Sealing Granite and Marble - Learn How!
To seal or not to seal?
This is the most common question asked by natural stone owners. If you ask several people whether you should seal your granite & marble, you'll get different answers. However, there is a good reason for these differing opinions: not all stone need to be sealed!
Check out this simple sealing guide plus tips and tricks to keep your countertops in pristine condition.
What does sealant do?
Using a sealer on your natural stone will help protect it from stains while also giving you some extra time to clean up any spills on the surface. It’s worth noting that while sealants provide an extra barrier to your stone, daily wear and tear can still often cause it to etch. To avoid excessive etching, we recommend wiping spills as soon as possible and using trivets and cutting boards when cooking and preparing meals.
Water drop test
The simple water drop test is one of the easiest ways to check if your natural stone needs sealing! Start by sprinkling a tablespoon of water on the stone. Let the water sit on the surface for about 15 minutes. If the stone turns black or water is absorbed in less than 4 minutes, it will need to be resealed. This experiment can be done every few months to check the quality of the stone.
Types of sealants
The type of sealant you use depends on the surface you want it to be applied to. Different gemstones require different treatments, so know yours! Ideally, you want the sealant to be heat-resistant and unaffected by household substances. There are two main sealers: topical and impregnators.
Topical Sealers
Topical sealers are coatings that will protect the surface area of the stone. This coating will guard against oil, water and other debris. They are cost-effective, easy to apply, and are slip resistant. However, low-quality coatings can discolor stone, and reapplying can often require harsh stripping.
Impregnators
Impregnators are water-based sealers that penetrate the surface of the stone. Although this solvent acts as a repellent against anti-stone substances, it still allows the surface to “breathe.” The majority of impregnators won’t change the stone’s appearance, are long-lasting and are not affected by UV lighting. However it’s generally not as cost-effective, and the application process can be more difficult.
Sealing Properties
Marble
Impregnants, acid-resistant and food-safe sealants are best for sealing marble. Many people believe that etching is a sign of resealing, but this is a myth. Etching occurs when acid is absorbed into marble’s characteristic calcium-containing surface. Try using an acid-free cleaner when caring for marble.
Granite
The best options for sealing granite are waterproofing agents, food-safe sealants, and aliphatic fluorocarbon resins. Due to the density of granite, solvents and resins must be lightweight. Avoid linseed, silicone and silicone resins as they will ruin your stone!
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How to seal?
1. Clean the stone deeply.
Clean the surface before applying sealant to ensure a more even application. Make sure to remove any unwanted stains, as stains will stick once sealed – which is obviously what you want to avoid. If you’re having trouble with stains, the Natural Stone Institute has a detailed list of stains and how to remove them! To wipe the surface, use a pH-neutral cleaner and a lint-free cloth. Then make sure the stone is completely dry before proceeding to the next step.
2. Wear gloves and ventilate the area.
Most sealants are harmless, but safety precautions always need to be taken. Wear gloves to protect yourself from harmful chemicals. Also, to avoid strong odors, open windows or turn on a fan to ventilate the area where you are working.
3. Test the product on a small scale.
Always test your product before tackling the entire project. This is to ensure that the sealant is compatible with the stone. If the sealer leaves a cloudy residue or causes discoloration, use a different product.
4: Apply sealant with a soft brush or sprayer.
Always follow the manufacturer’s application instructions. Depending on whether the stone has been polished, honed, or fired, the manufacturer may require specific techniques or amounts of sealing. Protect any surfaces that don’t require sealant (such as faucets, sinks, stoves, or walls). You can wrap the device with plastic wrap; placing a magazine cover between the wall and the stone will suffice. Please follow the manufacturer’s instructions for “Cure Time” as this may vary from product to product.
5. Remove the excess sealant.
The stone will absorb some sealer, but some excess sealant will usually remain on the surface. Use a microfiber cloth to absorb excess. You should avoid letting leftover sealant dry on the counter as this may cause discoloration.
6. Apply additional coats (as needed).
Applying additional coats is normal. Usually recommended for best coverage. We believe it never hurts to be thorough! The more porous the stone is, the more likely it is that additional sealant will be needed. A general rule of thumb is to wait 15-30 minutes between coats.
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