Reinforcing mesh is an important part of many concrete slabs. Correctly specified and positioned, it helps the slab distribute stresses and control cracking. It does not make concrete crack-proof, and it cannot compensate for poor ground preparation, incorrect slab thickness, missing joints or unsuitable concrete.
Important: This article is a general guide only. The mesh grade, slab thickness, reinforcement layout, concrete cover, laps, footings and joints must follow the engineer’s design, approved plans and project specification. If you are unsure, ask your engineer or building professional before ordering or placing reinforcement.
What do SL62, SL72, SL82 and SL92 mean?
SL mesh is welded square reinforcing mesh made from ribbed steel wires. In the common grades below, the wires run at 200 mm centres in both directions. As the grade number increases, the wire diameter and sheet weight increase—but a heavier grade is not automatically the correct choice for every slab.
| Mesh grade | Main wire diameter | Wire spacing | Approx. sheet weight | Effective sheet size |
|---|---|---|---|---|
| SL62 | 6.0 mm | 200 mm | 33 kg | 5.8 × 2.4 m |
| SL72 | 6.75 mm | 200 mm | 41 kg | 5.8 × 2.4 m |
| SL82 | 7.6 mm | 200 mm | 52 kg | 5.8 × 2.4 m |
| SL92 | 8.6 mm | 200 mm | 66 kg | 5.8 × 2.4 m |
Our Class L Ribbed Square Reinforcing Mesh is made from 500 MPa welded ribbed wire and is available in SL62, SL72, SL82, SL92 and additional grades. The correct selection depends on the engineer’s design, anticipated loads, ground conditions, slab dimensions, thickness and joint layout—not simply whether the job is called a path, driveway or shed.
Be cautious with unusually cheap reinforcing mesh
A low price does not automatically mean reinforcing mesh is poor quality, and imported mesh can meet Australian requirements. The concern is unusually cheap or unverified material that cannot demonstrate the specified grade, strength, dimensions, wire diameter, spacing and weld quality.
Before buying, check that the mesh is clearly identified and that the supplier can provide evidence of compliance with AS/NZS 4671 and appropriate product traceability. Confirm that the grade, wire size, spacing and effective sheet dimensions match the plans especially if a product is being offered as a cheaper substitute.
Reinforcement becomes embedded permanently in the slab. A small saving on unverified mesh is not worth the risk of failed inspection, non-compliant work or reinforcement that does not perform as the design requires.
At Gippsland Concreting Supplies, we stock only high quality reinforcing products not cheap, unverified mesh imports so you can buy with confidence and get the job done properly.
Why mesh position matters
Mesh cannot perform as designed if it is left lying on the sub-base or vapour barrier. It needs to be supported at the height and concrete cover shown on the plans, and it must remain there while concrete is placed. Pulling mesh up by hand during the pour is unreliable because it can settle or move again.
Plastic bar chairs support reinforcing mesh and bar before and during the pour. Our clip-on chairs are available in 25/40 mm, 50/65 mm and 75/90 mm sizes. Choose the chair height and spacing required by the project documents and the reinforcement layout.
Lapping and tying sheets
Adjacent mesh sheets usually need to overlap so reinforcement remains continuous across the slab. There is no single lap measurement that is correct for every project, so follow the engineer’s details or approved plans. Tie the sheets securely enough to maintain the specified lap and position while workers move around and concrete is placed.
Black annealed tie wire is a practical choice for securing reinforcing mesh and bar. For projects with a large number of ties, the Rapidtool Wraptor 18V rebar tier can speed up repetitive tying work across a 12–44 mm tie range.
Square mesh, trench mesh and reinforcing bar
These reinforcement products serve different purposes:
- Square mesh covers broad slab areas and may be specified for paths, patios, driveways, shed floors, house slabs and other concrete work.
- Trench mesh comes in narrow 6 m strips for footings, beams and similar applications where shown on the plans.
- Class N 500N deformed reinforcing bar may be specified for beams, footings, edges, cages and other structural details.
Do not substitute one type or grade for another without approval from the project engineer or designer.
Common reinforcement mistakes to avoid
- Choosing mesh by price or guesswork instead of following the plans.
- Leaving mesh directly on the ground, sub-base or vapour barrier.
- Using the wrong bar-chair height or insufficient support.
- Guessing lap dimensions or allowing sheets to move during the pour.
- Cutting reinforcement around penetrations without checking the design details.
- Assuming reinforcement will prevent every crack.
- Forgetting to coordinate reinforcement with planned joints, thickenings, beams and services.
Plan for safe handling
Full sheets are large, sharp and heavy. The common grades in the table above weigh approximately 33–66 kg per sheet, with some other grades heavier again. Plan unloading and movement before delivery, use suitable mechanical assistance or a team lift where appropriate, wear gloves and other required PPE, keep people clear of unstable sheets, and secure the load correctly for transport.
Get the reinforcement system ready before the pour
Check the latest plans, calculate the required sheets and laps, and have the correct chairs, tie wire and reinforcing bar ready before concrete arrives. Gippsland Concreting Supplies stocks square reinforcing mesh, trench mesh, bar chairs, tie wire and 500N reinforcing bar and RedEdge LVL formwork edgeboards to help you prepare the reinforcement shown on your project documents.
