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 £2,016
Relax... you have found a reliable extension builder in DE21. Flying Tortise is a friendly and reliable company based in DE21 who consider no job a...
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 £2,000
Need to find an Extension Builder near you for all your extension buildering work?
BRICKON CONSTRUCTION LIMITED provides a local, trusted e...
From £1,904
A J Construction is an established and experienced local extension builder in DE21. Please contact us for a free, no obligation quote and competiti...
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 £2,064
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 £2,352
Experienced extension builder ready to quote for your work. Rowes Building Ltd is the best extension builder in DE21. No obligation free quotes and...
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 £2,464
Trusted and professional extension builder in DE21. Experienced in all extension buildering work and keeping within budget and on quote. Seerey and...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in DE21 it ranges from £1,904 (A J Construction based in DE22) 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 DE21 by posting a job with HaMuch and we will send it to extension builders in DE21.
"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 | £30 | £228 |
| Install An RSJ near Erewash | £31 | £233 |
| Install An RSJ near Ilkeston | £31 | £235 |
| Install An RSJ near Amber Valley | £31 | £238 |
| Install An RSJ near Belper | £32 | £244 |
| Install An RSJ near Heanor | £31 | £236 |
| Install An RSJ near Long Eaton | £32 | £248 |
| Install An RSJ near Ripley | £32 | £246 |
| Install An RSJ near Broxtowe | £33 | £240 |
| Install An RSJ near Nottingham | £34 | £241 |
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 - £17,411

Two storey extension - £87,867

Build a timber frame extension - £25,911

Build a swimming pool - £80,911

Single storey extension - £53,224

Side return extension - £40,501

Install an RSJ - £2,111

Outbuilding - £9,911

Build a Mansard loft conversion - £51,911

Loft conversion - £32,918

Build a kitchen extension - £41,911

Hip to gable loft conversion - £41,911

Granny annexe - £86,911

Garden office - £9,911

Convert a Garage - £15,911

Garage - £18,411

Build a flat roof extension - £21,911

Build a dormer loft conversion - £41,911

Concrete foundations - £6,161

Convert a bungalow loft - £28,911

Convert a basement - £36,501