Sealing Granite Countertops
Anyone who has asked the sealant question of more than one person in the stone business quickly realizes the answers can vary like the wind. Some answers are more windy than others. So we’ll try to keep this as straight forward as possible but it does require some explaining.
Why Granite is the way it is.
Granite is a natural product made up of interlocking crystals of feldspar, quarts and mica. Other materials that were absorbed by the magma as it cooled helped to create all the color variations and patterns you see in the world of granite. This is also the very reason why there are differences in density and porosity. There also may be natural micro fissures and pitting at crystal interfaces within the granite.
A word on Resin.
In the old days a lot of granite was discarded because of fissures and pitting. This was wasteful and caused granite to be extremely expensive. Then came resin technology which not only helped stabilize existing colors, it allowed some very striking colors to become available and affordable. These days most slabs are run through a vacuum chamber so the resin will flow freely into the voids like micro fissures and pits. Once the resin has hardened the slabs are then polished back down to the stone surface. So 99.9% of the surface you see and touch is the stone but any fissures or pits are filled with resin. This is why resined stone is stable but not considered completely sealed.
What’s a Sealant?
So here’s the scoop on sealants. There are many available on the market but the basic principle is the same. Sealants are design to penetrate pores and repel moisture. Some are water based while others use a petroleum or alcohol product to carry Silicon, Siloxane, Silane, or Acrylics deep into the pores. Water base sealants are generally the least expensive, mild from a chemical standpoint and can be applied by the “do it yourselfer”. Petroleum and Alcohol based sealants are typically applied by trained professionals and last longer. Some products are claiming up to 15 years.
How often should you seal?
That depends on what type of granite you selected, what type of sealant you’re using and what you choose to clean your granite with. Water based sealants can last between 1-2 years. Petroleum and Alcohol based sealants last between 5 and 15 years. All sealants will last longer if you wash your counters with mild soap and water. Bleach, Ammonia and other harsh cleaners will not hurt your granite, but will break down your sealant much more quickly. The best way to determine when you need to seal is to sprinkle water on your countertop. As long as water beads up you’re fine.
Despite what you may have heard, sealing granite yourself is EASY! If you can work a spray bottle, set a timer and wipe, you’re more than qualified. Make sure the countertops are clean and dry. Spray the sealant over the entire surface of the countertop. Let it sit for 30-40 minutes. Some areas may appear to be dry. These are areas that need sealant the most so spray the dry areas again. Allow the counters to set another 20 minutes and then wipe them clean. That’s it.
How much does it cost?
A quart bottle of water based sealant cost in the range of $40 – $60 and will be enough to seal most kitchens. Most fabricators will seal your countertops as part of your install so if they are new, you may be Ok for some time. Just do the water sprinkle test from time to time. Petroleum and Alcohol based sealants are usually professionally installed and can cost $200 – $500.
The Brass Tacks
Keep in mind that sealants are a fairly recent innovation to the stone industry. Granite rarely stains easily even without sealants. Sealants make staining even less likely. By chance if you do manage to stain your granite don’t panic. There are a number of granite poltice recipes that can extract some very tough stains from countertops. If you’re not comfortable doing the poltice yourself, there are granite and marble restoration services that can do it for you.
There is no other surface on the market that can give you the natural beauty and the solid durability of Granite. Engineered stone is in many ways a functional equal to granite. So if you want the color options of Formica, then engineered stone may be for you. As for the question of porosity and bacteria, both Granite and engineered stone are 1000 times cleaner than laminates. Most of us in America grew up with laminate countertops without issue so it’s safe to say the bacteria claim on Granite is a non-issue.
So that’s everything you should ever need to know about sealing Granite Countertops. If you ever have questions about the characteristics of a particular type of Granite please come and see us at EleMar. We’ll be happy to explain the details.