Sealers for stone (also known as impregnators) are below-surface penetrating sealers, not topical hard shell sealers like those, for instance, that are applied onto wood floors or furniture. They are delivered inside the stone by natural absorption.
Seal Granite The Right Way
15 Years and no need to reapply
Some stones absorb more than others. Granite sealer consists of a solid part, or resin, and a solvent or water carrier.
The solid stays in the stone and clogs the pores of the stone to keep liquid stains out. The carrier brings the solid into the stone and then evaporates.
One of the most important phases of the whole sealing process, is the thorough and complete cleaning and removal of any residue from the stone surface. This prevents any alterations to the color or the finish of the stone surface.
Why should you seal granite? Sealing granite is such a misunderstood practice and misused marketing weapon. It's the result of ignorance in the stone industry and malicious intent by sales people of competing countertop materials.
It's generally believed that when a material is delicate and hard to maintain, it needs to be sealed. The stone industry set out to solve the concerns of staining granite countertops by soliciting chemists to find a sealer for stone. Unfortunately, the chemists didn't know the first thing about petrography.
Granite sealer, the miracle in a bottle, became what I consider one of the most over-promoted, overrated, and over-applied products in history.
See GraniteCarePro.com for professional sealing and cleaning products and how to seal granite.
It should be pretty clear that to work, an impregnator must go into the stone. But to do that, it has to be absorbed by it. Several commercial granites don't absorb anything due to their inherent density. Therefore no impregnator will ever go in.
If you apply it anyway, there's the distinct chance that some of it will remain on the surface of the stone and it will be affected by spills, giving the impression that the stone is damaged.
This damage will appear in the form of "ghost water stains" or "water rings" confused for granite water stains. Some of the best stone surfaces available can be made to look "stained" by sealing them. When in fact, the sealer is what is stained. Do not seal granite counter top stone that does not need it. See Granite Stain Removal for more on this.
You can test your stone to see if it needs sealer by putting a few drops of lemon juice in an inconspicuous place. If dark spots appear quickly, the stone is potentially a problem since it is reacting with an acid. Chances are it cannot be sealed properly. This is what happens with limestone counters. If the drops take a minute or so to be absorbed, you can protect the top with quality sealer.
If the lemon juice doesn't absorb at all, the stone does not need to be sealed. Contrary to what you may have heard, sealing granite is not always a necessary part of granite counter care. In fact, the performance of various granites can differ greatly. Some need sealer to prevent a granite stain while others don't.
Many granite companies use poor quality silicon or siloxane based sealers that require re-application every 6 months or every year. These sealers are very common and many misconceptions about sealing granite come from widespread use of them.
We recommend and use a fluorocarbon alphatic resin sealer. Unlike silicon sealers, it will not evaporate or go through any type of natural deterioration. That is why the particular brand we use for all our sealing, MB Stone MB-4 impregnator, comes with a 10 year warranty. Unfortunately, fluorocarbon alphatic resin is more expensive, but you get what you pay for. And in this case it is peace of mind and easy maintenance.
If you're dealing with calcium based stones like limestone or marble, no matter what sealer you use, you cannot avoid the damage caused by acids. Anyone who tells you differently is wrong.
Is sealing granite easy?
Sealing granite countertops is as easy as spray on, let sit, and wipe off. There's no polishing, buffing, or strange applicators. It literally takes minutes. And if you're using a high quality alphatic resin granite sealer, you don't need to keep applying coats year after year.
As a fabricator and installer, we always degreased countertops and gave them their final cleaning with denatured alcohol. Denatured alcohol, it turns out, does wonders for cleaning granite and cutting through film buildup on your counters. The result is the original shiny surface.
When dealing with contractors of any kind, quality referrals are your best way to avoid the frustration and hassle. And it's why you should consider a referral source like Angie's List to help you find any kind of contractor, not just granite fabricators and installers.
Now, knowing that the resin is absorbed for the purpose of sealing the stones natural pores, it stands to reason that an impregnator cannot, and does not, offer any protection whatsoever to the surface of the stone - physical or chemical damage such as scratches or etching by acids.
We researched and tested several granite sealers before choosing MB-4. With more than 10 years of proven performance using MB-4, it's the only sealer we'll use.
Don't trust your granite investment to anything else.
Why should you seal granite? Granite is a natural product and inherently porous. It can stain.
Many granite companies use poor quality silicon or siloxane based sealers that require re-application every 6 months to a year. These sealers create misconceptions about sealing granite.
Professional grade MB-4 is a fluorocarbon alphatic resin sealer. Unlike silicon sealers, it will not evaporate or go through any type of natural deterioration. MB-4 sealer for granite prevents liquids from being absorbed by all natural stones - marble, granite, travertine, and limestone - and comes with a 10-year warranty.
Fluorocarbon alphatic resin is more expensive . . . but you get what you pay for. And in this case, it's peace of mind and easy maintenance. The 32 ounce bottle is a lot of sealer too.
Applied properly, this sealer will last 10 to 15 years and you don't need to reapply before then!
Full instructions and you're done in minutes! Here's how to seal granite countertops.