From £1,600
T.I Building is a trusted extension builder serving customers in Randalstown and the surrounding area. Contact us to today to get a competitive quo...
From £1,632
We have over 25 years experience in all building work and renowned for good workmanship All jobs small and large taken on
From £2,104
FJS CONTRACTS LTD are here to help customers who need an Extension Builder in Randalstown. We offer a competitive rate to complete all your extensi...
From £2,216
Seamus Mcmullan building and joinery is an established extension buildering business in Randalstown. We come highly recommended and provide competi...
From £1,568
Relax... you have found a reliable extension builder in Randalstown. SM Plumbing & Heating is a friendly and reliable company based in Randalstown ...
From £1,496
Been in business as 18 years alway put clients first and never had any combacks
From £1,536
Trusted and professional extension builder in Randalstown. Experienced in all extension buildering work and keeping within budget and on quote. Bel...
From £1,496
Ballantine building solutions is an established extension buildering business in Randalstown. We come highly recommended and provide competitive qu...
From £1,576
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 Randalstown it ranges from £1,496 (Oakmore Contracts based in BT45) to £2,760 (Build a Boiler based in BT67).
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 Randalstown by posting a job with HaMuch and we will send it to extension builders in Randalstown.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Install An RSJ near Crumlin | £26 | £194 |
| Install An RSJ near Ballyclare | £20 | £124 |
| Install An RSJ near Magherafelt | £30 | £238 |
| Install An RSJ near Maghaberry | £31 | £205 |
| Install An RSJ near Greenisland | £23 | £153 |
| Install An RSJ near Belfast | £23 | £161 |
| Install An RSJ near Lisburn | £24 | £164 |
| Install An RSJ near Carrickfergus | £23 | £158 |
| Install An RSJ near Hillsborough and Culcavy | £25 | £170 |
| Install An RSJ near Larne | £15 | £122 |
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 - £17,098

Two storey extension - £87,398

Build a timber frame extension - £25,598

Build a swimming pool - £80,598

Single storey extension - £46,968

Side return extension - £36,982

Install an RSJ - £1,798

Outbuilding - £9,598

Build a Mansard loft conversion - £51,598

Loft conversion - £29,985

Build a kitchen extension - £41,598

Hip to gable loft conversion - £41,598

Granny annexe - £86,598

Garden office - £9,598

Convert a Garage - £15,598

Garage - £18,098

Build a flat roof extension - £21,598

Build a dormer loft conversion - £41,598

Concrete foundations - £5,848

Convert a bungalow loft - £28,598

Convert a basement - £32,982