How to Seal Marble

  • June 13, 2020
  • / By Dale Keese
Cat on Marble Steps

Interiors have always been grander with marble. The stone has become a popular material for houses and commercial establishments. This soft, calcium-based stone is usually cut into tiles or slabs. These are then used to build flooring, countertops, and other structures around a house. It is a strong and durable material which is why builders use it so frequently.

Cat on Marble Steps

However, with all its advantages and aesthetic appeal, marble is a porous material. This means that it can absorb moisture and other types of elements from liquids. When marble is used to build a countertop, water contact is high. To prevent stains, sealing marble is very important

Sealing is not only required to protect marble from becoming stained but also for maintenance. Marble is easily damaged and also prone to etches, which means that it needs to be regularly maintained. Sealing can prevent marble from deteriorating. If the right marble sealer is used, the marble can be effectively protected.

A sealer essentially acts as a defense against damage to the marble. Therefore, applying a sealer specially made for marble is a critical finishing step. Using the wrong sealers can have the opposite effect and harm the quality of the marble.

In simple terms, a marble sealer is an element that works as a protection for marble. It is applied on the surface to solidify the pores of the marble, which prevents any foreign elements from entering the pores and causing damage to the quality and life of the marble. Clogging the pores through a marble sealer ensures that there will be no stains on the marble due to impurities absorbed from water.

Natural Stone Patterns

The solvent in marble sealers penetrates the pores of the marble and contains a solid resin that ultimately gets left behind to plug in the holes. Essentially, marble sealing is a binding process where a sealing solvent is applied on the surface of the stone.

Liquids and some gases can permeate marble through its pores. When a sealer solvent is applied to its surface, it blocks the pores and prevents the environmental impurities from trickling down and clogging these pores. This prevents the marble from losing its natural color.

A common myth is that a sealer does damage to the original polish and color of the marble. A sealer in no way damages the surface appearance of the marble. In fact, there are impregnating sealers that are applied below the surface and are absorbed by the stone. They do a great job of preventing marble from forming stains. 

A marble sealer cannot be used as a polisher or a shiner since it has no extra shine to lend to the surface nor does it protect the original shine of the marble. Polishing does not prevent the stone from its normal wear and tear.

Why is Sealing Necessary?

Understanding the need for a sealer is extremely important when applying it on the surface of your home or office.

Marble is used in floors, kitchen countertops, as well as bathroom tiles.With such widespread use of marble, it is necessary to know all the possible ways it can get damaged. Here are a few threats to marble that make sealing necessary.

Home Decor
  • Staining is the most prominent threat to the original quality of the marble. Staining can happen not only in the kitchen but also in the flooring of all rooms. Staining is caused by permeation of any liquids or oils in the pores of the marble that can result in damages to the surface.
  • If you have used marble in any outdoor structures like columns and walls, there are high chances that it can get damaged due to acid rain. Acid rain results in erosion of the stone and leaves stains on the surface of the marble. The acid, when it seeps into the pores, can damage the entire structure from the inside. Other household goods containing acid include cleaning solvents, milk, lemon juice, and wine. If the liquid contains strong acids, it does not take more than a few seconds to cause permanent damage to the stone while it might be a slower process with weaker acids.
  • Water is another major threat to marble. If water enters the surface of the marble and freezes, it expands below the surface, causing the marble to weather down and develop cracks.
  • When water evaporates from the surface, it leaves minerals behind and causes efflorescence, which is the formation of a white sandy deposit on the surface of the marble floor. It causes the marble to lose its shine and polish.

Types of Marble Sealer

There are different types of marble sealers on the market that can be used depending on the kind of application needed.

Geometric Floor Tiles

Topical Sealers

Topical sealers are the most basic type of sealers. Made from natural wax or acrylics, these are surface sealers and can be used to prevent stains from developing on the stone but are quick to wear out. They do not provide protection against efflorescence and alter the characteristics of the surface of the marble causing the vapors to stay inside.

Penetrating Sealers

Penetrating sealers are good at preventing liquids from causing damage to the marble. Containing siliconates and fluoro-polymers and similar substances, these sealers permeate through the surface of the stone and last much longer than topical sealers. They also do nothing to the original appearance of the stone and only change the characteristics of the surface to prevent it from damaging.

However, like topical sealers, penetrating sealers are not strong enough to protect the stone against damage caused by efflorescence.

Impregnating Sealers

Impregnating sealers are the most advanced marble sealers that contain modified silanes. They have the strength to percolate deep inside the surface of the marble and bind the pores with its molecules which ultimately prevents liquids like water and oils from seeping into the surface.

Impregnating sealers are also effective against frost weathering and efflorescence since they are able to penetrate deep into the canals and fill the holes quite well. They do a better job of preventing damage to the marble from the external environment. The extreme penetration is effective in preventing damage against erosion and UV light as well.

Marble sealers are used after the application of a special type of cleaner that clears the surface of all residual harmful elements that have collected on the stone. Once it is cleaned, then the sealers are used for maximum effect.

How Do Marble Sealers Work?

A marble sealer is designed to prevent liquids from penetrating the pores of a marble top or flooring so that there will be no stains or damage.

Vintage Bathroom Sink

A sealer contains a solvent carrier that is designed to penetrate into the pores and settle down the solid resins. The resins, in turn, clog the open pores and prevent the foreign impurities from percolating into the surface and forming stains. There are impregnating sealers that work from below the surface once the marble surface has been cleaned using special cleaners.

An important point to remember here is that even though marble sealers are considered to be the best way to prevent marble from getting damaged, they are ultimately an external solvent. The marble still needs to be looked after regularly to maintain its polish and shine. Even though you already applied a marble sealer, it is always a good idea to use a cleaner immediately whenever there is a spill. 

The sealer must be physically absorbed by the stone to do its job. However, there are stones that do not absorb the sealer and let the liquids seep into the surface. The absorption rate of some marble stones is less than 0.2% which means that it also cannot absorb liquids. In such cases, there is no use applying a sealer on the surface. It might end up harming the marble more than it might benefit it.

A sealer that is not absorbed ultimately reacts like any other liquid and leaves behind stains once it has evaporated, unless it is absolutely wiped from the surface. Moreover, since the sealer contains solid resins, they also get left behind creating a gritty surface and spoiling the original shine of the marble.

How to Seal Marble

A marble sealer, if not used properly, can do more harm than good to the surface of the marble. There are specific steps one needs to follow to effectively seal marble. Let us take a look at the steps on how to seal marble.

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Clean the Surface

Before applying a marble sealer, the first step is to clean the surface of the marble with a soap and water solution. While any normal soap used to wash utensils might work fine, it is always better to use solvents that are designed specifically for stone surfaces for more effective results. This is especially if the surface is a kitchen countertop that has been weathered by exposure to cooking oils and other kinds of liquids that accumulate grease.

A marble cleaner removes grease and cleans the surface thoroughly. Once the surface has been washed, it needs to be rinsed again with clean water and then left to dry completely. This will ensure that all impurities that might interfere with the properties of the sealer are completely removed from the surface.

If you are sealing a specific area of the marble only, ensure that all other areas are properly taped off. Chrome and steel surfaces around the marble surface need to be covered before applying the cleaner and the sealer to avoid causing any damage to them. For this purpose, a high-quality taping paint can be used.

Apply the Sealer

For convenience, pour the sealer solvent into a container with a large mouth so that you can easily dip the paintbrush into it for application. To make sure that the smell of the sealer does not cause any harm to the user, keep the area well-ventilated to allow the VOCs in the sealer to escape the room. 

Once this is done, dip the paintbrush in the container and apply the sealer on the counter or any other marble surface with two to three repeated strokes that overlap each other. Ensure that all areas under the marble surface are covered by the sealer, including the edges and areas around the sink if it is a countertop.

Do not disturb the coat once applied and let it dry for at least 15 minutes up to half an hour. Leaving the sealer on the surface this long allows the liquid to seep into the surface of the stone and effectively spread into the pores to plug them against any harmful liquids. 

Before sealing the entire surface, it is a good practice to apply the sealer on a smaller area first. It is best to test whether the sealer is compatible with the stone and does not harm the surface by discoloring it. 

Once the sealer dries in the test area, compare the color to the larger area, check the difference. If the color difference is too obvious, then the sealer is not compatible with the stone. The only difference should be in terms of glossiness of the surfaces.

Add Another Coat

If you are looking for extra durability, you can add another coat of sealer on the surface once the original strokes have dried. This is especially important if it is an overused marble surface like a kitchen countertop. 

Some sealers come with instructions and suggest the use of a foam brush for application. Therefore, ensure that you read the instructions carefully before sealing.

Wipe the Surface

Once both coats have dried, wipe the surface with a clean and dry soft towel or cleaning cloth. Keep cleaning the excess sealer with the clean cloth in a circular motion until the surface is absolutely dry and does not feel sticky. Excess sealer, if left behind, spoils the finishing of the surface. It is important to clean the excess off. 

The marble surface can be used about eight hours after applying the sealer. How long before you can use the surface again depends on the environmental conditions like humidity and temperature. Generally, it might take a day for the surface to become completely usable again. While it is fine to use for light purposes, full and heavy use of the surface should only be done after a day.

Swimming Pool

Factors Influencing Absorption of Sealer

Not all stones are the same. Each marble stone can be different in terms of color, porosity, and hardness. While some stones instantly absorb liquids, others take a long time for liquids to seep into them. It is safe to assume that all stones will react differently to different types of marble sealers. 

Another factor that influences the absorption of the sealer in the stone is the surface finish of the marble. A polished marble finish tends to have a lesser absorption capacity than the surfaces that are naturally left unfinished. This is because when the marble surface is polished, a lot of pores are filled and hence, the porosity of the stone is significantly reduced. This means that polished marble stones also absorb other liquids lesser. 

Similarly, honed marble surfaces also absorb lesser than the naturally unfinished marble. Honing the marble surface reduces the pores and thus reduces the absorption capacity of the marble. Like polished marble, honed marble also absorbs lesser liquids and is less prone to damage. 

These differences in the basic characteristics of the marble surfaces decide whether the marble sealer will work on the stone or not. To determine whether it will absorb the sealer, there are ways to test the properties of the marble. 

You can run the water test on the surface and decipher if the stone will benefit from the sealer or not. This is also useful in cases where you are not sure how much time has passed since the surface was sealed.

To conduct the water test, you need to pour water on different areas of the surface. The area covered by water in different spots can be about three inches in diameter. Leave the water on the spots for about half an hour.

If the spots start to get dark and stain, it is time to seal the surface again. On the other hand, if the water does not penetrate and begins to pool on the spots, sealing is not needed.

The Probability of Staining

When it comes to sealing, what matters is how fast the marble surface absorbs liquids and whether the liquids will leave a stain behind and damage the marble surface. This is more important probably for surfaces that are frequently in contact with damaging liquids like cooking oils and dishwashing liquids as they contain acids and other elements that can cause severe harm to the surface of the stone.

Something as overused as a kitchen countertop will definitely require sealing. since itMarble countertops regularly faces the damage caused by liquids that can cause stubborn stains used in the kitchen that holds immense power to stain it. If it is absorbing these liquids, using a marble sealer will prove to be a lifesaver with respect to its durability and overall strength. 

When we talk about shower marble, it barely comes in contact with such liquids that might cause stains.The closest threat would be the formation of mold, mildew, and grout stains. It is best to get a sealer that specifically deals with these issues for bathroom marble.

Modern Minimalist Kitchen

Maintaining a Marble Surface

Maintaining a marble surface is imperative if you want it to last. This means that reapplying the marble sealer is necessary as the years go by.

Not maintaining the marble stone results in severe consequences. With the slightest neglect, irreversible damage can be caused to the stone in the form of stains over time. These stains, if not taken care of immediately, etch hard into the surface and become impossible to remove. You will need the services of a professional to refinish the marble surface all over again, which is expensive. 

All of this can be prevented by following a simple maintenance routine.

Regular Cleaning of Counters

The counters and other marble surfaces should be cleaned regularly with a dry, clean cloth to wipe off any impurities resting on the surface. While it is alright to use normal dishwashing liquids, it is more beneficial to use specially designed marble cleaners that contain solvents to remove hard stains from the surface.

Regular household cleaners can cause more damage over time and cause the surface to lose its luster. Oil stains on a countertop can be removed by applying a paste made out of a mixture of baking soda and acetone. Similarly, hard coffee stains can be cleaned by using bleach and water and dried with a soft towel.

Regular Use of Sealer

Using a marble sealer after cleaning the surface is important the first time the surface is installed. However, it is also important to keep resealing the marble surface every couple of years or as needed. The stone loses its sealing properties over time due to common wear and tear and overuse. There are ways to test whether the surface needs to be sealed again.

If you do not want your marble surface to deteriorate, keep checking regularly whether the surface is in need of reapplication. You can run the water test frequently. Keep in mind that you can not overseal a marble stone; therefore, even if you seal it frequently, it will cause no harm to the surface.

Running in the Hallway

Final Thoughts

Sealing marble is important if you want to maintain its color, porosity, strength, and durability. Sealing is also a vital way to increase the lifespan of the stone. Failure to maintain it properly only proves to be more expensive since any damage will have to be fixed by a professional who will most likely refinish the stone.

It is equally important to know whether the marble stone you have installed needs sealing or not. Some stones, mainly the ones with natural finishing, do not need sealing since they do not absorb liquids.

Either way, you can make the beautiful marble interiors of your house last longer with regular maintenance and sealing. This will allow you to enjoy the glamour and aesthetic appeal of marble for many more years to come.

About the Author

Hey guys, thanks for reading.. hopefully this article can save you some time and trouble with your sealing job. I'm also in the process of making some video walk-throughs for youtube so check back soon! thanks

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