Learn how to choose the right primer and when it has be applied in flooring works
The role of primers
Primers provide the base for the installation. They bind the dust, increase or create adhesion “bonding-bridge”, create uniform absorbency of the substrate and protect the substrate against moisture of levelling compounds.
- Additional benefits of some primers: they seals residual moisture and reinforce the substrate.
Recommended relative air humidity content is below 75%. The higher humidity content the slower SLC drying proces. Optimal conditions for SLC application and usually taken as reference conditions are: air temperature +23°C and air humidity 50%.
Different primers for different substrates
Depending on a kind of substrate, you should use a proper primer.
- On absorbent and highly absorbent substrates: apply penetration primers – sometimes a few applications are necessary.
- On non-absorbent substrates: apply a film forming primer – as thick as necessary to build a uniform film.
Get the right rimer
Depending on a kind of substrate and special purposes, choose a proper primer:
- For absorbent screeds and concrete floors use dispersion water-based primer Ceresit R 777 or the universal one – Ceresit CT 17.
- For absorbent, impervious, dusting and unstable surfaces use PU primer Ceresit R 740.
- Against rising moisture and for surfaces exposed to mechanical and chemical stresses use epoxy primer Ceresit R 755.
- For universal purposes use a multi-purpose primer Ceresit R 766 or a universal primer Ceresit CT 19.
- For difficult substrates (PVC, tile-on-tile, chipboard etc.) use special primer Ceresit CT 19 or Ceresit CN 94.
How to strengthen substrate and improve adhesion
Special natural wetting agents provide better coverage and good adhesion on the critical substrate. These liquid softening wetting agents are plasticizing and tackifying resin. Combination of selected dispersions provides durability, flexibility and adhesion. Particles of different sizes help polymers to penetrate even difficult types of surface, resulting in better overall flexibility. Ceresit CN 94 strengthens the substrate surface and improves adhesion.