Natural Stone Sealant: What You Need To Know

By Cappstone Inc. |
natural stone sealant

There are many things you need to know about natural stone sealant if you’ve just invested in some natural stone for your countertops, flooring, fireplace, bathrooms walls, or elsewhere. It’s not just a matter of whether or not you should seal your natural stone, unfortunately. The good thing is that your choosing natural stone means you have a beautiful and durable taste.

There’s only bad news if you don’t do your homework on it! If you choose the wrong sealant, or worse, if you ignore the need to seal your natural stone, you risk exposing it to damage and inevitably shorten its lifespan. Don’t be discouraged by the extra work, let us help! Here’s what you need to know about natural stone sealant:

How to Know if You Need Sealant

For the most part, it’s a good idea to apply sealant to your natural stone. This helps keep it looking gorgeous and protects it from wear and tear, extending its life. The need for sealant, specifically, which kind, how much of it, and how often you’ll need to reapply, is determined by the porousness of your natural stone. One way to determine this is to conduct an absorbency test. Simply drop a few drops of water on your natural stone and time how long it takes for the drops to disappear. The quicker it disappears, the more porous your stone. The more porous, the more sealant that needs to be applied, and more often, too.

Types of Sealant

There are two major categories of natural stone sealants. These are coating sealants and impregnators, or penetrating sealants. Coating sealants, as suggested by their name, create a coating on top of the stone which serves as a barrier that prevents things like water, oil, and dirt from entering the pores of the stone. Impregnating sealant penetrates into the stone, depositing solid particles in the pores of the stone to coat its minerals and restrict water, oil, and dirt from entering the stone. 

Choosing the Correct Sealant

Industry experts list several factors to consider when choosing the right sealant for your natural stone, including the stone type, stone finish, stone location, and the stone’s current or intended maintenance methods. For example, limestone floors in a high-traffic walkway will need different sealant than granite countertops.

How to Apply Sealant

Different sealants require unique application methods on each different type of natural stone, however similar the stones may be and simple the sealant application process is. Luckily, the Natural Stone Institute provides great resources for everything natural stone, including a detailed guide on sealant installation.

In it, the NSI lists five basic steps for preparing to seal natural stone. These are: 

  • Cleaning, drying, and dusting joint surfaces
  • Applying primer (if required) to cleaned surfaces
  • Applying bond breaker (if required)
  • Applying sealant to joint cavities
  • Using dry tooling techniques to ensure sealant has proper configuration and full contact on joint walls
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