All stone is porous, some more than others. For most stone—especially very porous stones like hone-finished limestone or certain granites—the application of a quality impregnating sealer is highly recommended.
The application of an impregnating sealer to highly-polished marble and travertine, or polished high-density granites, may not be necessary—but when in doubt, consider this: it doesn’t hurt to have it sealed. If it turns out that sealing the stone does, in fact, prevent some staining, you’ve saved yourself the cost of a stain removal service.
For some stones that are more porous than others, one application of impregnator/sealer may not be enough. But how will you know?
On granites that need sealing, at least two applications are recommended. Very porous granites, sandstone, quartzite, etc., may require three or more applications. When sealer can no longer be absorbed by the stone, the stone is adequately sealed.
There is no absolute rule of thumb when it comes to the durability of any sealer. Generally speaking, most quality impregnating sealers interior will last 2-5 years or more. Environment plays a big role. Stones exposed to intense heat or direct sunlight will probably need to be re-sealed more often.
To find out if your stone is perfectly sealed, pour some water on it and wait for approximately half an hour, then wipe it dry. If the surface of the stone did not darken, it means that the stone is still perfectly sealed. Be sure to test various areas, especially those areas that get more use and abuse.
Contrary to what your perception may be when you hear the word sealer, most sealers for stone are below-surface products and will not alter in any way, shape or form the
original finish produced by the factory. They will not offer protection to the surface of the stone, either. They will only go inside the stone by being absorbed by it (assuming that the stone is porous enough to allow this to happen) and will clog its pores, thus reducing its natural absorbency rate. This will help prevent possible accidental spills of staining agents from being absorbed by the stone. On the other hand, granite is more porous than marble and may stain if not protected with a good-quality, impregnator-type stone sealer. Stay away from topical sealer, waxes, and coatings. Some “granites” are so porous that no sealer will do a satisfactory job sealing them 100% for an extended amount of time.
Sealers for stones, which are below-surface, penetrating-type sealers—better referred to as impregnators—are designed to do one thing and one thing only: clog the pores of the stone to inhibit staining agents from being absorbed by it. In some instances, “weird” problems that may appear to be etching on “granite” counter tops turn out to be created by sealer residue that has left a haze on the stone or reacted with substances that had spilled on it. In these cases, once the sealer is professionally removed, everything is fine.
Note: Sometimes, marks of corrosion (etch marks) that an acidic substance leaves behind may look like water stains or rings, but they are neither stains, nor were they generated by water. The deriving (surface) damage has no relation whatsoever with the porosity of the stone (which determines its absorbency), but is exclusively related to its chemical makeup. Special topical treatments are becoming available for acid-sensitive stones that are designed to offer some protection from acids, while still allowing the stone to breathe. Ask us for more information on this.
While impregnating sealers will not alter the appearance of your stone, a color-enhancing (impregnating) sealer will protect the stone while bringing out its color, giving it a wet (i.e. darker, not glossy) look. It will at the same time provide good protection from water- based staining. Color enhancing sealers are typically used on tumbled marble, low-honed limestone and travertine, honed (black) granite, etc.
Cementitious grout is porous and will absorb liquids, which can potentially stain and result in the growth of bacteria. Sealing your grout provides a protective barrier that not only preserves it from stains, it makes routine cleaning and maintenance easier.
Grout can be sealed with a clear sealer or it can be color sealed. Color sealing has the added advantage that it allows you to completely change the color of your grout, whether it is just for a new look or to cover up stained and discolored grout.
Is sealing a job for the homeowner, or should you hire a qualified professional to do it for you? Consider the following pros and cons.
You save on labor costs by doing it yourself. However, consider the magnitude of the job and how comfortable you are with a DIY project. Are you prepared to get on your hands and knees to seal a floor? Are you willing to apply multiple applications if needed?
Has the floor or surface been thoroughly and completely cleaned? If not, you take the chance of sealing in dirt and debris. Also, keep in mind that sealer not completely removed from the surface of stone may cause problems, including a haze on the stone that may develop as the sealer dries completely. Once it is dried on the surface, sealer can be very difficult to remove.
Different sealers perform differently in different environments and on different stones. Hiring a pro to do the job may end up saving you in the end. A pro will know which is the best sealer for the job and will use equipment and techniques that allow them to get the job done efficiently.
Thanks for looking at our guide, if you have any questions feel free to contact us.
Assuming that your kitchen counter top is made either out of true granite, green marble or soapstone, or a hone-finished stone (if you have polished marble or polished travertine, then there’s not much that can be done to maintain their highly glossy finish, other than
. . . well, never using your counter top), there is one thing you must remember:
This firm rule applies to all stone surfaces—counter tops, floors, walls, etc.—using a “glass cleaner” or “water with a little dish soap” are common but erroneous recommendations that you may hear. Glass cleaners may turn out to be too harsh to both the stone and the sealer (if one has been applied). Water and dish soap can leave an unsanitary and unsightly film that will build up and become problematic to remove. (Wash your hands with dish soap and then rinse them under running water; observe how long and how much water it will take to rinse properly. To get the same rinsing result—which is the only one acceptable—for your counter tops, you would have to rinse them with a garden hose!)
Generic household cleaners off the shelves of the supermarket are out, and specialty cleaners specifically formulated to deal with the delicate chemistry of stone are, very definitely, in order.
DO'S
Treat your counter tops to a conditioning stone polish occasionally. It can do a terrific job at brightening up your polished stone surface. Be sure that the ingredients are classified as “food-grade.” As with all the products, be sure to follow the label instructions.
DONT'S
Use any green or brown scouring pads for dried-on spills. The presence of silicon carbide grits in them will scratch even the toughest granite. You can safely use the sponges lined with a silvery net, or other plastic scouring pads. REMEMBER: it’s very important to spray the cleaner and let it sit for a while to moisten and soften the soil, before scrubbing. LET THE CLEANING AGENT DO THE WORK! It will make your job much easier and will be more effective.
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Natural stones—especially calcite-based stones such as marble, travertine, limestone and many slates—may have a delicate chemical composition that could potentially interact in “strange” (damaging) ways with cleaning solutions that were not specifically formulated for the task. In fact, one of the most common reasons stone restoration services are required for both residential and commercial applications is that the wrong cleaning products were used. We frequently get calls from frantic customers telling us they followed the advice of someone who is not a professional and used vinegar and water to clean their marble, and now they have rough white spots where they cleaned. Or, they used some bathroom cleaner that etched their stone.
Once you know WHAT to use, all you have to do is follow some basic guidelines and your natural stone installation will give you years and years of beautiful service. Find our handy guide below for the do's and don'ts of routine cleaning and cleaning up spills.
DO'S
Avoid cleaning products unless the label specifies it is safe for natural stone. This includes glass cleaners to clean mirrors over a marble vanity top, or a liquid toilet bowl cleaner when the toilet is on a marble floor.
DONT'S
Place hot items directly on the stone surface. Use trivets or mats under hot dishes.
Some spills will turn out to be detrimental to stone if unattended. Orange juice, lemonade, wine, vinegar, liquors, tomato sauce, yogurt, salad dressing, perfume, after shave, the wrong cleaning products and so on—through a long list—most likely won’t damage “granite” and “green marble” surfaces (at least in the short run), but will ETCH marble, travertine, limestone, onyx, alabaster and many slates. Therefore:
DO'S
Pick up any spills as quickly as possible.
DONT'S
Use cleaning products on or near your natural stone unless the label specifies that it is safe on natural marble. (Cultured marble is man-made and is basically a plastic material.) This includes glass cleaner to clean the mirror over a marble vanity top, or a liquid toilet bowl cleaner when the toilet is on a marble floor.
Thanks for looking at our guide, if you have any questions feel free to contact us.