Preparing Cement Board Walls for Microcement

Watch the video below for a step by step guide to preparing cement boards for microcement down to the floor by Richie from Relentless Microcement.

Cement boards are most commonly used in Bathrooms & Wet Rooms but the same prinicipals apply if you are using microcement on cement boards elsewhere in the house or garden. Richie demonstrates the most important things to be aware of when preparing surfaces for Microcement. Essential watching for anyone who is looking to Microcement cement board walls down to the floor.

Cement Boards are often used in wet rooms on floors and walls. Some common cement board brands include: KNAUF AQUA-PANELS® / NO MORE PLY® / HARDIE® BACKER BOARDS

Well Consolidated
Make sure the boards are well glued and screwed in place to eliminate any chance of movement. If you are fitting the boards yourself, use a suitable adhesive between the joins, leave to dry overnight and razor scrape/sand the excess off once set. Make sure silicone is not left on the surface to be microcemented. Refer to cement board manufacturer for best adhesive products to use. Countersink screw holes.

Completely Flat
Boards must be flush with one another, ridges will highlight in the microcement. There must be no voids, even around the bottom edge. Microcement can’t be used to level surfaces/fill voids – it must only be applied as thinly as the grain. The surface must be completely flat. As with all surfaces, microcement will follow the contours of the substrate it is going onto.

Fill the Joins and Screw holes with MicroDur Base or Suitable Repair Mortar so that they are flush with the boards.

IMPORTANT: Leave until dry, minimum 24 hours. If the MicroDur Base/Mortar isn’t completely dry, the lines & holes may ghost through the microcement and be visible in the finish. Once the MicroDur Base/Mortar is dry, use wide, self adhesive skrim tape to bridge the joins in the corners.

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.

Let us know if you need anything else or have any questions.