1Concrete Mix & Materials
32 MPa mix minimum, go higher for nil/minimal exposure.
Mesh: double 82, 92 or 101.
Tell your supplier it's for a polished finish, they must use fresh clean water, not recycled water, which causes brown discolouration that shows in the finished floor.
2Pouring the Slab
Place concrete to achieve the most even aggregate exposure.
New loads placed 500 mm minimum over screeded edges.
Vibrate vertically, not dragged horizontally, at centres that let air escape.
Fill screeders' footprints with fresh concrete, not screed cream.
Don't rest idle screeds or trowelling machines on wet concrete for more than 5 minutes, they leave impressions and push aggregate down.
Use laser levels throughout, even after each metre of screeding, to keep it flat and level.
Avoid pouring on a very hot day, it encourages surface shrinkage and cracking.
3Finishing
Trowel and compact to a flat surface with minimal-to-no undulations.
Cross-cut the slab (trowel one way, then back the other) to avoid lumping and high spots.
"Class A" finish, no more than 3 mm deviation over a 3 m straight edge.
Final texture: broom for full exposure, or leave machine-smooth for nil/minimal exposure.
4Curing
Fully vibrate and plastic-cure. Cover with hessian or a water-based curing compound (e.g. Multicure R) immediately after finishing. Curing requirements vary by exposure level.
Keep covered/cured a minimum 14 days, or until OzGrind can begin grinding (unless a curing compound is used).
Slab must cure a minimum 28 days. Call the office to discuss if this needs to be negotiated.
Waffle-pod slabs: avoid where possible. If you must use one, take extra care moving across the waffles so the mesh and chairs aren't pushed up toward the surface, this can cause cracking and imperfections.
