Preparing Painted and Plastered Walls for Microcement
If you’re installing microcement onto a plastered or painted wall, then a lot of the work will have been done for you already.
The wall should be completely smooth and free from any movement before you apply microcement.
Make sure the wall is completely dry (maximum moisture content 5%).
If the wall has been painted, then make sure there is no loose or flaking paint left on the surface.
For freshly plastered walls, you’ll need to apply a diluted coat of Primer 100 at a ratio of 50:50 with water, followed by a neat coat of Primer 100.
Whilst microcement is very strong, smooth & flexible, it relies entirely on the surface (aka substrate) that it’s going onto to be completely smooth and free from movement.
The surface must be flushed out and the chance of movement eliminated before microcement is applied.
Golden Rules:
- Surfaces should be completely smooth – as if you were going to paint onto them.
- Surfaces should be well consolidated, so that any chance of movement is eliminated.
Additional Important Rules:
- Never Microcement directly onto natural timber or across cold joints/expansion joints.
- Surfaces should be free from oil stains, dirt, dust and excessive laintance.
- Surfaces must be fully cured with a moisture content of no more than 5%.
- Microcement can only be applied to surfaces with a compressive strength of at least 16N/mm2.
- There must be no risk of water getting to the microcement during the install process.
- Surfaces must be damp-proofed so that no water can get to the Microcement from underneath at anytime.
- Allow 3-4mm as the finished depth.