How to Seal Cork Flooring
Cork is an environmentally friendly flooring material that’s soft underfoot and easy on the eyes. Cork has been used as flooring for decades, but its popularity has skyrocketed in recent years, largely due to its beauty and sustainability.
Cork flooring is made from the bark of the cork oak tree, which is native to the Mediterranean region. Every nine years or so, the bark is carefully cut away from the tree by hand. A protective inner layer of bark enables the tree to grow more bark to be harvested again the next decade.
Cork trees live for two to three hundred years and can produce useable cork for 150 years or more. Each tree will be harvested around 16 times during that time period. Cork forests are grown expressly for the purpose of harvesting cork. These forests are some of the most highly regulated in the world and are home to numerous wildlife species, including endangered animals.
Here, we discuss cork flooring and explain how–and when–to properly seal cork flooring to ensure it lasts a lifetime.
How is Cork Flooring Made?
Slabs of cork that have been stripped from the tree are cleaned and boiled. The cork is stripped from the rough outer surface of the bark and boiled again to soften it. It’s then ground into small particles and combined with a binder, which holds the particles together. Different types of binders produce different characteristics, such as flexibility and durability. The most commonly used binders include urea melamine, phenol formaldehyde and non-toxic, natural proteins. The cork mixture is pressed into molds and baked in special ovens to make tiles or planks for flooring.
Solid cork tiles are designed to be glued down to a sub-floor. Cork planks are made with a core of medium- or high-density fiberboard topped with a layer of cork. The planks snap together over the existing surface to create a “floating” floor.
Cork is highly renewable and sustainable. The manufacturing process for cork flooring produces almost no waste emissions, which means it has a very low impact on the environment. Additionally, cork is biodegradable once it has served its purpose.
The Pros and Cons of Cork Flooring
In addition to being one of the most eco-friendly flooring options available, cork flooring has a number of advantages over other types of flooring. Aside from needing periodic sealing, cork flooring is very low-maintenance and extremely durable, and it’s soft and comfortable under foot. Cork flooring deadens sound, and it’s a great thermal insulator. Other advantages of cork flooring include:
- Natural anti-microbial properties
- Natural insect resistance
- The ability to stain the floor
- The ability to refinish the floor to erase wear and tear and restore its original appearance
- Longevity, with an estimated life span of around 50 years
As with any other type of flooring, cork also has disadvantages. Sharp objects and furniture can puncture or scrape the soft cork, and skinny high heels can do a number on a cork floor. Heavy furniture may leave permanent dents in the cork, and liquids that aren’t wiped up immediately can stain it. High humidity can cause cork to curl or plump up, and direct sunlight may discolor the cork.
Why You Need to Seal Cork Flooring
It is important to seal cork flooring in order to protect it against moisture, fading, stains, and scratches. Sealing helps keep the cork flexible and prevents it from drying over time and shrinking at the seams.
Floating cork floors, which snap together, typically come with a factory finish of water-based polyurethane. Glue-down cork floors, which are generally installed in wet areas like the bathroom, must be refinished on-site after installation to seal the seams. All cork floors need to be recoated every three to seven years, depending on how much wear and tear the floor is subject to.
Water-based polyurethane sealers are durable and have lower VOC levels than oil-based polyurethanes. They also dry faster. For a standard cork floor installation in a dry, normal-traffic area, apply two to three coats of sealer. For installation in wet or heavy-traffic areas, apply three to four coats for optimal protection and waterproofing.
Sealing cork flooring makes maintenance a simple matter of sweeping daily and wiping the floor with a damp cloth or mop as needed.
How to Seal Your Cork Floors
Sealing a cork floor is a relatively easy DIY job, but it’s important to take your time and do it right. It’s also important to use a high quality sealer and applicator. Preparation is key, whether you’re sealing a brand-new, unsealed floor or you’re re-coating an existing cork floor.
1. Prepare the surface.
Inspect your cork floor for damage, such as uneven areas and rough spots. Sand these down with a drywall sander using 60-grit sandpaper. Sand the entire floor again with 100-grit sandpaper and then again with 150-grit sandpaper to create an even, smooth surface. Vacuum the floor thoroughly, then use a damp mop or cloth to remove fine dust. Vacuum thoroughly once more to be sure that the floor is completely free of dust and debris.
2. Stain the floor.
Staining your cork floor is optional. Stain changes the look of your floor, but if you like the natural cork color, sealing it in its natural state will enhance its beauty. If you stain the floor, use a water-based, high-quality stain. Open your windows to ventilate the room. Dip a clean cloth into the stain, and, working in small sections, apply it to the floor in circular motions. Allow the stain to dry before you seal the floor.
3. Seal the floor.
Pour some polyurethane into a paint tray. Using a 3/8-inch nap, microfiber roller, apply the sealer to the floor in one direction using long, even strokes and overlapping each section. Allow the first coat to dry thoroughly, around four to six hours. Lightly sand out any imperfections in the first coat, and if you want the best possible outcome, lightly sand the floor with 150-grit sandpaper, then vacuum, wipe, and vacuum again. Apply the second coat, and repeat the process. Don’t sand the final coat.
Follow the manufacturer’s recommendations for sealing products and tools, drying times, and cleanup.
Tips for Protecting and Maintaining Cork Floors
Sealing your cork floors will go a long way toward protecting them and bringing out their natural beauty. Regular maintenance will help keep them looking their best between re-coats. Here are some tips for maintaining your cork floors and protecting them from excessive wear and tear.
• Never use wax on a cork floor that’s been finished with polyurethane.
• Don’t use abrasive or harsh detergents on your floor. Try a nontoxic, mild detergent instead, or use vinegar and water.
• Sweep your floors daily with a soft-bristle broom to remove debris that can damage the finish.
• Use a damp sponge mop or microfiber cloth to clean your cork floors. Don’t soak the floor or apply cleaner directly to it.
• Avoid steam cleaners, which can damage the floor’s finish.
• Use protective pads under your furniture to prevent dents. Never drag furniture across the floor.
• Avoid walking on the floor in spiky heels, which can puncture or dent the cork.
• Keep pets’ claws trimmed to prevent scratches and gouges.
• Apply a hot, damp cloth to pull dents out of the cork.
• Use blinds to diffuse direct sunlight, which can cause fading.
When your floors are beginning to look dull, or when they become scratched and worn, it’s time to start thinking about a re-coat. With timely, proper sealing and routine maintenance, your cork floors will last a lifetime.