From £2,008
BOWIE CONSTRUCTION LTD is a trusted extension builder serving customers in CB21 and the surrounding area. Contact us to today to get a competitive ...
From £2,544
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £2,416
Trusted and professional extension builder in CB21. Experienced in all extension buildering work and keeping within budget and on quote. DEBRAY BUI...
From £3,560
Experienced extension builder ready to quote for your work. ALLIED BUILDING ASSOCIATES LTD is the best extension builder in CB21. No obligation fre...
From £2,272
Relax... you have found a reliable extension builder in CB21. D Stebbings is a friendly and reliable company based in CB21 who consider no job as t...
From £2,136
TSN Consultants Ltd are here to help customers who need an Extension Builder in CB21. We offer a competitive rate to complete all your extension bu...
From £2,304
Relax... you have found a reliable extension builder in CB21. Pinnacle Construction is a friendly and reliable company based in CB21 who consider n...
From £2,424
SP-Building Services Ltd is an established and experienced local extension builder in CB21. Please contact us for a free, no obligation quote and c...
From £2,576
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £2,352
Relax... you have found a reliable extension builder in CB21. CROWNBUILD is a friendly and reliable company based in CB21 who consider no job as to...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in CB21 it ranges from £2,008 (BOWIE CONSTRUCTION LTD based in CB21) to £3,560 (ALLIED BUILDING ASSOCIATES LTD based in CB22).
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 CB21 by posting a job with HaMuch and we will send it to extension builders in CB21.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Haverhill | £37 | £260 |
| Install An RSJ near Cambridge | £38 | £271 |
| Install An RSJ near South Cambridgeshire | £43 | £305 |
| Install An RSJ near Ely | £40 | £279 |
| Install An RSJ near Sudbury | £34 | £229 |
| Install An RSJ near Bishop's Stortford | £42 | £264 |
| Install An RSJ near Bury St Edmunds | £34 | £251 |
| Install An RSJ near Braintree | £37 | £247 |
| Install An RSJ near East Hertfordshire | £44 | £289 |
| Install An RSJ near Biggleswade | £41 | £268 |
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 - £17,759

Two storey extension - £88,389

Build a timber frame extension - £26,259

Build a swimming pool - £81,259

Single storey extension - £60,184

Side return extension - £44,416

Install an RSJ - £2,459

Outbuilding - £10,259

Build a Mansard loft conversion - £52,259

Loft conversion - £36,180

Build a kitchen extension - £42,259

Hip to gable loft conversion - £42,259

Granny annexe - £87,259

Garden office - £10,259

Convert a Garage - £16,259

Garage - £18,759

Build a flat roof extension - £22,259

Build a dormer loft conversion - £42,259

Concrete foundations - £6,509

Convert a bungalow loft - £29,259

Convert a basement - £40,416