From £2,632
Clapton, E5
Relax... you have found a reliable extension builder in E5. ISE Services is a friendly and reliable company based in E5 who consider no job as too ...
From £2,448
At Building Services Contractors we pride ourselves on an efficient and friendly service, and strive to achieve 100% customer satisfaction.
From £2,456
London, E5
I am an enthusiastic and effective project manager, willing to flex what I can do to suit you and your project. The best projects are in the planni...
From £2,656
D B Duri Building are here to help customers who need an Extension Builder in E5. We offer a competitive rate to complete all your extension builde...
From £2,392
Trusted and professional extension builder in E5. Experienced in all extension buildering work and keeping within budget and on quote. Amastic Roof...
From £2,344
FISKA DESIGN & BUILD are here to help customers who need an Extension Builder in E5. We offer a competitive rate to complete all your extension bui...
From £2,392
Carland Builders Ltd are here to help customers who need an Extension Builder in E5. We offer a competitive rate to complete all your extension bui...
From £2,304
Experienced extension builder ready to quote for your work. Barnaby Reynolds Design. is the best extension builder in E5. No obligation free quotes...
From £2,520
Relax... you have found a reliable extension builder in E5. Carbin Canopy is a friendly and reliable company based in E5 who consider no job as too...
From £2,536
Need to find an Extension Builder near you for all your extension buildering work?
UCDB Ltd provides a local, trusted extension buildering ...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in E5 it ranges from £2,304 (Barnaby Reynolds Design. based in N16) to £2,656 (D B Duri Building based in E8).
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 E5 by posting a job with HaMuch and we will send it to extension builders in E5.
"RSJ re-installation" - N16, job posted 04/10/25
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 - £17,768

Two storey extension - £88,402

Build a timber frame extension - £26,268

Build a swimming pool - £81,268

Single storey extension - £60,360

Side return extension - £44,515

Install an RSJ - £2,468

Outbuilding - £10,268

Build a Mansard loft conversion - £52,268

Loft conversion - £36,263

Build a kitchen extension - £42,268

Hip to gable loft conversion - £42,268

Granny annexe - £87,268

Garden office - £10,268

Convert a Garage - £16,268

Garage - £18,768

Build a flat roof extension - £22,268

Build a dormer loft conversion - £42,268

Concrete foundations - £6,518

Convert a bungalow loft - £29,268

Convert a basement - £40,515