The Polished Perspective
Sealing 101 (aka Sealing for Dummies)
Tom McNall
Floor Restoration Contributor

I am always surprised at the number of times I see someone sealing stone the wrong way. Whether it is an installer, fabricator or janitor trying to break into the stone business.

For starters, I am talking about impregnating sealers here, not topical. What's the difference you may ask? Well for starters, a topical sealer is meant to be on "top" of the surface and an impregnating sealer is meant to be "in" the stone.

Now, that description can open a number of questions and theories from the neophyte to the veteran of the stone industry, and trying to dispel all of the rumors and doctrines in one article may prove challenging at best. So, I will focus today on the positive the right way to do it.

First things first Read Thy Label! I cannot tell you how many problems could be avoided with this one simple task. If a new (or old) employee asks me how to apply a product on (or in) stone, I will always tell him or her to read the label.

The new ones will push further, saying that it would be easier for me to just tell them, to which I reply, "So, you want me to read it to/for you? Because unless I am using that product every day, I would read the label myself, and if I am doing that, then why did I hire you?" That point usually gets them reading their first words since they wrote their resume.

Now, not all impregnating sealers were created equal, however, the basic gist of the top sealers that we use in our operation's instructions are as follows. Wet the surface with the product, allow to sit on surface for 5-10 minutes (I prefer the 10 over the 5 minutes), do not allow to dry, remove excess sealer and buff surface to remove residue.

Now, some instructions will suggest that you use their patented applicator or a roller of some sort. Here is the thing: The object is to make the stone wet with the sealer. If the stone will absorb the sealer and it is applied properly, the clear molecules in the sealer will crowd into the open space, much like college kids into a phone booth. When those molecules cure, there is no more room left in the stone for any staining agents to enter. It is a great plan.

However, if you pull a Mr. Miyagi and do the wax on, wax off approach, you are not allowing the sealer enough time to cl og the stone's pores. It needs the dwell time. Now, some stones will absorb the liquid quickly (about 10% of stones) and others will absorb little to none (the other 90%). In the 10% of stones that absorb a lot, you will need to do a second application.

Here is where most labels are wrong. They say you can apply another application after an hour. In reality though, it takes a lot longer for the clogging agents to cure properly up to 24 hours. No one wants to print that on their label, though, because then Mr. and Ms. Consumer would want to use a different product that allows them to seal quicker.

Another faux pas of sealing is the applicator. Again, the object is to wet the stone for 10 minutes. But when you understand the principles at work, you will understand why certain applicators will not accomplish the job that you want it to. A good impregnating sealer is basically two items. The clogging agents (they will cure clear) and the carrying agent.

The carrying agents job is to keep the clogging particles in a liquid state and, therefore, allowing them to penetrate (impregnate) the stone. Once exposed to the air, the carrying agent is meant to evaporate and, thereby, leave the cloggers to do their job. This is why a good impregnating sealer will not alter the appearance of the stone after curing. Simple right? Not always.

If you are applying an impregnating sealer with an absorbent product (like a towel, sponge, etc.), you are soaking up all of the "clogging material" into your applicator and just wetting the surface with the carrying agent which will evaporate quicker. One caveat, though, is that if your applicator is saturated, then the good stuff cannot help but overflow onto the stone. However, I rarely witness anyone applying with a saturated rag.

In our operation, if the area is small enough (countertop, stairs), we apply the sealer with a rubber glove (or nitrile, acrylic and such). On larger areas like floors, we spread the product around with a barn broom (never actually used in a barn, though). This way, all of the impregnating goodness is left on the stone, allowing 100% of what the stone will allow into it, into it. None soaking into the glove or broom.

Now, how do you remove the excess sealer and buff off the residue? Well, my friends, that is another adventure best explored next time.

Until then, keep your stick on the ice.

Tom McNall is founder and owner of Great Northern Stone, an Ontario-based stone cleaning and restoration company servicing Ontario and Chicago, IL. Tom also offers corporate and private consultations as well as speaking at conventions. He can be reached at .

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