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Reinforcing steel or mesh

Updated: 23 October 2026

You have a ground-bearing slab to pour, or a narrow trench, and both the loose bar and the welded sheet are being called rebar. Reinforcing steel or mesh is the choice between a ribbed bar to BS 4449 and a fabric sheet to BS 4483. A pack of 6 mm bar is not a sheet of A142. The [reinforcing steel comparison](/hub/diy-supplies/reinforcing-steel) only lists loose bar, so this page does not rank a mesh listing or invent a sheet price. Products Compared used the Concrete Society, a CARES fabric table presented as BS 4483:2025, and LABC. We did not test a slab. A purchase through our links may earn a commission at no extra cost to you.

You have a ground-bearing slab to pour, or a narrow trench, and both the loose bar and the welded sheet are being called rebar.

Our top picks

Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m

Best overall

Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m
9.2/10about £25.20
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Just The Job Supplies Just The Job 10 mm bar, 2 × 1 m

Alternative

Just The Job Supplies Just The Job 10 mm bar, 2 × 1 m
9.0/10about £12.26
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Just The Job Supplies Just The Job 6 mm bar, 10 × 1 m

Alternative

Just The Job Supplies Just The Job 6 mm bar, 10 × 1 m
9.0/10about £21.73
View offer
On this page
  1. 1.A sheet and a bar are different products
  2. 2.What A142 is for, and what it does not do
  3. 3.When the drawing wants loose bar
  4. 4.What to refuse

A sheet and a bar are different products

Loose reinforcing steel is one ribbed bar. Fabric is a welded grid. The Concrete Society sorts sheets as A, square mesh at 200 mm for slabs; B, structural fabric; C, long fabric; and D, wrapping mesh. Standard sheets are 2.4 m by 4.8 m. A142, on the CARES table from BS 4483:2025, is 6 mm wires at 200 mm centres, 142 mm² each way per metre, and 2.22 kg per square metre, on a 4.8 m by 2.4 m sheet. The loose 6 mm pack here is B09PRTY1B2, ten 1 m bars at £21.73. Bar below 8 mm fails the Eurocode 2 ductility note. That note does not make the pack A142. Grade words for loose bar are on the reinforcing steel buying guide.

What A142 is for, and what it does not do

The Concrete Society describes fabric in a ground-supported slab as help with cracks from restraint to shrinkage. If a crack forms, the steel limits how wide it opens. The sheet will not necessarily prevent every crack. In large-area pours, a nominal fabric, commonly A142, is often placed in the lower part of the slab, and small amounts of fabric have traditionally not been counted as load capacity. That is crack control, not a hidden beam. Strip construction is a different emphasis: cover near the surface, including a 50 mm cover. Do not pick one depth for every slab, and do not take a garage or driveway mesh weight from this page. Mesh lying on the membrane does no work. It needs chairs. Cutting a sheet into strips to line a trench does not turn crack-control mesh into designed bar.
Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m

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Just The Job Supplies Just The Job 8 mm bar, 10 × 1 m
9.2/10about £25.20
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When the drawing wants loose bar

Use loose bar when the drawing shows bars, a cage, or a trench a 4.8 m sheet will not sit in. A named fabric sheet is the crack-control choice for an area. Next Day Steel points A142 at a path or shed base. That is a stockist's guide, not a size you copy into a footing. Ten 1 m bars do not become a 4.8 m by 2.4 m grid. The welds and the sheet weight are missing. If the trench is for a lived-in wall, call first. Footing rules stay on reinforcing steel for foundations.

What to refuse

Refuse trolley mesh in a footing. LABC does not advocate it. Refuse D wrapping mesh offered as slab fabric. The Concrete Society's D category is not A142. Refuse a 6 mm loose pack sold as A142. B09PRTY1B2 is bar, at £21.73 for ten metres. A142 is 6 mm wire at 200 mm centres, about 2.22 kg per square metre, in a sheet. Both saying 6 mm is how the products get swapped. If the drawing shows nothing and the slab is a light path, a nominal sheet on chairs is the usual crack-control conversation, not a promise of an uncracked slab. If it shows bars, buy the diameter and the single grade the drawing names. These short packs often cannot support that claim.

Common questions

What is A142 in one sentence?
A142 is a square fabric sheet, 6 mm wires at 200 mm centres, 142 mm² per metre each way and 2.22 kg per square metre on the CARES table from BS 4483:2025, with a stock sheet of 4.8 m by 2.4 m on that table. It is crack-control mesh for slabs, not a loose bar.
Is a pack of 6 mm loose bar the same product as A142?
No. The pack B09PRTY1B2 is ten separate 6 mm bars, 1 m long, at £21.73. A142 is a welded grid at 200 mm pitch. The note about loose bar below 8 mm and Eurocode 2 ductility applies to the bars. It does not turn them into fabric, and it does not condemn the sheet.
Does fabric stop a slab cracking?
The Concrete Society says fabric helps control cracks from restraint to shrinkage, and that it will not necessarily prevent every crack. If a crack forms, the steel limits the opening. Nominal fabric in a large pour has traditionally not been counted as the slab's load capacity. It is not a guarantee of an uncracked floor.
Can you cut a mesh sheet down to line a narrow trench?
You can cut fabric on site, but strips of A142 in a trench are not a designed cage. A142 is crack-control sheet. A footing that needs steel needs the bar or the fabric the design names. LABC rejects trolley mesh for that job as well. Cover and chairs still apply.
What should you refuse if both products are in the same search?
Refuse a 6 mm bar pack described as A142, refuse wrapping mesh described as slab fabric, and refuse trolley grid in a foundation. Choose a named sheet for a designed crack-control slab, and loose bar only when the drawing shows bars. This comparison does not sell the sheet, so it cannot price one for you.

Related pages

How to fix reinforcing steel

Reinforcing steel

Best reinforcing steel bar for a short posted pack

Reinforcing steel buying guide for diameter and grade

Reinforcing steel for foundations and plain strips

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 23 October 2026.

  1. CARES specification guide (retrieved 23 October 2026)
  2. CARES bar mark (retrieved 23 October 2026)
  3. Concrete Centre: European standards for reinforcement (retrieved 23 October 2026)
  4. LABC: reinforcement in foundations (retrieved 23 October 2026)
  5. Concrete Society: cover to concrete cast against the ground (retrieved 23 October 2026)
  6. Concrete Society: reinforcement contamination and rust (retrieved 23 October 2026)
  7. Approved Document A (retrieved 23 October 2026)
  8. Next Day Steel: 10 mm rebar (retrieved 23 October 2026)
  9. The Metal Store: reinforcing bar (retrieved 23 October 2026)
  10. HSENI via NISG: alternatives to grinding (retrieved 23 October 2026)