From £17,300
Need to find an Extension Builder near you for all your extension buildering work?
DC Roofing & Sons Ltd provides a local, trusted extensio...
From £17,324
Relax... you have found a reliable extension builder in PO3. Bribern Property Services is a friendly and reliable company based in PO3 who consider...
From £17,468
Experienced extension builder ready to quote for your work. Shepperd Developments is the best extension builder in PO3. No obligation free quotes a...
From £17,284
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,588
Experienced extension builder ready to quote for your work. JM Roofing & Building Services is the best extension builder in PO3. No obligation free...
From £17,500
Build Light Group is an established and experienced local extension builder in PO3. Please contact us for a free, no obligation quote and competiti...
From £17,212
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,484
Sigma Probuild Ltd is an established extension buildering business in PO3. We come highly recommended and provide competitive quotes for your work....
From £17,444
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £17,500
Experienced extension builder ready to quote for your work. Pompey Homes Ltd is the best extension builder in PO3. No obligation free quotes and ma...

Underpinning ranges from £17,212 (Westcott Construction Ltd based in PO3) to £17,588 (JM Roofing & Building Services based in PO2), 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 PO3 by posting a job with HaMuch and we will send it to extension builders in PO3.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Portsmouth | £36 | £250 |
| Underpin A Building near Gosport | £35 | £246 |
| Underpin A Building near Havant & Waterloo | £35 | £248 |
| Underpin A Building near Havant | £35 | £249 |
| Underpin A Building near Waterlooville | £36 | £250 |
| Underpin A Building near Fareham | £35 | £250 |
| Underpin A Building near Lee-on-the-Solent | £35 | £249 |
| Underpin A Building near Horndean | £35 | £253 |
| Underpin A Building near Locks Heath | £33 | £240 |
| Underpin A Building near Chichester | £34 | £242 |
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 - £17,410

Two storey extension - £87,866

Build a timber frame extension - £25,910

Build a swimming pool - £80,910

Single storey extension - £53,208

Side return extension - £40,492

Install an RSJ - £2,110

Outbuilding - £9,910

Build a Mansard loft conversion - £51,910

Loft conversion - £32,910

Build a kitchen extension - £41,910

Hip to gable loft conversion - £41,910

Granny annexe - £86,910

Garden office - £9,910

Convert a Garage - £15,910

Garage - £18,410

Build a flat roof extension - £21,910

Build a dormer loft conversion - £41,910

Concrete foundations - £6,160

Convert a bungalow loft - £28,910

Convert a basement - £36,492