If you are planning a basement, extension or new build in London, the reinforcement quote can be confusing. Steel fixing is usually priced per tonne, but that number changes a lot depending on the bar sizes, the site and who supplies the steel. This guide explains what a fair price looks like and why quotes for the same job can differ.
Steel fixing is quoted in two main ways. With labour only, you or your main contractor buy the steel and the fixer charges to cut, place and tie it. With supply and fix, the contractor orders the scheduled bar and mesh, has it delivered and fixes it.
Across London and the home counties, labour-only fixing on straightforward residential work tends to fall somewhere between £300 and £550 per tonne. Supply and fix usually lands between roughly £1,100 and £1,700 per tonne, because steel prices move with the market. Treat these as starting points rather than fixed prices. The drawings and the site decide the real figure.
A tonne of 10mm or 12mm bar contains far more individual bars and tie points than a tonne of 25mm bar. More bars means more handling, more tying and more time, so lighter bar costs more per tonne to fix. A raft slab using mostly H12 at close centres can cost noticeably more per tonne than a pile cap full of H25 and H32.
Mesh such as A393 or A252 is usually quicker to lay than loose bar, which can bring the per tonne labour cost down on ground-bearing slabs. Ask your fixer to price from the bar bending schedule (normally drawn up to BS 8666) so everyone is quoting on the same tonnage and bar mix.
The same job can cost more in Islington or Fulham than in an open plot in outer Hertfordshire, and usually for practical reasons rather than a London premium for its own sake.
Basement extensions under terraced houses are a good example. Steel often has to be carried through the house or passed down a light well by hand, the working space is tight, and the work happens in stages as underpinning sections are dug and cast. All of that slows the fixing down.
A clear quote should state the tonnage it is based on, whether it is labour only or supply and fix, and which parts of the structure are covered. It should say who provides spacers, chairs and tying wire, who handles offloading, and whether waiting time or return visits are charged.
Make sure the steel is ready for inspection before concrete is ordered. Building control or your structural engineer will usually want to check the reinforcement before a pour, and a fixer who works to the drawings and has the cover and laps right saves you from a delayed or wasted concrete delivery.
Get your engineer's drawings and bar schedule finished before asking for prices, as quotes based on guesswork tend to include padding for risk. Group work together where you can, since one longer visit is cheaper than several short ones. Ask at least two or three fixers to price from the same information, and compare what is included rather than just the headline rate per tonne.
Sometimes, but not always. Fixing contractors often have trade accounts with London suppliers, and buying it yourself means you carry the risk of wrong deliveries or shortages holding up the job.
Basements usually involve lighter bars at close spacing, staged pours and restricted access, all of which take more labour per tonne. Retaining walls and starter bars also need careful setting out, which adds time.
It varies widely with the design, but a single-storey basement under a terraced house often needs somewhere between 3 and 10 tonnes. Your structural engineer's bar schedule will give the exact figure.
Tell us the project, programme and scope, and whether you need supply, fix or both. We will come back to you.