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Cross-market term

Reinforcement / rebar

Steel bars or fabric cast into concrete to carry the tension the concrete cannot, placed to a schedule stating each bar's size, shape, position and cover.
  • 4Markets
  • YesSame thing everywhere
  • 6Calculators

What it is called, by market

One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.

  • United Statesyours

    Same thing

    rebar

    also reinforcing steel, reinforcing bar

  • Canada

    Same thing

    rebar

    also reinforcing steel

  • United Kingdom

    Same thing

    reinforcement

    also rebar, reinforcement bar

    "Rebar" is understood and used in Britain too; "reinforcement" is the formal term, and the one BS 8666 schedules are written in.

  • Australia

    Same thing

    reinforcement

    also reo, rebar

    "Reo" is common Australian site shorthand, including "reo mesh" for fabric.

The governing standard, by market

  • United States

    ACI 318

    Structural concrete design including reinforcement detailing.

  • United Kingdom

    BS 8666

    Scheduling, dimensioning, bending and cutting of steel reinforcement — the schedule's own format and shape codes.

  • Australia

    AS 3600

    Concrete structures design.

Calculators for this

Each works in either measurement system, and the terminology on the page follows whichever market you have selected.

Rebar Calculator →Rebar Lap Splice Length Calculator (ACI 318) →Rebar Development Length Calculator (ACI 318) →Concrete Slab + Rebar Combined Mass Calculator →Seismic Masonry Horizontal Reinforcement Ratio Calculator →Rebar Weight Calculator →

Frequently asked questions

Are bar sizes the same across markets?
No, and the numbering conventions are not even the same kind of number. Imperial bar designations in the United States are based on eighths of an inch of nominal diameter, so a #4 bar is roughly half an inch. Metric designations in Britain, Australia and most of the world state the nominal diameter in millimetres directly, so a 12 mm bar is 12 mm. There is also a soft-metric American designation that restates the imperial sizes in millimetres, which is a third set of labels for the same physical bars. A substitution between systems is therefore a design decision about area and spacing rather than a lookup, and the bar shape codes in a schedule are equally market-specific.
What is a bar schedule, and why is its format a standard?
It is the document telling a fabricator exactly what to make: every bar's mark, size, shape code, dimensions, quantity and location. The format is standardised because the shape codes are a shared language between designer, fabricator and steel fixer — a code identifies a bending configuration with its dimensions given in a defined order, and a misread code produces bars of the right length and the wrong shape. Britain's is BS 8666, which is why a British schedule looks unfamiliar to a reader from another market even when every dimension on it is legible: the shape codes are the part that does not translate, and reading them as if they were another system's is how a whole delivery goes wrong.
Is mesh called the same thing everywhere?
No. The welded sheet of bars used in slabs is welded wire reinforcement or welded wire fabric in the United States and Canada, mesh or fabric in Britain — where the standard designations run A, B and C series by wire size and spacing — and reo mesh in Australian site usage. The designations are market-specific in the same way bar sizes are, so a British A-series designation has no direct American equivalent and vice versa. The other thing that differs is how it is supplied: sheets in some markets, rolls in others, which changes the lap arrangement, the waste and the handling on site rather than the design.