Preparing Internal and External Corners for Microcement
To get nice tidy corners with the microcement, it’s essential that the prep work is done right, surfaces need to be completely flat & free from movement.
This guide demonstrates how to prepare internal and external corners, with this is mind.
Eliminate Movement
Ensure that the surfaces are well glued & screwed in place so that movement has been eliminated. Countersink screws, so that they don’t stick out passed the surface.
Completely Flat
Both surfaces must be completely flat, with no voids, before the microcement is applied.
There must be no voids between the two adjacent surfaces. Any large voids will need to be filled with a suitable filler or over boarded.
Joint Filler can be used to fill the joins between boards and screw holes, up to around 10mm. Or you can use a filler that is suitable for the surface that you are applying it to.
For internal corners, start in the corner & trowel away from it, to avoid the filler building up in the corner, which is difficult to sand. Feather the filler across each of the surfaces to ensure a flat surface.
Leave Filler to Dry, then Sand
Leave the filler until it is fully dry (no more than 5% moisture content), then sand both sides of the corner until the surfaces are completely flat. Keep the sander flat on either side to get a clean corner.
To get right into the internal corner, fold some sand paper in half & use it to sand into the corner by hand.
Strengthen with Fibreglass Mesh for Corners
Once the surface is nice & flat, strengthen the corner with Fibreglass Mesh for Corners. Squash the tape right into the corner, so there is no loose tape in the corner.
No Need for Angle Beads
You don’t need to use angle beads, as the microcement is a lot stronger than plaster & you need the surface to be completely flat.
Follow this guide if angle beads have already been installed:
Using Angle Beads, Stop Beads and Expansion Beads with Microcement