What a slab needs to do
A concrete slab spreads load across the ground beneath it. Whether it's a garage base, workshop floor, extension floor or hardstanding, the slab needs the right thickness, sub-base and reinforcement for the load it will carry.
A domestic garage floor at 100–150mm on MOT Type 1 is standard. A commercial slab taking HGV traffic needs to be thicker — 150–200mm — with heavier reinforcement.
Sub-base and reinforcement
Lay MOT Type 1 at 100–150mm, compacted in layers. Place steel mesh on chairs so it sits in the middle of the slab. Without chairs, the mesh ends up on the sub-base and does nothing.
For larger slabs, fibres can replace or supplement mesh. They control shrinkage cracking and are easier to place.
Curing and joints
Concrete needs to cure slowly to reach full strength. Cover it with plastic sheeting or use a curing spray to prevent rapid surface drying — especially in wind or sun. Rapid drying causes surface cracking.
Cut control joints into the slab as it begins to harden, at roughly 3m intervals, so any cracking follows the joints rather than running randomly across the surface.
Agricultural and commercial slabs
Agricultural slabs for livestock, machinery or grain stores need a stronger mix (C35) and may need fibres or mesh. Commercial slabs for yards and loading areas need to withstand point loads and chemical spillage.
Tell us what the slab is for and we'll batch the right mix on site.
Related services
Need concrete for your project? We supply volumetric concrete across South Wales, mixed fresh on site to the exact quantity you need. Request a quote or call 01495 820164.