From £2,200
Need an Extension Builder in Holloway? Bok Services Ltd has been helping local clients (5 mile radius) with their extension buildering jobs for man...
From £2,184
Holloway, N7
Andreas Thomas Demetri is a trusted extension builder serving customers in Holloway and the surrounding area. Contact us to today to get a competit...
From £2,160
Experienced extension builder ready to quote for your work. D.W Baker is the best extension builder in Holloway. No obligation free quotes and many...
From £2,104
London, N7
Experienced extension builder ready to quote for your work. Nucleus Design Studio is the best extension builder in Holloway. No obligation free quo...
From £2,432
After spending 15 years working across various private practices, Richard decided to take the plunge and set up his own architecture and design com...
From £2,616
CMT Ltd is an established extension buildering business in Holloway. We come highly recommended and provide competitive quotes for your work.
From £2,088
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
From £2,336
Our building services company Brothers Group have been helping customers in North, East and West London and the surrounding area by providing profe...
From £2,104
JAMES REGAN CONSTRUCTION is a trusted extension builder serving customers in Holloway and the surrounding area. Contact us to today to get a compet...
From £2,536
Mel Massey Studio, based in Finsbury Park, North London, offers interior design, interior styling and project management. With over 10 years of exp...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Holloway it ranges from £2,088 (Warren House Construction Ltd based in N19) to £2,616 (CMT Ltd based in N1).
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 Holloway by posting a job with HaMuch and we will send it to extension builders in Holloway.
"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 - £17,576

Two storey extension - £88,114

Build a timber frame extension - £26,076

Build a swimming pool - £81,076

Single storey extension - £56,520

Side return extension - £42,355

Install an RSJ - £2,276

Outbuilding - £10,076

Build a Mansard loft conversion - £52,076

Loft conversion - £34,463

Build a kitchen extension - £42,076

Hip to gable loft conversion - £42,076

Granny annexe - £87,076

Garden office - £10,076

Convert a Garage - £16,076

Garage - £18,576

Build a flat roof extension - £22,076

Build a dormer loft conversion - £42,076

Concrete foundations - £6,326

Convert a bungalow loft - £29,076

Convert a basement - £38,355