SEALER SERIES Part 1: The Different Choices

By Chris Sullivan – ChemSystems, Inc.

Sealers, and the problems associated with them, continue to be the biggest source of frustration for decorative concrete applicators around the country. It's easy to understand why: There are a vast number of sealer products on the market for decorative concrete, yet many contractors lack a basic understanding of how to select and properly apply the products. This series of blog articles will address the most common sealer problems encountered in the field, why they occur, and how to avoid and repair them.

Before we can get into dealing with problems, it's necessary to give you some background on the products being used. I am continually amazed at how many applicators I talk to that know very little about the sealer they have been using for years (other than the color of the can it comes). While most sealers straight out of the container look, smell and flow similarly, there are major differences. Here's brief overview of the four types of sealer products used for decorative concrete. All have a different function, purpose and recommended method of application.

Cures are designed to slow initial hydration of concrete to create a stronger product and minimize shrinkage cracking. However, they are not intended to provide long-term durability and protection. They are applied as soon as the freshly placed concrete can be walked on, and they can be tinted to match colored concrete.

Sealers provide long-term protection and color enhancement. But they should not be applied until after concrete has cured. The recommended minimum curing time is 28 days, but most contractors typically wait only 7 to 14 days. View this comparison chart of concrete sealers.

Cure and seals, as you might expect, blend some of the benefits of cures and sealers. Like cures, they slow initial hydration of concrete to create a stronger product and minimize shrinkage cracking. They also provide mid-term protection of 6 to 12 months. These products are applied as soon as the concrete can be walked on.

Coatings provide long-term protection, the best chemical resistance, and color enhancement. Like sealers, they must be applied after the concrete has fully cured (28 days). They may also require special surface preparation for proper adhesion.

Note that cures, cure and seals, and straight sealers all have a dry film thickness of about 1 mil and are breathable. Coatings are thicker (2 to 3 mils) and typically nonbreathable. Even with so many options and chemistries, the problems I see with these products, such as environmental impact and application issues, are similar no matter what product is used.

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