Oct 4th 2018 / General Stone Care
What is the best sealer to use on natural stone?
To seal or not to seal? That is the question...
Not all natural stones are treated the same. Did you know not all stones need to be sealed? Did you know that many darker granites do not need to be sealed at all? Each stone has its own characteristics and with our tips you can easily figure out if your stone needs to be sealed.
Have you been told you have to seal your stone every six months? Have you spent so many hours googling "sealers for stone" only to find many different sealers and suggestions on how to seal that you are more confused than before your search? We get these phone calls everyday and we are here to help! No matter what type of stone you have or when it was last sealed- start with figuring out if your stone actually needs to be sealed. You can do this by performing the water test. The water test will let you know if you need to seal- or not.
Pour a palm sized amount of water on the stone and let dwell for 20-30 minutes. If the stone underneath turns darker you know you will need to seal. If the stone does not change color, sealing is not needed at this time.
**the water will not leave a permanent mark; once the stone dries the dark spot will go away.
What does the water test tell you?
If the stone underneath the water turns darker- this means the stone is porous and is absorbing water. If the stone is absorbing water, it will absorb other substances such as oil and grease as well. You will want to seal the stone at this time. Some stones are more porous than others such as limestone and travertine. These stones might need multiple applications to ensure the pits or pores are adequately sealed to prevent staining.
*tip- lighter stones (any stone) are more porous than darker stones so these should be tested periodically to make sure the sealer is still working.
How do sealers work?
Many people do not know that sealers do not sit on top of the stone, but rather sit below the surface to fill up the microscopic pores in the stone. Lighter stones are more porous than darker stones and will most likely need to be sealed. Dark granites do not always need to be sealed as they are not usually porous. Each stone is different so we always recommend performing the water test regardless of the color or type of stone (better to be safe than sorry).
If the water test shows that a dark granite is not absorbing water- DO NOT SEAL. If the sealer is not being absorbed into the stone, there is no where for it to go. Most of the time what happens in this instance is that the sealer sits on top of the stone and creates a type of plastic coating. This (over time) will cause the stone to look dull. This is because the "plastic coating" is starting to etch and wear away. If you have a dark granite (such as absolute black) that has been sealed, we recommend removing the sealer. You can do this by using denatured alcohol from your local hardware store. Wipe the alcohol on the stone and let sit for about 20 minutes then wipe dry.
Sealers do not prevent etching
Sealers will not prevent etching- only staining. An etch mark is a chemical reaction that affect calcite based stones such as marble, travertine and limestone (an etch is always lighter than the stone whereas a stain is always darker than the stone). There are no DIY products that will prevent etching on calcite based stones, but there are some products a Stone Restoration Professional can apply (coatings) to help prevent etching. You can call your local Stone Pro to see if they offer this type of service- many do.
Below are a list of the sealers we currently offer. Please feel free to contact us anytime should you have any questions regarding your stone.
MB-24 "Barrier" is a water-based Professional grade fluorochemical sealer that is extremely user friendly for homeowner and pro alike. Easy to apply to small or large areas; floors, counter tops and any surface that requires sealing. It will provide a durable, non-film forming, transparent, protective barrier against oil and water on porous surfaces such as marble, limestone, travertine, granite, slate, unglazed tile, grout, terracotta, concrete and brick. Barrier provides excellent oil and water repellency, stain resistance, and easy stain cleanup.
MB-21 Enhance Color Enhancing Sealer is a Professional grade premium solvent based, VOC compliant formulation. MB-21 Enhance is an easy to use, clear, very low odor, non-flammable formulation that was designed for homeowners and contractors alike. MB-21 Enhance is safe to use on food prep surfaces and not sensitive to most common household acidic substances. The result is permanent. MB-21 Enhance provides optimum sealing capabilities protecting against oil and water based staining agents. It will enhance the color (darken) of tumbled marble, unpolished limestone and any other non-polished (honed, cleft, flamed, etc.) stone surface including brick, concrete, and terracotta. Coverage area: 100-200 sq ft per quart bottle, depending on the stone.