natural stone wall

Should natural stone be sealed?

As one of the oldest construction materials still in use today, natural stone can be found in many outdoor structures. The Seven Wonders of the Ancient World all featured natural stone, and this inspired Roman and later Italian architects to continue using limestone, travertine, marble, granite, and other metamorphic rocks to build ancient and magnificent structures such as the Colosseum. Suppose you travel to Rome and visit the Colosseum these days. In that case, you will notice very few of the exterior travertine blocks, which were extracted from the quarries at Tivoli, have retained their original golden hue, and this is because sealant for natural stone would not be formulated until many centuries later. Had ancient masonry and stonework experts been able to apply sealant, the magnificent structures they built would be in much better shape today. If you have a stone in the outdoor areas of your home, it’s best to keep it sealed.

Natural stone is porous, which means it has interconnected capillaries through which liquids and gases can move. Porous materials act as a hard sponge and suck in liquids over time, along with any dissolved salts and other minerals or contaminants (stains). More porous stone, such as sandstone will absorb liquids relatively quickly. In contrast, denser volcanic stones such as basalt are significantly less porous and may take longer to absorb oils and water-based liquids. Natural stone should be protected against sub-surface staining, everyday dirt and spills; this can be done by sealing the stone in 1 of 2 ways, a penetrating or topical sealer.

Topical sealers can alter the surface texture and finish, as well as build up on the surface, creating a layer that is less durable than the stone. Penetrating (impregnating) sealers are carried into the stone by either solvent or water. The carrier then dissipates bonding the sealer resins with the stone. This process doesn’t alter the slip resistance or natural look of the stone. The deposited resins then create an oleophobic (oil-repelling) and hydrophobic (water-repelling) barrier which prevents subsurface staining. These products are considered “breathable,” meaning they allow for vapour transmission. Spirit Water-Based Premium Seal is on the cutting edge of this type of technology and is the perfect product for both DIY applications & commercial.

Natural stone has become a sought-after choice for fireplaces, countertops, flooring and more because of its natural beauty and durability. There are many different types of natural stone available, each with their attributes. Among the most popular options are marble, limestone, travertine, slate tile, and granite. Because it is porous, sealing natural stone on occasion will help to prevent stains and the growth of bacteria.

Fortunately, sealing natural stone flooring or countertops is a relatively inexpensive task that only has to be done once a year (at most). Some products work for multiple years, making it a simple maintenance chore that will drastically extend the life of your natural stone.

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Determining How Porous Stone Is

The type of stone you have plays a major role in how frequently sealing the stone is required. A simple water test will determine how porous your stone is. Place droplets of water directly on the stone and see how long it takes for the water to absorb into the stone. If the water penetrates the stone quickly, it is very porous. If the water sits on top for longer, the stone is less porous.

Among the most porous varieties of natural stone are marble, onyx, and limestone. Without a sealant, these stones stain very easily. Sealing these stones every six months will help them continue to look like new. If you are looking for something more durable from the start, granite and quartz make great choices. These stones are easy to clean with soap and water and only require a sealant once a year.

natural stone wall

Three Types of Sealants for Stone

Most new countertops and backsplashes arrive already sealed, eliminating the need for an initial coating. Down the line, sealing the stone again will help to preserve the look of the natural stone and prevent stains. Today, some stones feature resins that act as a built-in sealant, eliminating the need for an additional coating. If you have determined that your natural stone does require a coating, there are three main types of products to consider:

Surface Sealant

A surface sealant is also referred to as a strippable coating because it is applied to the surface only and is easy to remove if necessary. It is typically a water-based sealant containing polymers, such as acrylic. Because surface sealants are also available for tile floors, it is important to ensure that the product you select is intended for use on natural stone. Surface sealants are less of a commitment, but they also need to be reapplied regularly.

Penetrating Sealant

Penetrating sealants are commonly referred to as permanent coatings and are much more difficult to remove than a surface sealant because they are crafted of solvent-based polymers.

Impregnating Sealant

An impregnating sealant is a solvent-based formula that requires a professional application. They have become a popular choice for sealing outdoor stone because they are not affected by UV light and don’t alter the appearance of the stone. Although the professional application is required, this sealant typically lasts for several years before another application is needed.

When Should You Seal Natural Stone?

To make things as easy as possible, we’ve put together this helpful schedule to help you keep tabs on that lingering question – how often should I seal my natural stone?

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Sealing Your Concrete Driveway

Concrete driveways are often forgotten when it comes to sealing. It’s easy to tell when an asphalt driveway needs sealing because you can see the colour lighten over time. Concrete can be more difficult to tell when it needs sealing.

Concrete is extremely durable, so it doesn’t require frequent sealing. Most experts recommend resealing your concrete driveway once every five years or so. Depending on your climate, you may be able to wait a little longer than five years. If you start to notice cracks developing, call a professional to assess whether or not it’s time to reseal.

Sealing Your Granite Countertop

There’s an easy test that will tell you if your granite countertop needs a new coat of sealant. You can test the absorption rate of your granite to determine how much and how often you should seal.

Pour a ¼ cup of water onto your granite countertop and note how long it takes to absorb.

If the water absorbs immediately, you should apply a few coats of sealant each year and be quick to wipe up spills to avoid staining.

If it takes 5 – 10 minutes for the water to absorb, you should still apply several coats of sealant, but you can reapply every 3 – 5 years.

If it takes 30 minutes or more, your countertops are well-sealed, and you don’t need to do anything!

Sealing Your Natural Stone Outdoors

Many people wonder how often I should seal my natural stone outside. Natural stones, such as flagstone, limestone, or slate, are used for all manner of indoor and outdoor construction. Usually, these stones are incredibly durable, but it’s important to seal them every few years to ensure that they stay looking their best.

When sealing the outdoor stone, it is important to apply a water repellent to the grout between the stone as well. Grout and mortar are often more susceptible to water and ice damage than the stone itself. If the grout is left unsealed, it can crack, crumble, and in serious cases, expand and push the stone apart.

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Sealing Your Shower Grout

Sealing the grout between your shower tiles is incredibly important. Unsealed grout can crumble away and lead to disgusting mould in your shower. Most experts recommend that old tile work is cleaned and resealed each year, and new tile work should be resealed every six months to a year.


Pre-sealing is a term used to describe sealing the tile or stone prior to laying. The benefit of this is that it reduces the porosity of the tile/stone and works like a grout release. However, the main reason is to prevent the possibility of watermarking. Watermarking is reverse staining that occurs when a piece of stone is exposed to water and chemicals generally associated with high alkaline types of cement or other fixing materials. This moisture is absorbed into the dry stone which can add minerals and dissolves existing minerals in the stone. As this moisture dissolves and migrates through the stone then works its way to the surface to dry, the minerals are unevenly left behind and almost always alters the colour of the stone. The problem with that is that the contaminates show a much darker colour than the balance of the stone and a resulting stain remains and can be impossible to remove through cleaning efforts. This stain is often on the edge of the stone where the grouting occurs, and the mark can surround the tile and look like picture framing. Another form of this type of staining is where areas of the stone will have a blotchy effect at any location on the tile. The same effect but random throughout the tile. The pictures below show a few examples of watermarking. The first picture has staining from moisture from the glue, and this could’ve been prevented by pre-sealing the back of the tiles. It would be fair to note that up to the present, there is no known method for removing this marking. It is also fair to note that the use of Spirit Pre-Seal will prevent this from occurring.

Maintenance is the key

Once a natural stone has been sealed, maintaining the finish is very important, regular cleaning will allow you to keep the floor looking new. Sweeping and vacuuming the floor should be done as often as possible; this will help remove loose debris and reduce the amount of soil settling in the grout joints. A wet mop should be used afterwards to remove the rest of the soil, and a ph neutral detergent such as Spirit Neutral Cleaner must be added to the mopping liquid. Acidic and strong alkaline cleaners should not be used on a regular basis as these types of cleaners can damage the sealer and the natural stone. Heavy traffic areas will need a scrub on a more regular basis with either a nylon scouring pad or a bristled brush depending on the finish of the surface.

Newly Installed Tiles

Properly removing excess grout smear left from the tiling is one of the most important things to do, if not removed completely it can make maintaining your tiles a nearly impossible task. Acid cleaners are designed to remove stubborn grout residues, and however, when used incorrectly, they can damage the tile surface. Spirit Marble & Tile Care are experts in stone & tile, and they can assist you on which cleaners are appropriate for your particular situation. Some natural stones are acid sensitive, ie. Marble, Limestone, Travertine and other calcium-based stones. If an acidic cleaner cannot be used, a good quality detergent such as Spirit Neutral Cleaner will do the job. When cleaning acid-sensitive stones it is important that you remove all the grout smear between 3-5 days from grouting, this allows enough time for the grout to cure in the joints but still be easily removed from the tiled surface. If the grout smear is left on for too long, it can bond to the stone and may need to be removed by regrinding the surface. When using acid cleaners, it is always a good idea to rinse thoroughly and neutralize the tiles so that all the acid residues are removed.

Clean between the lines

Grout joints can be a major problem as they are recessed, porous and textured. When you’re mopping, the combination of friction from the mop and the wetting agents from the detergent loosen the soil from the tiles and send them into the grout joints which absorb the dirty water, and this will build up and become unsightly. To help with this problem, Spirit makes it easy to use sealers to reduce the absorption and assist with this problem, and this is also very important in wet areas where mould and mildew occurs. Using bleach type products regularly is not ideal, although effective, these products are bad for your health, grout and the environment. By sealing and maintaining the joints, you will reduce the use of harsh, expensive cleaning products and allow your grout always to look clean and uniform.

Spirit Marble & Tile Care

Our goal is to provide as many home users and professionals high-quality products that assist them in protecting their valuable tile and stone assets, reduce cleaning time and reduce the need for harsh cleaning chemicals being used and entering our environment. At the same time educating the industry to prevent tiles and stone from being damaged through incorrect laying procedures and incorrect cleaning products being used. Our website provides valuable information to the public regarding care & maintenance and correct cleaning methods. The website also provides key product information to ensure the optimal application and performance of all Spirit’s products.

Pros of Sealing Natural Stone

Taking the time to add a coat of sealant to your natural stone can provide many benefits. Not only does it protect against stains, but it also helps to prevent acid erosion and bacteria growth. This step also helps to keep any outdoor stone from being susceptible to frost weathering and salt damage. On the floor, some coatings even add a layer of slip resistance, ensuring sure footing. Check out our article on the pros and cons of sealing your pavers for more specific information about outdoor patio flooring.

Cons of Sealing Natural Stone

As with anything, sealing floors has drawbacks as well as benefits. Unfortunately, sealing natural stone is a relatively frequent chore. Depending on the type of stone, it could be required as often as every six months. If an impregnating sealant is used, it may only be required only every one to three years. Even with proper application, there is always a chance that the sealant will not fully protect against stains. It is still good practice to wipe up any spills or standing liquids promptly and not allow them to sit for long, especially on countertops. Some sealants can tend to show wear patterns on the floor by becoming dull in areas that receive the most foot traffic.

Its natural beauty and durable design make natural stone a popular choice for floors, countertops, bathrooms, and outdoor living areas. Keep it looking as spectacular as the day it was installed by properly sealing the stone when needed. Sealants help prevent this naturally porous material from stains, erosion, and wear while highlighting the beauty of the material. Weighing the pros and cons of the process and understanding the differences in the products will help you choose a sealant designed to prolong the life of your stone.

How often do you need to reseal your natural stone?

First, consult the brand of sealer that your fabricator initially used, as some sealers have warranties. All stones have different porosities, and different finishes can lend to higher stain resistance as well. Learn more about the porosity of your stone and use your best judgment. If you see water spots or anything out of the ordinary, then call your fabricator to refinish. The maintenance could be every year or every five years, and it depends on the stone and the type of finish.

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