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How To Seal Marble Countertops Like A Pro

Shiny, smooth, and providing a visual appeal — a marble countertop is a pleasant addition to any kitchen. But your countertop needs regular maintenance to preserve its original condition.

Sealing is a common maintenance task that comes with owning a marble countertop. By using a marble countertop sealant, you protect the surface from staining and etching and save money on costly finishes.

In this guide, you'll learn all the basics of sealing marble countertops and other natural stone countertops. Find out how to seal your countertop, when to do it, and how to ensure a proper seal. 

Why Should You Seal Marble Countertops?

In its basic form, marble is a porous rock that readily absorbs liquids. With time, those liquids you spill while cooking will seep into the stone and leave noticeable stains. Of course, the discoloration happens gradually until you suddenly have an unsightly surface for a kitchen countertop.

sealing marble countertops

Stains are the least of your problems. By refusing to seal your marble kitchen top at least once a year, you leave it vulnerable to etching. 

Have you noticed small marks on marble surfaces that won't go away no matter the amount of scrubbing? That's what etching looks like. Etch marks rarely looks pretty on any kitchen countertop and takes only a professional do-over to fix.

Marble is a carbon-based rock, which means acids can eat into the surface easily. The chemicals eat deeper in the stone and discolor the area with each spill of lemon, vinegar, or any acidic substance.

Professional quotes for finishing marble countertops start at $200, and the costs can quickly add up if you have a sizable kitchen surface. In comparison, a bottle of sealant can cost you between $20-$50. That's why using a marble sealer is an important step to prevent stains and keep your natural stone countertops looking great. This is one of the many ways to increase the aesthetics in your kitchen.

How Often Should You Seal Marble Countertops?

Marble countertops need re-sealing at least 1-2 times per year. You may, however, need to apply sealant more frequently, depending on various factors.

If your kitchen top gets many spilled liquids, it'll need more sealant than average. Those liquids break down seals quickly and expose the top layer to stains and etching. Also, remember that the sealed coating will only thin out as you clean the marble surface regularly.

It’s essential to include sealing into your natural stone countertop maintenance checklist. Perform this quick water test at intervals to know if your kitchen top is due for another seal:

  1. Pour water on the marble and let it pool on the surface.
  2. Check for any signs of darkening — if the surface darkens within 30 minutes, you need to seal the surface.
  3. If the water beads on the surface, the sealant is still actively protecting the countertop.

You could also conduct the water test some weeks after sealing the marble countertop. That should help determine how often you may need to re-seal the surface to prevent discoloration.

How to Seal Marble Countertops: A Guide for Homeowners

Sealing your marble countertop can save you a few bucks on house maintenance costs and leave your kitchen looking great all year long. Here is a simple guide on how to seal your marble counters properly:

white marble sealer
  1. Prepare The Surface

If a water test shows you need to seal your countertop, the next step is to prepare the surface. Remove all objects from the location to avoid getting sealant on them. Next, clean the surface with a granite cleaning solution. Make sure to avoid using regular cleaning agents during the cleaning process if you want to preserve your marble.

You want to mask off the edges so that sealant doesn't drip and stain your kitchen's surfaces. It's possible to use masking tape to divide the countertop into sections — this helps you keep track when applying sealant.

  1. Apply Sealant

Your choices for sealants are between solvent-based sealants or water-based sealants. Both have their pros and cons, which you'd do well to consider before buying.

Solvent-based sealants can be applied directly to the stone — do that in sections, so you don't go over the same place twice. Allow the adhesive to sit for 10-15 minutes, and rub it in with a soft cloth. While you want the sealant to penetrate the stone, ensure that it doesn't coat the surface.

For water-based sealants, you follow a similar sealing process of working the sealant into the surface. A takeout container, foam paintbrush, and applicator pad are necessary for this task.

Start applying the sealant with a foam paintbrush, especially for the corners. An applicator pad can help you cover the wide expanse of a countertop in broad strokes.

As with spray sealants, you need to wipe off the excess liquid sealant and prevent it from creating a film on the surface. However, that should come after the sealant has seeped into the countertop. Buff the surface with a dry cloth to remove any sealant residues.

  1. Allow The Countertop To Dry 

Leave your countertop to dry for at least 24 hours before putting back the items you removed from there. Afterward, polish the surface after it has cured to give it a glossy look.

Other Helpful Tips

You should understand the different types of marble sealers. While there are differences between the sealers used for marble and other surfaces like concrete, the types are similar. 

Marble sealers come in different shades — and understanding the difference is crucial when shopping for a product. Water-based sealants and spray sealants are two common types of sealing materials you can buy.

Water-based sealants are a mixture of polymer molecules and water. The water usually evaporates after applying the sealant, leaving the polymer molecules to form a protective barrier on the marble.

These have a lower VOC rating, meaning the amount of Volatile Organic Compounds (VOCs) is low. VOCs are gases found in paints and other liquids, affecting the respiratory system — especially in low-ventilation areas.

The low VOC content is a good reason to recommend liquid sealants. But they do have a major disadvantage: their surface protection is limited. They don't bond well with marble surfaces as their spray-based counterparts, so you may need to re-seal the surface frequently.

Spray sealants comprise both solvent and polymer molecules and usually come in pressurized containers. The solvent evaporates after application, after which the polymer molecules bond to protect the surface.

These sealants are pretty effective in preserving marble counters, as they bond pretty well with natural stone. You should be careful to avoid exposure to VOCs while using spray sealants. The best idea is to use a respirator and throw open your kitchen windows to allow proper ventilation.

Another critical thing to know is that routine maintenance is essential

In between seals, try to remove any stains or etching that you find on the surface of the kitchen top. For coffee, lemon juice, and fruit juice stains, use a soft cloth paired with bleach to clean them. Tougher oil stains can be cleaned by running the surface with a mixture of baking powder and acetone.

You can preempt rapid breakdown of the seal by limiting liquid spills on your kitchen top. This is difficult, but try your best to keep acidic substances, such as lemon and vinegar, from getting to the surface.

Sealing your marble countertop is the best way to protect it from impurities and preserve its aesthetic appeal. Follow the steps listed in this article to avoid mistakes while applying sealant. With enough commitment, you'll find giving your kitchen top a seal easier than ever. 

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Andrew Wilson

Andrew Wilson is the founder of Contractor Advisorly. He has over 15+ years of professional experience as a home improvement and home construction contractor. Whether you're looking for DIY advice, tool recommendations or anything home improved-related, he's happy to share his insights.