From £1,864
Need an Extension Builder in St Helens? KMC Brickwork has been helping local clients (20 mile radius) with their extension buildering jobs for many...
From £1,808
Trusted and professional extension builder in St Helens. Experienced in all extension buildering work and keeping within budget and on quote. M L R...
From £2,072
G. Finnigan Builders is an established extension buildering business in St Helens. We come highly recommended and provide competitive quotes for yo...
From £2,080
Need to find an Extension Builder near you for all your extension buildering work?
Leabra Construction North West Ltd provides a local, tru...
From £1,424
MJ Barker & Son is an established extension buildering business in St Helens. We come highly recommended and provide competitive quotes for your wo...
From £2,232
Hello, I am Allan. I have run Allan Rowe Property Services since September 2014. I am based in Newton Le Willows and provide a wide range of proper...
From £2,096
HIGHTOWN CONSTRUCTION LTD is an established extension buildering business in St Helens. We come highly recommended and provide competitive quotes f...
From £2,000
Higher End Construction Limited is an established extension buildering business in St Helens. We come highly recommended and provide competitive qu...
From £2,064
Need to find an Extension Builder near you for all your extension buildering work?
Maintenance Point provides a local, trusted extension bu...
From £2,024
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in St Helens it ranges from £1,424 (MJ Barker & Son based in WA11) to £2,232 (Allan Rowe Property Services based in WA12).
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 St Helens by posting a job with HaMuch and we will send it to extension builders in St Helens.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near St Helens | £31 | £224 |
| Install An RSJ near Prescot | £31 | £223 |
| Install An RSJ near Knowsley | £31 | £222 |
| Install An RSJ near Newton-le-Willows | £31 | £221 |
| Install An RSJ near Huyton with Roby | £31 | £225 |
| Install An RSJ near Ashton-in-Makerfield | £30 | £220 |
| Install An RSJ near Widnes | £31 | £220 |
| Install An RSJ near Golborne | £30 | £222 |
| Install An RSJ near Orrell | £29 | £214 |
| Install An RSJ near Kirkby | £31 | £223 |
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 - £17,266

Two storey extension - £87,650

Build a timber frame extension - £25,766

Build a swimming pool - £80,766

Single storey extension - £50,328

Side return extension - £38,872

Install an RSJ - £1,966

Outbuilding - £9,766

Build a Mansard loft conversion - £51,766

Loft conversion - £31,560

Build a kitchen extension - £41,766

Hip to gable loft conversion - £41,766

Granny annexe - £86,766

Garden office - £9,766

Convert a Garage - £15,766

Garage - £18,266

Build a flat roof extension - £21,766

Build a dormer loft conversion - £41,766

Concrete foundations - £6,016

Convert a bungalow loft - £28,766

Convert a basement - £34,872