How to Install Mesh in a Concrete Slab

✔ How to Install Mesh in a Slab

1. 1

   Prepare and Level the Sub-Base

   Before any mesh goes in, make sure your sub-base is properly compacted and level. Use MOT Type 1 or a similar compactable material, laid in layers and compacted thoroughly using a plate compactor. The surface should be firm, even, and solid underfoot. If required, lay down a damp-proof membrane (DPM) over the compacted base before mesh installation. This will protect the slab from rising damp and help preserve the concrete’s integrity long-term. The better your ground prep, the easier it will be to place your mesh and keep it at the correct height throughout the pour.

2. 2

   Lay Mesh on Spacers or Chairs

   Mesh reinforcement must sit within the top third of the slab to do its job properly. Never lay it flat on the base or DPM. Use mesh spacers, known as “chairs,” to lift the mesh roughly 40–50mm off the ground depending on the slab thickness. This ensures the mesh stays suspended in the concrete and helps control cracking. Spacers should be placed every metre or so across the grid. For deeper slabs or high-load areas like driveways, consider double-layer mesh or using higher chairs. Getting this height right is crucial — it’s what makes the mesh effective, not just present.

3. 3

   Tie and Overlap the Mesh Sheets

   Where two mesh sheets meet, they should overlap by at least 200mm (two squares) in each direction. Use steel tying wire or cable ties to secure them together tightly at the overlap points. This prevents the mesh from shifting during the pour and ensures the reinforcement acts as one continuous unit. Go around the edges and corners to check everything is tied down properly. Avoid leaving any loose edges sticking up — they can catch during pouring and get pulled out of place. If using cut mesh near formwork or awkward corners, make sure the cut sections are also properly supported and tied into the main grid.

4. 4

   Pour the Concrete Carefully Over the Mesh

   Once the mesh is positioned and tied, you’re ready to pour. Start pouring concrete evenly across the slab, taking care not to drag the mesh out of position with tools or foot traffic. If possible, work from one side and use a screed board across the top of the formwork to level the surface as you go. Watch that the mesh stays suspended during pouring — it should remain inside the upper third of the slab, not sink to the base. In deeper slabs or larger pours, have a second person spot and adjust the mesh during the process if needed. Once poured, float and finish as usual.

5. 5

   Let It Cure Without Disturbance

   After pouring and finishing, protect the slab while it cures. Avoid walking on it for at least 24–48 hours and don’t drive or place heavy loads on it for a full 7 days (or longer, depending on the mix). Curing is just as important as pouring — it’s when the concrete gains strength and the mesh does its job inside the slab. Use a curing compound, plastic sheeting, or hessian blankets if the weather is hot, dry, or windy. This will prevent rapid moisture loss and help reduce shrinkage cracking. Patience here makes all the difference in long-term performance.