From £11,096
We are a Small Family run business with over 30 years experience in the building trade, Carpentry is my main trade, with NVQ Level 2.
From £10,144
We are a small family run business with over 20 years experience in brickwork, bathroom/kitchen fitting, roofing, landscaping, fencing, tiling and ...
From £9,752
Park Building Services Ltd is a trusted extension builder serving customers in SO18 and the surrounding area. Contact us to today to get a competit...
From £9,768
TP Developments are here to help customers who need an Extension Builder in SO18. We offer a competitive rate to complete all your extension builde...
From £10,144
Bailey Construction Services are here to help customers who need an Extension Builder in SO18. We offer a competitive rate to complete all your ext...
From £9,752
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £10,120
Need to find an Extension Builder near you for all your extension buildering work?
Mobile Services provides a local, trusted extension buil...
From £10,192
We are a Design and Build company based in Hampshire. Proud of our roots, we try to be the very best in the way we go about our business. Friendly...
From £10,136
Claytons Building and Roofing are here to help customers who need an Extension Builder in SO18. We offer a competitive rate to complete all your ex...
From £9,960
ROB DINE CONSTRUCTION is an established and experienced local extension builder in SO18. Please contact us for a free, no obligation quote and comp...

Outbuilding costs in SO18 range from the cheapest of £9,752 (Park Building Services Ltd based in PO9) to the dearest of £11,096 (R&B Property Improvements based in PO9), but these are just estimates.
Comparing extension builders estimates for building an outbuilding gives you an idea of who will be better value, but the best way to compare costs is to get actual quotes.
Get rates and quotes to build an outbuilding in SO18 by posting a job with HaMuch and we will send it to extension builders.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Outbuilding near Southampton | £34 | £243 |
| Outbuilding near Hedge End | £34 | £244 |
| Outbuilding near Eastleigh | £34 | £244 |
| Outbuilding near Chandler's Ford | £34 | £245 |
| Outbuilding near Locks Heath | £33 | £240 |
| Outbuilding near Totton | £34 | £243 |
| Outbuilding near Romsey | £32 | £230 |
| Outbuilding near Fareham | £35 | £250 |
| Outbuilding near Winchester | £37 | £266 |
| Outbuilding near Lee-on-the-Solent | £35 | £249 |
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 - £17,606

Two storey extension - £88,160

Build a timber frame extension - £26,106

Build a swimming pool - £81,106

Single storey extension - £57,128

Side return extension - £42,697

Install an RSJ - £2,306

Outbuilding - £10,106

Build a Mansard loft conversion - £52,106

Loft conversion - £34,748

Build a kitchen extension - £42,106

Hip to gable loft conversion - £42,106

Granny annexe - £87,106

Garden office - £10,106

Convert a Garage - £16,106

Garage - £18,606

Build a flat roof extension - £22,106

Build a dormer loft conversion - £42,106

Concrete foundations - £6,356

Convert a bungalow loft - £29,106

Convert a basement - £38,697