Published by Build Hub Company Limited · Updated
The bar schedule decides, not the yard
Reinforcement diameters come from the structural engineer's design and are set out on the bar bending schedule. The schedule states the bar mark, diameter, shape, length, number of bars and where they sit. A supplier's job is to deliver the diameters and tonnage that schedule calls for — not to reinterpret it.
If a size is unavailable, that is a question for the engineer, because area of steel, bar spacing, cover and lap length all change together. Substituting on site is how a slab or column quietly ends up under-reinforced.
What the common diameters are typically used for
These are typical uses, not a design rule. The same diameter can be used very differently between a coastal villa, a hotel frame and a retaining structure.
- Y8 — links and stirrups in beams and columns, light slab mesh replacement, secondary distribution steel
- Y10 — slab reinforcement, lighter beam bars, ring beams and lintels on smaller spans
- Y12 — main bars in beams, columns and slabs on typical residential and small commercial frames
- Y16 — heavier column and beam bars, transfer elements, foundations and longer spans
- BRC / mesh sheets — slabs on grade, screeds and hardstanding where a designed mesh is specified
- Binding wire — tying the cage so it holds position during pouring; not a structural element
Tonnes, pieces and how steel is actually quoted
Reinforcement is traded by weight, while a bar schedule is written in pieces and lengths. Converting between them is where quantities are commonly lost. Build Hub quotes deformed bar per tonne — currently indicative rates of TZS 2,600,000 per tonne for Y8, Y10 and Y12 and TZS 2,700,000 per tonne for Y16 — and can convert a schedule into tonnage so the order matches the drawing.
Send the bar schedule, or the diameters, lengths and piece counts, and state whether you want the quote in tonnes, pieces or both.
Cover, laps and the coastal factor
In a marine environment, concrete cover is what protects steel from chloride attack. Insufficient cover, chairs and spacers omitted, or bars pushed out of position during pouring will shorten the life of the structure far more quickly than an inland equivalent.
Laps and anchorage lengths belong to the design. Cutting laps short to save steel is a structural change, not a saving.
Receiving and storing bar on site
- Check diameters and bundle counts against the delivery note before offloading
- Store off the ground on timber or blocks, away from standing water and salt spray
- Keep light surface rust in perspective — loose flaking scale is a problem, a light patina generally is not
- Keep cut and bent bars marked by bar mark so they are placed where the schedule intends