Waterproofing Membrane tips | Importance of Primer in Waterproofing Systems

Applying waterproofing primer with brush

The purpose of waterproofing primer is to ensure the surface is fully sealed and prepared to apply waterproofing membrane. It also provides bonding strength between the substrate with waterproofing membrane. Waterproofing primers usually used on porous surfaces, and additionally strengthen the surface.

Failure to prime the areas before preparing for the application of waterproofing membrane is the second most repeated problem in waterproofing failure. This is due to the waterproofing membrane unable to bond to the substrates.

Each manufacturer for waterproofing membrane would suggest priming on surfaces before applying. There are various primers available for different kind of substrate and surfaces.

How to apply waterproofing Primer?

Recommend to always use primers that are specified by manufacturers especially for surface priming for CFC, mortar, concrete, mortar screeds and plywood substrates. Priming the surfaces will decrease porosity, air-entrapment (pin hole), dusting and high residual moisture in surfaces where it could potentially cause blistering on the waterproofing membrane after curing.


However, not all primers are the same. For example, one-part solvent or water based primer such as Primer-W are usually used to cover the substrate and increase adhesion of the waterproofing membrane. Two-part water based epoxies work in similar method but can also use to seal off high residual moisture in the surface.  

Contractor sweeping the substrate to clean it before applying waterproofing

Need more information and waterproofing advise of Primer for your projects?

If you would like any further information about primers, please contact us or send us an email to info@chemind.com.my . Our friendly team of waterproofing specialists pride themselves on providing great service and will be delighted to help.

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