From £17,612
MamCon is a trusted extension builder serving customers in West Sussex and the surrounding area. Contact us to today to get a competitive quote for...
From £17,652
Alexander Kitchens are here to help customers who need an Extension Builder in West Sussex. We offer a competitive rate to complete all your extens...
From £17,660
Need to find an Extension Builder near you for all your extension buildering work?
Boss Building Contractors Ltd provides a local, trusted ...
From £17,300
Trusted and professional extension builder in West Sussex. Experienced in all extension buildering work and keeping within budget and on quote. Nut...
From £17,612
Our building services company Pearl Building Ltd with over 25 years experience in the trade. During this time we have been helping customers in Lan...
From £17,492
Member since August 2026
H P Building Services Sussex is a one-stop solution for all your extension buildering needs. Establish over 10 years ago and covering 20 miles arou...
From £17,436
ACF Carpentry Ltd is an established and experienced local extension builder in West Sussex. Please contact us for a free, no obligation quote and c...
From £17,620
Experienced extension builder ready to quote for your work. SOUTHWAYS CONSTRUCTION is the best extension builder in West Sussex. No obligation free...
From £17,940
Need to find an Extension Builder near you for all your extension buildering work?
Main Construction provides a local, trusted extension bu...
From £17,484
A new extension provides many different solutions to age old problems. The list of how an extension can transform your property is long and varied....

Underpinning ranges from £17,300 (Nutshell Construction based in BN14) to £17,940 (Main Construction based in BN12), 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 West Sussex by posting a job with HaMuch and we will send it to extension builders in West Sussex.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Worthing | £35 | £251 |
| Underpin A Building near Lancing | £37 | £251 |
| Underpin A Building near Shoreham-by-Sea | £36 | £250 |
| Underpin A Building near Rustington | £36 | £246 |
| Underpin A Building near Littlehampton | £35 | £244 |
| Underpin A Building near Arun | £35 | £241 |
| Underpin A Building near Brighton | £35 | £251 |
| Underpin A Building near Brighton and Hove | £35 | £251 |
| Underpin A Building near Bognor Regis | £35 | £247 |
| Underpin A Building near Burgess Hill | £36 | £240 |
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 - £17,581

Two storey extension - £88,121

Build a timber frame extension - £26,081

Build a swimming pool - £81,081

Single storey extension - £56,616

Side return extension - £42,409

Install an RSJ - £2,281

Outbuilding - £10,081

Build a Mansard loft conversion - £52,081

Loft conversion - £34,508

Build a kitchen extension - £42,081

Hip to gable loft conversion - £42,081

Granny annexe - £87,081

Garden office - £10,081

Convert a Garage - £16,081

Garage - £18,581

Build a flat roof extension - £22,081

Build a dormer loft conversion - £42,081

Concrete foundations - £6,331

Convert a bungalow loft - £29,081

Convert a basement - £38,409