storey extension - £58,456

Side return extension - £43,444

Install an RSJ - £2,373

Outbuilding - £10,173

Build a Mansard loft conversion - £52,173

Loft conversion - £35,370

Build a kitchen extension - £42,173

Hip to gable loft conversion - £42,173

Granny annexe - £87,173

Garden office - £10,173

Convert a Garage - £16,173

Garage - £18,673

Build a flat roof extension - £22,173

Build a dormer loft conversion - £42,173

Concrete foundations - £6,423

Convert a bungalow loft - £29,173

Convert a basement - £39,444