Rockcote’s Anti Efflorescent Primer has excellent adhesion and will also provide a slip resistant finish for easy application of subsequent trowel applied coatings or paint. It is specifically formulated to provide an effective barrier coat against efflorescence. It should be used for the priming of all site-mixed renders and mortar-joined brick or block walls.
Efflorescence is caused by the migration of salts in moisture through a wall or substrate. It is a crystalline deposit that can appear on some substrates, and is normally whitish in colour. Efflorescence can present as a cosmetic problem, but can sometimes also indicate an internal structural weakness in masonry substrates, and/or an issue with moisture ingress.
Rockcote renders are formulated so that salts are not present, and so that moisture migration is restricted. Both of these actions prevent efflorescence occurring in Rockcote renders.
Rockcote Anti Efflorescent Primer should be applied to the brick or block substrate as the first coat before subsequent coats are applied. This is also the case when applying any finish over an existing substrate that has a site mix render, as efflorescence could still seep through to the surface. Rockcote’s Anti Efflorescent Primer therefore, should be applied as the first coat for all systems over site mix render, and on painted or bagged finishes over mortar-joined brick or block walls.