Find a builder to make your building structurally sound

RSJs support your new extension or other construction to ensure that your property is structurally sound. They are crucial parts of your building work that mustn't be ignored, and must be installed by a professional. 

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Install an RSJ cost in City Of Westminster

J&J Building Solutions

From £2,248

(rates verified 18/09/26)

Experienced extension builder ready to quote for your work. J&J Building Solutions is the best extension builder in City Of Westminster. No obligat...

T M Builder

From £2,512

(last active 24/09/26)

Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...

Derryard Construction Ltd

From £2,400

(last active 24/09/26)

Relax... you have found a reliable extension builder in City Of Westminster. Derryard Construction Ltd is a friendly and reliable company based in ...

B J CULLEN BUILDERS

From £2,168

(last active 24/09/26)

B J CULLEN BUILDERS are here to help customers who need an Extension Builder in City Of Westminster. We offer a competitive rate to complete all yo...

Major Building Contractors Ltd

From £2,232

(last active 24/09/26)

Relax... you have found a reliable extension builder in City Of Westminster. Major Building Contractors Ltd is a friendly and reliable company base...

Sz Builders

From £2,384

(last active 24/09/26)

Need to find an Extension Builder near you for all your extension buildering work?

Sz Builders provides a local, trusted extension builderi...

Render

From £2,912

(last active 24/09/26)

Experienced extension builder ready to quote for your work. Render is the best extension builder in City Of Westminster. No obligation free quotes ...

Jhon

From £2,096

(last active 24/09/26)

Experienced extension builder ready to quote for your work. Jhon is the best extension builder in City Of Westminster. No obligation free quotes an...

Can design and Construction

From £2,080

Member since August 2025

Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...

Torrington

From £2,392

(last active 24/09/26)

NIECEIC / NAAPIT GASSAFE WATER REGULATIONS We offer services towards completion of high end construction projects to dis...

RSJ cost in City Of Westminster

Estimates for install an rsj near City Of Westminster

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in City Of Westminster it ranges from £2,080 (Can design and Construction based in Ig11) to £2,912 (Render based in IG1).

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 City Of Westminster by posting a job with HaMuch and we will send it to extension builders in City Of Westminster.

"RSJ re-installation" - N16, job posted 04/10/25


Get extension builder rates instantly

Get extension builder rates instantly (excluding VAT or callout charges)
Location in UKHourly RateDaily Rate
Install An RSJ near London£45£274
Install An RSJ near Camden Town£44£277
Install An RSJ near Belgravia£44£276
Install An RSJ near Chelsea£44£276
Install An RSJ near Lambeth£44£275
Install An RSJ near Kensington£44£277
Install An RSJ near Islington£45£276
Install An RSJ near Fulham£44£277
Install An RSJ near Camberwell£44£276
Install An RSJ near Bethnal Green£45£276

Estimates for common extension builder jobs in City Of Westminster;

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.

More extensions & conversions cost guides...