Laying a Ready Polished Floor
Preparation is the key to any successful concrete floor. Ensure your concrete placer is aware that they are laying a Ready Polished floor so they can take the following precautions.
Reduce the risk of uncontrolled cracking
- Wrap all protrusions such as drain pipes with a compressible foam (needs only to be 5mm thick) to stop the slab hanging up on it.
- Locate some substantial trimmer bars with some washer plates at each end, hard up against all re-entrant corners. Placing them away from the corner enables the crack to initiate (bad). The risks of associated loss of cover are less than the risk of uncontrolled cracking.
- Get the under-slab area smooth and flat. Consider 2 layers of polythene to reduce friction between the ground and the slab.
- Concrete block footings (web intrusions) could cause additional edge restraint and lead to uncontrolled cracking. In critical situations consider high quality timber forms instead to lower the edge restraint risk.
- Adjust the floor footprint where ever possible to accommodate the saw cutting plan. Locate the joints under walls where ever possible.
- Try to eliminate any additional restraint due to ground beams and consider how the concrete will try and move as it expands and contracts with heat. Consider propriety doweling systems instead of conventional reinforcing ties. This design may require specific input form a structural engineer.
- Consideration must be given to cutting. Saw cuts must be done as soon as concrete can be walked on and within 24 hours of the concrete being poured. The cuts must be at least 1/4 to 1/3 of the overall slab thickness to be effective.
- The use of underfloor heating can significantly increase the risk of plastic cracking and precautions should be taken to reduce
this risk.
Over Vibration
Over-vibration can effect a floor causing aggregate to sink to the bottom leaving noticeable imperfections in the overall finish.
Care must be taken when placing your Ready Polished floor. Concrete is the only material that arrives on site in its unfinished state. This means that its final appearance will be influenced by site conditions and workmanship. Variations in surface colour, texture and consistence in surface composition are inevitable.
