From £18,068
Experienced extension builder ready to quote for your work. Ashtons is the best extension builder in Harpenden. No obligation free quotes and many ...
From £17,812
Trusted and professional extension builder in Harpenden. Experienced in all extension buildering work and keeping within budget and on quote. Home ...
From £17,844
Harpenden, AL5
Trusted and professional extension builder in Harpenden. Experienced in all extension buildering work and keeping within budget and on quote. Peter...
From £17,772
Harpenden, AL5
Experienced extension builder ready to quote for your work. Priolotiling is the best extension builder in Harpenden. No obligation free quotes and ...
From £17,612
4siblings are here to help customers who need an Extension Builder in Harpenden. We offer a competitive rate to complete all your extension builder...
From £17,564
We pride ourselves in offering transparent, collaborative construction services, defining your project, through planning and taking your project t...
From £17,900
Bob's Home Maintenance are here to help customers who need an Extension Builder in Harpenden. We offer a competitive rate to complete all your exte...
From £17,524
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...
From £18,028
Billy Homan set up Grain Property to provide high-quality design, seamless project delivery, and a commitment to excellent communication throughout...
From £17,484
Abalon is Western Canada’s leading foundation repair and basement waterproofing company, operating in the Edmonton area for over 40 years (50 yea...

Underpinning ranges from £17,484 (Abalon Construction based in ZZ99) to £18,068 (Ashtons based in Al5), 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 Harpenden by posting a job with HaMuch and we will send it to extension builders in Harpenden.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Harpenden | £86 | £315 |
| Underpin A Building near St Albans | £63 | £288 |
| Underpin A Building near Luton | £42 | £276 |
| Underpin A Building near Hatfield | £64 | £283 |
| Underpin A Building near Hemel Hempstead | £42 | £270 |
| Underpin A Building near Welwyn Garden City | £42 | £268 |
| Underpin A Building near Dacorum | £42 | £269 |
| Underpin A Building near Hitchin | £43 | £283 |
| Underpin A Building near Dunstable | £41 | £270 |
| Underpin A Building near Stevenage | £44 | £282 |
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 - £17,761

Two storey extension - £88,391

Build a timber frame extension - £26,261

Build a swimming pool - £81,261

Single storey extension - £60,216

Side return extension - £44,434

Install an RSJ - £2,461

Outbuilding - £10,261

Build a Mansard loft conversion - £52,261

Loft conversion - £36,195

Build a kitchen extension - £42,261

Hip to gable loft conversion - £42,261

Granny annexe - £87,261

Garden office - £10,261

Convert a Garage - £16,261

Garage - £18,761

Build a flat roof extension - £22,261

Build a dormer loft conversion - £42,261

Concrete foundations - £6,511

Convert a bungalow loft - £29,261

Convert a basement - £40,434