Cork Flooring Buyer’s Guide
What it is, how it's made, and how to choose the right one for you
Cork flooring is perhaps one of Nature’s greenest miracle floors. Made from all-natural, renewable ingredients, cork floors are versatile, beautiful, and sustainable. They’re priced about the same as most hardwood floors; plus, natural cork flooring is DIY-friendly, easy to install, easy to maintain, and long-lasting.
The #1 reason people like cork flooring is because it feels soft but firm underfoot and is very quiet. The moment you step onto cork flooring, your knees and back relax. You’ll love the feel of cork flooring against your body and the quiet insulation it provides, whether you stand in the kitchen for hours, practice yoga in your rec room, living room, or bedroom, or just want to sit quietly in prayer or meditation.
Fact: Cork can last from 25-50 years in most applications.
Here are a few of its amazing attributes:
- Highly compressible and resilient
- Excellent thermal and acoustic insulator
- Naturally resistant to mold and mildew
- Warm to the touch
- Naturally resistant to fire and insects
- Hypoallergenic
- Stable in various temperatures
- Renewable resource
- Highly versatile with hundreds of uses
Cork comes from the bark of the cork oak tree, which grows in the forests of Mediterranean countries. It’s truly one of nature’s miracle products, renewing itself over and over again. The largest concentration of plantations is in Spain and Portugal, where the wine industry established them centuries ago. After 25-30 years, a new cork tree develops a thick bark that is about 2” thick. Skilled farmers with special tools carefully peel off about ½ of the bark. This doesn't hurt the tree; it grows back in 8-12 years, and the process starts all over again.
Fact: One cork oak tree yields 50 harvests over its useful life of 300-400 years. That supplies thousands of cork floors! Compare that to most hardwood flooring, which requires killing the trees to produce only a few floors, and you’ll see why cork is one of the most sustainable products available.
The cork bark is then cut into large uniform sheets 4’-5’ long x 2’-3’ wide. They’re carefully transported to a mill where thin layers are veneered off the surface. The outer bark layers are the densest, while the inner layers are softer and less dense.
The cork patterns you see on a cork floor come directly from the veneer's grain pattern. Just as oak grain differs from maple or walnut, cork has different grain patterns. These veneer patterns appear on the top layer of most cork floors.
Mother Nature designed the bark of the cork oak tree specifically to protect the tree throughout its lifespan. Not only is the bark inherently fire-retardant to protect the tree from forest fires, but it’s also resistant to extreme temperature changes prevailing in those regions, as well as resistant to more than 38 species of insects, including the termite, and to the development of microbes.
The properties of cork are derived naturally from the structure and chemical composition of the inner cells. For example, each cubic centimeter of cork's honeycomb structure contains between 30 and 40 million cells! It’s this unique cellular structure that gives cork its innate characteristics. Each cell contains suberin, a waxy substance that gives cork resistance to insects, mold, and mildew.
- Wine stoppers
- Flooring and wall coverings
- Noise deadening underlayment
- Clothing
- Furniture
- Thermal Insulation
- Exterior wall cladding
- Interior components for buses, trains, airplanes
- Bridges and highways
- Absorbents for oils
- Ping Pong rackets
- Hockey pucks, golf balls, baseballs, shuttlecocks
- Dartboards, kayaks and surfboards
- Soles for shoes and sandals
- Fishing bobbers and buoys
- Bee hives
In 1891, an American, John Smith, discovered that it was possible to produce agglomerated cork, opening a new range of applications such as wall tile, flooring, and underlayment. The agglomeration process involves gluing small pieces of cork together to form larger pieces in various shapes and sizes.
Cork floors have been popular in Europe since the turn of the 20th century and can be found in many prestigious locations such as the Library of Congress, the Mayo Clinic and Plummer Building, the offices of several Fortune 500 companies, several churches and museums, and the Frank Lloyd Wright Fallingwater residence.
Recently, with improved technology, an array of new patterns and colors have become available to meet the demands of today's design trends.
Cork flooring: floating planks and glue-down tiles
Originally, cork flooring was made in the form of a ¼” thick tile: 8” x 8” or 12” x 12”. These tiles were solid cork and glued to the subfloor with adhesive. They were also glued to walls for decoration. The finish was mainly oil and wax. Many people report that these original tiles are still going strong even after 75 years or more!
Since 2000, cork has advanced considerably as a resilient floor covering. Not only has the finish improved, but installation has also changed significantly. Today, most cork flooring comes in two basic forms: engineered floating floors and solid tiles.
Engineered floating floors - 3 layers
- Top layer - veneered cork (1/16" to 1/8")
- Middle layer - high-density fiberboard (1/4")
- Bottom layer - agglomerated cork (1/16")
Forms — two types
- Panels: 12” wide x 36” long – most common
- Squares: 12” x 12” These are always solid 1/4" thick and glued down
Floating floors versus glue-down tiles
Engineered floating cork floors have literally taken over the cork flooring market in the last 15 years for several good reasons:
- Easy DIY installation – no professionals needed
- No glue required – no nasty fumes
- Less subfloor preparation
- Faster installation
- More styles to choose from
- More stable – no edge curling
- Better finishes for easy maintenance
- No initial sealing required
Traditionally, cork was one natural color, light tan, with darker elements throughout. Today, cork flooring comes in numerous colors, achieved by staining the surface layer. These stains look nice and unique and can enhance any room's appearance. However, there are some drawbacks.
Here’s a look at all the current designs and colors.
Most notably, if the floor is deeply scratched or gouged, the natural cork color will show through and contrast with the surface color. This will require a special colored touch-up pen. Cork manufacturers typically don’t sell matching stains in a kit, so you have to find them on your own. Also, lighter colors such as white tend to show the seams more easily, which detracts from the overall look. These aren't serious drawbacks, but you should understand them up front before purchasing.
The natural cork colors (i.e., not stained) are by far the most popular because:
- The warm colors blend with most cabinetry and furniture
- They hide dirt extremely well
- They hide the seams extremely well
When you begin looking at all the intricate designs, it can be overwhelming. Small samples help, but you need a good imagination to envision how it’ll look in your home. Our 3D room visualizer is a very helpful tool to see how each color looks in any of your rooms. It’s easy and fun to scroll through all the colors.
Generally, we’ve found that color matters more than design because the design tends to blend into the color, especially from broad angles and in dim light. If a particular wild design excites you, then go for it. If you’re conservative, however, then pick something neutral and quiet, and you will be safe. It also depends on the lighting and what angle you’re viewing it from. In our experience, natural cork (unstained), in almost any style, works very well in most homes. We recommend ordering samples and testing them out
Many people are concerned about the finish of a cork floor. Regarding moisture, we have discussed how suberin naturally protects against moisture.
Cork is used in wine bottles and as fishing bobbers without becoming moldy. In his internationally famous 1930’s home, Fallingwater, Frank Lloyd Wright used cork on the floors, on the walls, and inside the showers of several bathrooms. There’s no mold anywhere on the cork.
However, for demanding applications such as kitchens and other high-traffic areas like entryways or hallways, you may want additional protection. In these cases, we recommend sealing the cork floor with a non-toxic polyurethane such as Vermont Natural Coatings PolyWhey Floor Finish or AFM Safecoat Polyureseal BP.
Regular maintenance requires only sweeping and damp mopping. If your floor starts to show signs of wear, a new coat of polyurethane will rejuvenate the floor. A properly maintained cork floor will last for decades.
Cork has also become a popular underlayment to reduce sound and to improve thermal efficiency. Cork underlayment generally comes in 1/8" to 1/4" thick rolls. Cork underlayment has become the product of choice beneath ceramic tile, hardwood flooring, carpeting, and other solid surface floors, mainly in apartments and condos.
What to look for in a cork floor
Cork flooring is one of the best green floors no matter who makes it, right? Wrong. While cork flooring may look similar from one manufacturer to another, the differences usually show up months later in performance, indoor air quality, and maintenance.
Let’s take a deeper look into how cork is manufactured to understand some of these differences.
Density + resiliency = durability
For the top layer, manufacturers use a cork veneer taken from the outside portion of the cork bark because it’s older and denser than the inner portion, which is younger and softer
Manufacturers grind up the inner portion of the cork bark and use it on the bottom of the plank as a built-in underlayment.
Densities are measurable and labeled by some manufacturers — the higher the density, the better. There may not appear to be big differences, but careful examination and testing will reveal some cork is softer and less resilient than others, while some are much firmer and denser, providing a more durable product.
It’s well known that cork has a great ‘memory’ or impact resistance. Try digging your fingernails into some cork, and you can easily dent it; but after about an hour or so, most of the dent will have disappeared. The denser the cork, the more suberin cells, and therefore the better the performance.
The overall thickness of both the top and bottom layers also varies. Hold two pieces of cork flooring back to back, and you will easily see these variations. Thicker cork on the top and bottom is preferred, but it does not always mean it’s denser. You have to test them yourself or check the specs.
Adhesive is used between each cork layer and between the backing granules. Because most cork comes from Europe, adhesive and emissions standards are usually much higher than in the US. Most manufacturers exceed E0 and CARB 2 standards for urea formaldehyde; however, not all are third-party certified. You have to check, since everyone now claims their product has “no added formaldehyde.”
China also competes in the cork flooring market. Unfortunately, the standards there are questionable. To be sure you’re getting safe products, insist on independent certifications to verify a manufacturer’s claims.
Unlike cork tiles, which are solid cork 12” x 12”, 95% of all cork floating floors incorporate a high-density fiberboard (HDF) in the middle section of the panel. Some have added urea formaldehyde, and some don’t. Some are made from recycled, FSC-certified wood fibers, and some are not. FSC stands for Forest Stewardship Council, an independent worldwide organization that certifies sustainable harvesting, social equity, and environmental stewardship. We recommend HDF that is FSC-certified, has no added urea formaldehyde, is exterior grade, and is impregnated with wax around the perimeter.
Here is where some major differences may appear. For hundreds of years, natural linseed oils and beeswax worked very well as a finish on cork tile flooring. If you visit older courthouses or libraries, you’ll find oil-waxed cork tile flooring still going strong.
While most new finishes are UV-cured in the factory, some may still off-gas for weeks or months after installation. Most manufacturers do not disclose this information in their Safety Data Sheets (SDS).
Commercial finishes are now available for cork; they are extremely tough and can extend the life of the cork for years before recoating is necessary. We recommend: Vermont Natural Coatings PolyWhey Floor Finish or AFM Safecoat Polyureseal BP.
Note: If you are refinishing an older cork tile floor, it must be free of oil and wax before applying a water-based coating. You can recoat floating floors with a polyurethane finish, but you must lightly sand them first to rough up the surface and provide some tooth for good adhesion.
If you’re chemically sensitive or have allergies, test a sample first. For everyone, including the chemically sensitive, please learn how to test a non-toxic product for tolerance.
Most residential warranties cover structural integrity, meaning the top, middle, and bottom layers won’t delaminate. Some warranties also include the finish on the top layer, although they never cover normal wear and tear. They typically cover finish defects such as delamination, pitting, or a rough feel. Residential warranties are usually lifetime on the structure and 10-25 years on the finish. Commercial warranties are usually shorter, around 5-10 years, but new finishes can come with longer warranties, up to 15 years.
Keep in mind, if you have large dogs or kids with skateboards, a residential or a commercial warranty will not cover abuse. In general, you can repair deep scratches and gouges with wood putty, and the natural color variations hide them well. The same holds for hiding dirt.
Bottom line: choose the best warranty, but understand that all flooring warranties cover only manufacturing defects and never pay for removal or installation costs unless you can prove manufacturer negligence.
Cork tiles (made of solid 1/4” thick cork) are glued to a perfectly smooth level subfloor. However, cork “floating floors” (planks, squares, large or narrow tiles) can be installed on top of most wood or concrete subfloors. You can even install them over existing vinyl or laminate flooring.
(Please refer to the manufacturer’s installation guidelines)
Cork floating flooring edges are designed to click together; no glue is required. With only a few tools required, installation is relatively easy for most do-it-yourselfers. Most rooms can be completed within a few hours.
Consider a professional if:
- you're not handy with tools
- you want a flawless looking floor
- your subfloors are uneven and need prep work
- you don't have the time
- your mother-in-law or father-in-law is moving in next week
- your spouse doesn’t exactly love your carpentry
Consider doing it yourself if:
- you have some basic skills and own some tools
- your subfloors are relatively even
- you have time to do this properly
- you need to save money
- your spouse is not fussy
Where is cork flooring installed?
Cork is commonly used in kitchens, bathrooms, rec rooms, dens, and living rooms or bathrooms. The more cork you use, the better it looks. Large areas of cork really look much better than a small area here or there. This is true of most flooring.
What about basements and bathrooms?
Cork and water get along very well, which is why it’s used in wine bottles and on fishing bobbers. However, the finishes and adhesives aren't designed to stay underwater for long periods. Most cork floating floors have a high-density fiberboard core impregnated with wax to prevent moisture absorption. Make sure your cork flooring has this feature.
If you have young children, we don’t recommend using cork in their bathroom. If your basement floods every so often, we don’t recommend that either. However, dry basements are fine, and so are bathrooms where constant moisture is not an issue and good ventilation is available.
What about radiant-heated floors?
Yes, cork works fine here too. Remember, radiant heat is infrared, which transfers through just about any material, including concrete, wood, glass, metal, insulation, etc. Cork is a thermal insulator, a good one, but it doesn't stop infrared heat from penetrating. We have worked with dozens of customers with radiant-heated floors that all say, “No problem, it works fine.”
Which style or pattern to choose?
Cork comes in busy patterns and quiet patterns. Depending upon your taste and the style of your home or office, don’t be afraid to experiment with some wilder ones as they rarely look that wild after installed on the floor. Patterns is a misnomer as they are never repeating, but always random.
Regarding styles such as floating plank vs squares vs large tiles or narrow tiles: Standard planks (12” x 36”) or squares (12” x 12”) have a square edge detail that creates a more uniform, smooth floor. Large and narrow tiles have beveled edges and create a more traditional look. You have to see several pieces together to really get the feel, but they do have their place.
How is cork flooring maintained?
Caring for cork flooring is similar to caring for hardwood, linoleum, or bamboo flooring. Regular dusting and damp mopping are all that’s required to keep it in good shape. Most manufacturers warn customers not to flood it with water, as repeated flooding can cause the edges to swell. As with all flooring, avoid harsh cleaning chemicals and excessive water. If maintained properly, cork flooring should last as long as your home. Here’s a link to our floor cleaners.
If repairs are needed, standard wood putty works for most deep scratches or gouges. In high-traffic areas, you may want to apply a couple of coats of polyurethane to extend the life of the finish.
How much extra should I order?
In general, 10% extra. This depends upon the size and shape of the room(s). Large square rooms with no closets will have the least amount of waste. Add closets, hallways, L-shaped areas, or curved or angled walls, and include 10% extra in your estimate.
While cost may be a factor, an extra box or two is insurance. This is true for all flooring. As retailers since 1991, we often receive inquiries for old, outdated flooring designs or patterns for a new addition or a damaged area. Customers spend hours searching high and low for a few extra planks that should have been purchased with the initial order if the color or style has been discontinued.
Go to the Green Building Supply Learning Center to browse our entire collection of articles, FAQs, and white papers for every product. Our article How to Buy a Green Floor describes 7 common mistakes and how to avoid them.
Need help measuring or making decisions? Please CALL US at 1-800-405-0222 or email customerservice@greenbuildingsupply.com and we'll be happy to help you choose the right floor for your application and budget.
Beautiful, soft, warm, non-toxic, renewable, insulating, and sustainable, cork is clearly one of the best green floors available. Give it a try in one room and you'll see why.
