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Trusted and professional extension builder in Southampton. Experienced in all extension buildering work and keeping within budget and on quote. And...
Arshad Ali
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...
ROB DINE CONSTRUCTION is an established and experienced local extension builder in Southampton. Please contact us for a free, no obligation quote a...
Need to find an Extension Builder near you for all your extension buildering work?
Mobile Services provides a local, trusted extension buil...
Southampton, SO19
Claytons Building and Roofing are here to help customers who need an Extension Builder in Southampton. We offer a competitive rate to complete all ...
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
Luke Rees
General Building Services (Southampton) Ltd is a trusted extension builder serving customers in Southampton and the surrounding area. Contact us to...
Experienced extension builder ready to quote for your work. CSY Construction Ltd is the best extension builder in Southampton. No obligation free q...
Anthony Withey
Southampton, SO31
Trusted and professional extension builder in Southampton. Experienced in all extension buildering work and keeping within budget and on quote. A W...
Experienced extension builder ready to quote for your work. Grant Construction is the best extension builder in Southampton. No obligation free quo...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Southampton it ranges from £1,952 (Steve Lovett Builders based in SO18) to £2,392 (AAConcepts based in SO14).
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 Southampton by posting a job with HaMuch and we will send it to extension builders in Southampton.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Southampton | £34 | £243 |
| Install An RSJ near Eastleigh | £34 | £244 |
| Install An RSJ near Totton | £34 | £243 |
| Install An RSJ near Hedge End | £34 | £244 |
| Install An RSJ near Chandler's Ford | £34 | £245 |
| Install An RSJ near Locks Heath | £33 | £240 |
| Install An RSJ near Romsey | £32 | £230 |
| Install An RSJ near New Forest | £32 | £245 |
| Install An RSJ near Fareham | £35 | £250 |
| Install An RSJ 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 - £17,541

Two storey extension - £88,061

Build a timber frame extension - £26,041

Build a swimming pool - £81,041

Single storey extension - £55,816

Side return extension - £41,959

Install an RSJ - £2,241

Outbuilding - £10,041

Build a Mansard loft conversion - £52,041

Loft conversion - £34,133

Build a kitchen extension - £42,041

Hip to gable loft conversion - £42,041

Granny annexe - £87,041

Garden office - £10,041

Convert a Garage - £16,041

Garage - £18,541

Build a flat roof extension - £22,041

Build a dormer loft conversion - £42,041

Concrete foundations - £6,291

Convert a bungalow loft - £29,041

Convert a basement - £37,959