From £2,240
RAS Construction & Design Ltd is a well established company specialising in all aspects of extensions, loft conversions, general building, renovati...
From £2,048
Ask Windows Limited is an established and experienced local extension builder in Mill Hill. Please contact us for a free, no obligation quote and c...
From £2,352
Trusted and professional extension builder in Mill Hill. Experienced in all extension buildering work and keeping within budget and on quote. MH Co...
From £2,200
TSCR Construction are here to help customers who need an Extension Builder in Mill Hill. We offer a competitive rate to complete all your extension...
From £1,608
DBR Construction Ltd are here to help customers who need an Extension Builder in Mill Hill. We offer a competitive rate to complete all your extens...
From £2,568
NW London Contracts Ltd are here to help customers who need an Extension Builder in Mill Hill. We offer a competitive rate to complete all your ext...
From £1,960
Hi everyone!
i have good experience over 25 years working in construction and I have my on Business and my company
From £1,864
With over 24 years of hands-on experience, FC Builders London Ltd specialises in home extensions, loft conversions, full renovations, kitchen and b...
From £2,592
Coldshield ltd are here to help customers who need an Extension Builder in Mill Hill. We offer a competitive rate to complete all your extension bu...
From £2,120
NISUP BUILDING SERVICES Company specializes in the domestic and commercial building industry :1. Refurbishm...

How much RSJs cost for supply and installation varies depending on the size, type and load-bearing properties, but in Mill Hill it ranges from £1,608 (DBR Construction Ltd based in NW7) to £2,592 (Coldshield ltd based in NW7).
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 Mill Hill by posting a job with HaMuch and we will send it to extension builders in Mill Hill.
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 - £17,455

Two storey extension - £87,933

Build a timber frame extension - £25,955

Build a swimming pool - £80,955

Single storey extension - £54,104

Side return extension - £40,996

Install an RSJ - £2,155

Outbuilding - £9,955

Build a Mansard loft conversion - £51,955

Loft conversion - £33,330

Build a kitchen extension - £41,955

Hip to gable loft conversion - £41,955

Granny annexe - £86,955

Garden office - £9,955

Convert a Garage - £15,955

Garage - £18,455

Build a flat roof extension - £21,955

Build a dormer loft conversion - £41,955

Concrete foundations - £6,205

Convert a bungalow loft - £28,955

Convert a basement - £36,996