Lee Townsend
Need to find an Extension Builder near you for all your extension buildering work?
Lp Townsend Brickwork provides a local, trusted extensio...
BeautifulRenovation are here to help customers who need an Extension Builder in Windsor. We offer a competitive rate to complete all your extension...
MRE Maintenance Services is an established and experienced local extension builder in Windsor. Please contact us for a free, no obligation quote an...
BDR Home Improvement are here to help customers who need an Extension Builder in Windsor. We offer a competitive rate to complete all your extensio...
Experienced extension builder ready to quote for your work. Sherry Construction is the best extension builder in Windsor. No obligation free quotes...
EIC Builders Ltd are here to help customers who need an Extension Builder in Windsor. We offer a competitive rate to complete all your extension bu...
B.A Ruffle Building Contractor is an established extension buildering business in Windsor. We come highly recommended and provide competitive quote...
HAMPTON CONSTRUCTION LTD are here to help customers who need an Extension Builder in Windsor. We offer a competitive rate to complete all your exte...
EGPM LTD are here to help customers who need an Extension Builder in Windsor. We offer a competitive rate to complete all your extension buildering...
Relax... you have found a reliable extension builder in Windsor. RODOF Ltd is a friendly and reliable company based in Windsor who consider no job ...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Windsor it ranges from £1,880 (Lp Townsend Brickwork based in SL2) to £2,584 (HAMPTON CONSTRUCTION LTD based in SL2).
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 Windsor by posting a job with HaMuch and we will send it to extension builders in Windsor.
"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 - £17,574

Two storey extension - £88,110

Build a timber frame extension - £26,074

Build a swimming pool - £81,074

Single storey extension - £56,472

Side return extension - £42,328

Install an RSJ - £2,274

Outbuilding - £10,074

Build a Mansard loft conversion - £52,074

Loft conversion - £34,440

Build a kitchen extension - £42,074

Hip to gable loft conversion - £42,074

Granny annexe - £87,074

Garden office - £10,074

Convert a Garage - £16,074

Garage - £18,574

Build a flat roof extension - £22,074

Build a dormer loft conversion - £42,074

Concrete foundations - £6,324

Convert a bungalow loft - £29,074

Convert a basement - £38,328