Relax... you have found a reliable extension builder in Hackney. London Trowel Co. is a friendly and reliable company based in Hackney who consider...
Hackney, E8
Trusted and professional extension builder in Hackney. Experienced in all extension buildering work and keeping within budget and on quote. Thermod...
Experienced extension builder ready to quote for your work. Five Star Builder is the best extension builder in Hackney. No obligation free quotes a...
Need the extension buildering job done quickly without breaking the bank? SH Enterprise offer fast, reliable, and affordable extension buildering s...
Torrington Design
NIECEIC / NAAPIT GASSAFE WATER REGULATIONS We offer services towards completion of high end construction projects to dis...
"Did callout made safe my elctrical work thanks" - reviewed 16/05/23, REECYRUSSO
Experienced extension builder ready to quote for your work. Glenward Builders Ltd is the best extension builder in Hackney. No obligation free quot...
Mick Singh
At Building Services Contractors we pride ourselves on an efficient and friendly service, and strive to achieve 100% customer satisfaction.
CK Constructions & Development Ltd is a trusted extension builder serving customers in Hackney and the surrounding area. Contact us to today to get...
GS Fabric Ltd is an established and experienced local extension builder in Hackney. Please contact us for a free, no obligation quote and competiti...
JM Building Services is a trusted extension builder serving customers in Hackney and the surrounding area. Contact us to today to get a competitive...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Hackney it ranges from £2,128 (GS Fabric Ltd based in E2) to £2,600 (Five Star Builder based in N16).
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 Hackney by posting a job with HaMuch and we will send it to extension builders in Hackney.
"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 - £17,668

Two storey extension - £88,252

Build a timber frame extension - £26,168

Build a swimming pool - £81,168

Single storey extension - £58,360

Side return extension - £43,390

Install an RSJ - £2,368

Outbuilding - £10,168

Build a Mansard loft conversion - £52,168

Loft conversion - £35,325

Build a kitchen extension - £42,168

Hip to gable loft conversion - £42,168

Granny annexe - £87,168

Garden office - £10,168

Convert a Garage - £16,168

Garage - £18,668

Build a flat roof extension - £22,168

Build a dormer loft conversion - £42,168

Concrete foundations - £6,418

Convert a bungalow loft - £29,168

Convert a basement - £39,390