BeautifulRenovation are here to help customers who need an Extension Builder in SL4. We offer a competitive rate to complete all your extension bui...
MRE Maintenance Services is an established and experienced local extension builder in SL4. Please contact us for a free, no obligation quote and co...
BDR Home Improvement are here to help customers who need an Extension Builder in SL4. We offer a competitive rate to complete all your extension bu...
Experienced extension builder ready to quote for your work. Sherry Construction is the best extension builder in SL4. No obligation free quotes and...
EIC Builders Ltd are here to help customers who need an Extension Builder in SL4. We offer a competitive rate to complete all your extension builde...
EGPM LTD are here to help customers who need an Extension Builder in SL4. We offer a competitive rate to complete all your extension buildering job...
Experienced extension builder ready to quote for your work. Rai Builders is the best extension builder in SL4. No obligation free quotes and many h...
Ani Mokashi is an established and experienced local extension builder in SL4. Please contact us for a free, no obligation quote and competitive rat...
Mario
Trusted and professional extension builder in SL4. Experienced in all extension buildering work and keeping within budget and on quote. Mario Polis...
Dub Solutions is a trusted extension builder serving customers in SL4 and the surrounding area. Contact us to today to get a competitive quote for ...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in SL4 it ranges from £2,128 (Rai Builders based in SL2) to £2,560 (Ani Mokashi based in SL4).
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 SL4 by posting a job with HaMuch and we will send it to extension builders in SL4.
"RSJ installation" - SLOUGH, job posted 05/07/25
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Windsor | £41 | £271 |
| Install An RSJ near Windsor & Maidenhead | £42 | £272 |
| Install An RSJ near Slough | £42 | £272 |
| Install An RSJ near Egham | £42 | £266 |
| Install An RSJ near Ascot | £41 | £276 |
| Install An RSJ near Maidenhead | £41 | £273 |
| Install An RSJ near Staines-upon-Thames | £42 | £269 |
| Install An RSJ near Bracknell Forest | £41 | £287 |
| Install An RSJ near Bracknell | £41 | £285 |
| Install An RSJ near Gerrards Cross | £43 | £282 |
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 - £17,603

Two storey extension - £88,155

Build a timber frame extension - £26,103

Build a swimming pool - £81,103

Single storey extension - £57,064

Side return extension - £42,661

Install an RSJ - £2,303

Outbuilding - £10,103

Build a Mansard loft conversion - £52,103

Loft conversion - £34,718

Build a kitchen extension - £42,103

Hip to gable loft conversion - £42,103

Granny annexe - £87,103

Garden office - £10,103

Convert a Garage - £16,103

Garage - £18,603

Build a flat roof extension - £22,103

Build a dormer loft conversion - £42,103

Concrete foundations - £6,353

Convert a bungalow loft - £29,103

Convert a basement - £38,661