John Smoth
Trusted and professional extension builder in Derby. Experienced in all extension buildering work and keeping within budget and on quote. Seerey an...
Alsn Askey
Experienced extension builder ready to quote for your work. Alan Askey Builder is the best extension builder in Derby. No obligation free quotes an...
From £2,096
Derbyshire Bathrooms & Kitchens Ltd is an established and experienced local extension builder in Derby. Please contact us for a free, no obligation...
From £2,312
Need to find an Extension Builder near you for all your extension buildering work?
J Pearson Building provides a local, trusted extension b...
From £2,104
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £1,952
Fitted Solutions was established in 2006 by founder Sam Fisher; with a promise to deliver exceptional craftmanship combined with first class custom...
From £1,944
The Blackbrook Group offers a one-stop shop for your construction project. We offer support from concept through to completion. We start with an in...
From £2,064
Nestled in the rolling hillside of the West Midlands, Derby is a city birthed by the Roman Empire, and grown in the industrial revolution. Initiall...
From £1,976
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £1,848
Experienced extension builder ready to quote for your work. REYNOLDS BUILDING SERVICES LTD is the best extension builder in Derby. No obligation fr...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Derby it ranges from £1,848 (Alan Askey Builder based in DE5) to £2,464 (Seerey and Smith Building Solutions based in DE7).
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 Derby by posting a job with HaMuch and we will send it to extension builders in Derby.
"RSJ installation" - DERBY, job posted 07/11/25
"RSJ installation Remove wall between kitchen and utility. Fit 3.4m steel beam Obtain Building Control approval and aign off" - DE3, job posted 01/01/70
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Derby | £29 | £227 |
| Install An RSJ near Erewash | £31 | £234 |
| Install An RSJ near Amber Valley | £32 | £244 |
| Install An RSJ near Belper | £32 | £244 |
| Install An RSJ near Ilkeston | £31 | £236 |
| Install An RSJ near Heanor | £31 | £236 |
| Install An RSJ near Long Eaton | £32 | £249 |
| Install An RSJ near Ripley | £32 | £246 |
| Install An RSJ near Broxtowe | £34 | £240 |
| Install An RSJ near Burton upon Trent | £33 | £257 |
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 - £17,361

Two storey extension - £87,791

Build a timber frame extension - £25,861

Build a swimming pool - £80,861

Single storey extension - £52,216

Side return extension - £39,934

Install an RSJ - £2,061

Outbuilding - £9,861

Build a Mansard loft conversion - £51,861

Loft conversion - £32,445

Build a kitchen extension - £41,861

Hip to gable loft conversion - £41,861

Granny annexe - £86,861

Garden office - £9,861

Convert a Garage - £15,861

Garage - £18,361

Build a flat roof extension - £21,861

Build a dormer loft conversion - £41,861

Concrete foundations - £6,111

Convert a bungalow loft - £28,861

Convert a basement - £35,934