How To Seal Granite

How To Seal Granite The RIGHT Way!

Here's how to seal granite. But why should you seal granite tops in the first place? Sealing granite is such a misunderstood practice and worse, a misused marketing weapon.

It's the result of ignorance in the stone industry and maybe even malicious intent by sales and marketing people representing competing countertop materials.

Often, it's believed that when a material is delicate and hard to maintain, it should be sealed. The stone industry set out to solve the concerns of granite countertop staining by soliciting chemists to develop a sealer for stone.

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"Seal Granite ONLY If It Needs It Or Risk Altering The Performance And Appearance Of Your Stone!"

Unfortunately, the chemists didn't understand petrography.

Granite sealer, the miracle in a bottle, became what I consider one of the most over-promoted, over-rated, and over-applied products you'll find.

See GraniteCarePro for professional sealing and cleaning products for your countertops and kitchen.

What Is Granite Sealer?

Stone sealers or impregnators are below-surface penetrating sealers, not topical hard shell sealers such as those used on wood floors or furniture. The sealing substance is delivered inside the stone by natural absorption.

Some stones are less dense and more absorbent than others. Granite sealer consists of a solid part, or resin, and a solvent or water carrier.

The solid is the part that seals the pores of the stone. The carrier is what brings the solid into the stone.

The most important part of stone sealing is to thoroughly clean the surface prior to sealer application. This prevents changes to the color or the finish of your stone surfaces.

See Granite Sealers for suppliers of high quality sealer.

Several commercial granites won't absorb anything because they're so dense. Therefore impregnator will never be absorbed.

If you apply it anyway, some will remain on the surface of the stone and it will give the impression that the stone is damaged.

This damage will appear in the form of "ghost water stains" or "water rings" and confused for granite water stains. Some of the best stone surfaces can look "stained" after sealing them. When in fact, the sealer is what is stained.

Don't seal granite counter tops if they don't need it. See Granite Stain Removal for more info.

How do you know if sealing granite is necessary?

Take the Lemon Juice Test. Here's what I mean . . .

Different granites each have their own needs depending on how porous they are. Some granites never need sealer and should never be sealed (especially black stones). Others need several coats of sealer.

Granite is very different than marble or limestone, so make sure you are dealing with granite before anything.

Lemon Juice Test For Sealing Natural Stone Countertops

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 sealer.

If the lemon juice doesn't absorb at all, the stone does not need to be sealed. And contrary to what you may have heard, sealing granite isn't always a necessary part of granite care.

In fact, the performance of various granites can differ greatly. Some need sealer while others don't.

So how do you seal granite the right way?

First, understand that many granite installers use poor quality silicon or siloxane-based sealers that require re-application every 6 months or once a year. These sealers are unfortunately very common and many of the misconceptions about sealing granite come from their widespread use.

We recommend and use a fluorocarbon alphatic resin sealer. Unlike silicon sealers, these will not evaporate or go through any type of natural degradation. That's why the particular brand we use for all our sealing, MB Stone MB-4 impregnator, comes with a 10 year warranty.

Fluorocarbon alphatic resin is more expensive than lesser quality sealers, 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.

Sealing granite is actually easy

Sealing granite is as easy as spray on, let sit, and wipe off. It literally takes minutes. And if you're using a high quality alphatic resin granite sealer, you don't need to keep re-applying over the years.

As a fabricator and installer, we always degrease countertops and give 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.