Preparing Painted, Plastered or Plasterboarded Walls for Microcement
You can microcement onto painted, plastered and plaster boarded walls. Because plaster is completely flat, it is a lot easier to microcement onto. Plasterboard will need some additional prep.
Sand the paint with 120 grit sand paper to remove any loose paint and give it a key.
Ideally use tapered edge plasterboards. Ensure the boards are well glued and screwed in place. Tape the joins and flush with a compatible filling and finishing compound or MicroDur Base. IMPORTANT: Leave until dry, minimum 24 hours. If it isn’t completely dry, the lines may ghost through the microcement and be visible in the finish.
There must be no voids between adjacent walls or the wall & floor. If you are fitting the boards yourself, use an adhesive sealant along the bottom edge of the boards and squash the boards down to the shower tray/floor. Don’t smear sealant/silicone on the surface, instead, let it ooze out and razor scrape off the excess once it is dry. Use wide, self adhesive skrim tape to bridge the internal corner.
All boards must be well glued and screwed in place. so that any chance of movement has been eliminated.