Q.  I read online that a primer is recommended before applying a sealer. Why do I need a primer and which primer should I use?

Published Thursday 21st of June 2018 // Updated Tuesday 29th of May 2018

A. We highly recommend applying a densifying primer before using a sealer. Concrete densifiers are penetrating, chemically reactive products. They react with calcium hydroxide, a byproduct of cement hydration, to create C-S-H (calcium-silicate-hydrate). (The same binder that results from adding water to cement and gives concrete much of its strength). The newly created C-S-H fills in the pores and capillaries of the concrete making it up to 50% stronger. By filling these voids with C-S-H, the concrete also becomes less porous and less permeable.

When choosing a densifying primer we recommend the Lithi-Tek 4500 which is a concentrated, non-water-soluble, lithium silicate based product. Lithi-Tek 4500 is economical and only needs to be applied once in the lifetime of the concrete. Since densifiers like the Lithi-Tek 4500 are not hydrophobic or salt resistant a penetrating, impregnating sealer is recommended 5-7 days after priming. This combination will ensure a stronger and water salt & stain resistant surface for years to come.

shield-bullet Tip: Densifying primers are only recommended for concrete (not: brick, pavers, stamped concrete, colored concrete, etc.)

Sila-Tek 3500

Densifier & hardener

Lithi-Tek 4500

Densifier & hardener

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