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Bond coating for limestone : what are the benefits ?

FAQs , Laying & fixing

What is a bond coating and what is its purpose ? First and foremost, a bond coating is a film-forming interposition product designed to prepare a surface before it is covered with mortar (for example a white glue).

There are 5 main reasons for using a bonding primer or adhesion primer.

1/ Regulate the porosity of the absorbent substrate via the bond coating

A porous substrate can absorb the water contained in the mortar applied to its surface (such as a leveling compound, tile adhesive, etc.). This phenomenon can lead to pathologies like powdered or blistered leveling compound, for example.

An appropriate bond coating is used to regulate the porosity of the substrate and minimize water absorption, aiming for a uniform finish.

2/ Creating a bond bridge with bond coating

On non-porous, smooth, or closed surfaces, an appropriate bond coating will promote the adhesion of self-leveling compound or tile adhesive. This is referred to as an adhesion bridge.

3/ Facilitate the application of self-leveling compound or adhesive.

Applying a bond coating evens out the surface and, for porous substrates, regulates porosity. When used on floors, it makes it easier to apply and spread self-leveling compound.

4/ Separating two chemically incompatible layers.

A cement-based tile adhesive, for example, is incompatible with an anhydrite screed. Therefore, this adhesive cannot be applied directly to this surface. In this case, a bond coating will be used to act as an interposing layer, separating the adhesive from the screed.

5/ To limit moisture rising on the stone.

On supports directly on ground level, there can be issues with moisture rising. A specific bond caoting can be used to block these moisture rises that may affect the floor covering.

Note : We advise against applying bond coating outdoors.