From £2,392
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 £3,296
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 £2,344
We are a small family run business with over 20 years experience in brickwork, bathroom/kitchen fitting, roofing, landscaping, fencing, tiling and ...
From £1,968
TP Developments are here to help customers who need an Extension Builder in SO15. We offer a competitive rate to complete all your extension builde...
From £2,424
Elmer Building Services ltd is an established extension buildering business in SO15. We come highly recommended and provide competitive quotes for ...
From £2,344
Bailey Construction Services are here to help customers who need an Extension Builder in SO15. We offer a competitive rate to complete all your ext...
From £1,952
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £2,320
Need to find an Extension Builder near you for all your extension buildering work?
Mobile Services provides a local, trusted extension buil...
From £2,336
Claytons Building and Roofing are here to help customers who need an Extension Builder in SO15. We offer a competitive rate to complete all your ex...
From £2,160
ROB DINE CONSTRUCTION is an established and experienced local extension builder in SO15. Please contact us for a free, no obligation quote and comp...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in SO15 it ranges from £1,952 (Steve Lovett Builders based in SO18) to £3,296 (R&B Property Improvements based in PO9).
Comparing extension builders estimates for fitting an RSJ 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 install an RSJ in SO15 by posting a job with HaMuch and we will send it to extension builders in SO15.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Southampton | £34 | £243 |
| Install An RSJ near Totton | £34 | £243 |
| Install An RSJ near Eastleigh | £34 | £244 |
| Install An RSJ near Chandler's Ford | £34 | £245 |
| Install An RSJ near Hedge End | £34 | £244 |
| Install An RSJ near Romsey | £32 | £230 |
| Install An RSJ near Locks Heath | £33 | £240 |
| Install An RSJ near New Forest | £32 | £245 |
| Install An RSJ near Fareham | £35 | £250 |
| Install An RSJ near Winchester | £37 | £266 |
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 - £17,654

Two storey extension - £88,230

Build a timber frame extension - £26,154

Build a swimming pool - £81,154

Single storey extension - £58,072

Side return extension - £43,228

Install an RSJ - £2,354

Outbuilding - £10,154

Build a Mansard loft conversion - £52,154

Loft conversion - £35,190

Build a kitchen extension - £42,154

Hip to gable loft conversion - £42,154

Granny annexe - £87,154

Garden office - £10,154

Convert a Garage - £16,154

Garage - £18,654

Build a flat roof extension - £22,154

Build a dormer loft conversion - £42,154

Concrete foundations - £6,404

Convert a bungalow loft - £29,154

Convert a basement - £39,228