Non Toxic Wood Flooring For Your Home – Which Wood Flooring Is Non Toxic?

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Non Toxic Wood Floors – Which wood flooring is non toxic?

My husband and I are having our hardwood floor replaced for our home soon. Therefore, I wanted to make sure we are choosing the right materials and if there is anything we needed to know. We have a toddler and a dog so we wanted to minimize toxic volatile compounds (VOCs) from the newly replaced floor. In this post, I share with you how wood flooring can be toxic and what non toxic wood flooring options are available.

Different Types Of Wood Flooring And How They Can Be Toxic

Solid Hardwood

Solid hardwood is made of solid hardwood only. It has many advantages. Solid wood is very durable so it is ideal for any living areas of the house such as living room or bedroom. It could last a lifetime if it is maintained right. Also, it can be sanded and refinished many times when there are damages, wear and tear. It also adds value to your home when you resell your home.  Also, it is the most non toxic wood flooring option you can pick. Not only it doesn’t contain glue since it is made of solid wood only but also installation of solid hardwood doesn’t require glue. Solid hardwood can be installed by using nails. However, if you live in a condominium with concrete subfloor, you will most likely need an engineered floor since nailing method can’t be used. Solid wood flooring should be avoided in moist areas such as bathroom or basement since it doesn’t deal with moisture well. It is also one of the most expensive wood flooring options.

There are many types of hardwood you can choose from.  Hardwood can get dents or damage. Although all wood can get scratched regardless of hardness, weaker wood is more vulnerable. Brazilian Cherry, Brazilian Walnut or Santos Mahogany is one of the hardest hardwoods available. They are the strongest and are extremely durable. Hickory, Sapele or Maple is one of the harder hardwoods. They don’t scratch easily and even resist heavy impacts well. (great for home with children or pets)  Oak is one of the most popular hardwood species but it can get scratched easily. Therefore, it should be used with furniture pads. Oak, Beech or Ash are in the mid range for hardness. American  Cherry or walnut is one of the softer wood species. Wood species all come with hardness rating (high: 2000 Mid: 1300 Low: 1000). The hardness of the hardwood is important when choosing hardwood species. However, hardness/Janka rating is not the be-all end all of durability.  Each species has different colors, textures and characters. Hardness of the wood can be a point to help decide what floor to purchase. According to Ryan Adamson from Tesoro Woods, oak, for example, has strong grain patterns. They effectively “hide” most moderate scratches. Species like Maple are “harder” but because of its mild to almost non existent grain pattern scratches are highly visible. Durability of the hardwood floor also depends on type of finish and how much traffic the floor has, how well the floor is maintained, etc. 

If sustainability is important to you when choosing solid hardwood floors, select solid hardwood that  are FSC certified.  In order to be given Forest Stewardship Council (FSC) certification, a forest must be managed in an environmentally appropriate, socially beneficial and economically viable manner. FSC also tracks the timber through every stage in the supply chain from the forest to the final user. This certification ensures that wood is harvested sustainably and also not illegally logged.

Solid hardwood is a natural material and it is non toxic.  However, its protective finish can be toxic. After installation of hardwood, hardwood flooring is given a protective finish. A protective finish can emit volatile organic compounds (VOCs) when it is being applied and while it is drying and curing. Even long after this finish has dried, smaller amounts of VOCs continue to off-gas into the air. The U.S. Green Building Council reports oil-based finishes can release VOCs for months or even years.  Some lower-VOC, water-based finishes largely finish off-gass within a few days. However, they can still off-gass small amount of VOCs after. One of the very popular finish choices is oil-based polyurethane finish. Although oil-based polyurethane is very durable, it has a high VOCs and a strong odor when applied. It also takes a long time to dry (about 8 to 10 hrs) between coats. Acid-cured finish is extremely durable but has very high VOC content.  Water-based polyurethane finish, on the other hand, has lower VOCs and less odor. It also has a faster drying time (about 2-4 hrs) between coats. However, it requires more coats than oil-based finish. Non toxic finish options include penetrating oil sealers (natural oil sealers, made from linseed oil and pure tung oil) or Shellac which has low VOC content and mild odor. You can also choose pre-finished hardwood floors instead of having the floors finished on-site. Pre-finished hardwood is already sanded and sealed at the factory. Therefore, you don’t have to wait for a finish to dry and there are no VOCs or odors from stains and finishes. Pre-finished solid wood with a natural oil finish is available but can be very difficult to find. Urethane finish is widely used for most pre-finished hard floors. Therefore, if you can’t find pre-finished solid hardwood with natural oil sealers or shellac, you may want to purchase solid hardwood flooring unfinished and have it finished on-site. 

If you would like to find out more about non toxic solid wood flooring, please read my next post, ‘How You Can Choose The Most Non Toxic Solid Hardwood Flooring.’

Engineered Hardwood

Engineered Hardwood is usually made of multiple layers of a composite material such as plywood in the core and a thin veneer of natural wood on top. Only the top layer is real wood.  Therefore, engineered hardwood is not as natural as solid hardwood and it can emit toxic chemical called formaldehyde. Formaldehyde is actually a naturally occurring chemical in solid hardwood and solid hardwood releases only a trace amount of formaldehyde. (0.002 ppm for beech wood and 0.009 ppm for green oak for example). Engineered hardwood, on the other hand, can emit  higher amount of formaldehyde.  Formaldehyde above safe levels can irritate eyes, nose and throat and can cause many symptoms such as burning sensation of the eyes, wheezing, difficulty in breathing, fatigue, headache, and nausea.  It can also trigger asthma symptoms in those with asthma.  In addition, it is a known human carcinogen.  According to the International Agency for Research on Cancer (IARC), a division of World Health Organization (WHO), formaldehyde is undetectable by smell at concentrations of less than 0.1 ppm. At concentrations between 0.1 ppm and 0.5 ppm, it is detectable by smell, with some sensitive individuals and they can experience slight irritation to the eyes, nose and throat.  At concentrations from 0.5 to 1.0 ppm, most people experience irritation of the eyes, nose and throat. At concentrations above 1.0 ppm, exposure to formaldehyde can result extreme discomfort.

Engineered hardwood contain plywood which is thin layers of wooden board glued together. Depending on what type of glue was used for the engineered wood and also composite wood parts, the formaldehyde emission level will differ. For engineered wood in general commonly use phenol-formaldehyde (PF) or urea-formaldehyde (UF) adhesives. Urea-formaldehyde (UF) products emits 100 times more formaldehyde than the natural wood whereas PF-glued products typically emit 10 times the formaldehyde outgassed by natural wood. Urea-formaldehyde offer cheap cost for manufacturers but it has very high formaldehyde emission. Therefore, any plywood that is made with Urea-formaldehyde adhesives should be avoided.  However, Quality floor from a known, respected brand don’t have high formaldehyde issue.  Actually, engineered hardwood floors are commonly manufactured using a phenol-formaldehyde resins these days. (However, keep in mind phenol-formaldehyde resins still contains formaldehyde and emits formaldehyde ten times more than solid hardwood.)

There are several things you can look for when choosing a safer engineered hardwood flooring.

CARB 2 – Some engineered hardwood uses composite wood core that is CARB 2 certified. CARB 2 limits formaldehyde emission level from composite wood products at 0.05ppm. If engineered wood flooring is constructed like plywood or contains composite wood products such as hardwood plywood or Heavy Density Fiberboard (HDF), and is sold or supplied to California, it is required to be CARB Phase 2 compliant and labeled. CARB offers manufacturers who use no-added formaldehyde (NAF) or ultra-low-emitting formaldehyde resins (ULEF) resins, exemption from CARB requirements. NAF has no added formaldehyde and ULEF has really low formaldehyde emission that is below Phase 2 emission standards. You can lower formaldehyde emission by choosing engineered hardwood with these glues. CARB requires the product to have a CARB compliant label. However, this regulation is more about utilizing CARB 2 certified cores, not the whole flooring. Keep in mind that engineered hardwood can be constructed in different styles. CARB 2 or TSCA Title VI only applies to engineered hardwood that has composite core.  Some engineered wood such as 3-ply core engineered wood is not subject to CARB 2 requirements.

TSCA Title VI – Environmental Protection Agency (EPA) requires all 50 states to have formaldehyde emission limit of 0.05 ppm for all regulated composite wood products, and finished goods containing composite wood products.  According to the Environmental Protection Agency (EPA), all regulated composite wood products, and finished goods containing composite wood products, manufactured in or imported into the United States after March 22, 2019 are required to be certified as compliant with the TSCA Title VI or the California Air Resources Board (CARB), Airborne Toxic Control Measures (ATCM) Phase II emission standards by a third-party certifier approved by CARB and recognized by EPA. EPA doesn’t require a TSCA compliant label if the product has a small amount of composite wood under 144 square inches.

CA Section 01350 – This is a voluntary certification which tests for emissions from thousands of other chemicals in addition to formaldehyde. It tests emissions from the whole product and it can be also applied to all types of flooring products including floors without composite core.  Some engineered hardwood floors have this label to indicate floor’s ability to contribute to good indoor air quality.

LEED – Some engineered wood is also qualified for LEED credits. LEED, or Leadership in Energy and Environmental Design, is a green building rating system which provides a framework to create healthy, highly efficient and cost-saving green buildings including residential and commercial properties. LEED certification for home not only makes a home healthier, safer and more valuable but also saves more energy which can save you money.  LEED has many categories and not all categories represent low VOCs. Therefore, see under which category, the engineered wood can get credits if it is LEED qualified for credits.  If engineered wood is qualified for LEED credits for low emitting materials under Indoor Environmental Quality category, that would be one way to find non toxic engineered wood.

GREENGUARD – GreenGuard certifies products or materials designed for use in indoor spaces to meet chemical emission limits for indoor air quality. It tests emission levels for over 360 volatile organic compounds (VOCs), plus a limit on the total of all chemical emissions combined (TVOC). GreenGuard Gold has stricter criteria for sensitive individuals such as elderly and children.  Some engineered hardwood is GreenGuard Gold Certified. 

FloorScore – You will often see FloorScore certification on engineered hardwood. This is a voluntary indoor air quality certification for finished flooring products. Finished flooring product is tested for 35 individual VOC emissions (including formaldehyde) specified by CA Section 01350.

Engineered wood is actually less likely to get damaged when exposed to moisture. Therefore, it can be used in basements. (It can also be used in other living area of the house just like solid wood.) Solid hardwood can swell, contract or shift when exposed to moisture so it is not used in basement area.  However, since only a part of the wood is real wood, it is less expensive and less durable than solid wood. A real wood surface of engineered hardwood flooring can be sanded and refinished at limited times (maybe once or twice during its life time) to remove damage. Engineered wood can be installed with glue, float or staple. If glues are used, be sure to use Zero-VOC adhesives since glues can emit harmful Volatile Organic Compounds (VOCs).

Reclaimed Wood

Reclaimed wood is wood previously used for other wooden projects such as old barns, factories, warehouses or pallets. It is re-used for furniture, cabinetry or flooring.  Reclaimed wood can add history and character to your home. It is also a sustainable wood flooring choice since new trees do not have to be cut, processed and transported. This process consumes a lot of energy and causes impact to the environment. Reclaimed wood is also very strong and durable since old growth wood comes from trees that are grew slowly due to limited light and competition from the other trees. It has the tight growth rings and heartwood (which forms as the tree ages) and make it more strong, durable and rot resistant than new wood. Also, it is considered recycled content, therefore, it can qualify for Leadership in Energy and Environmental Design^® (LEED) credits for certification, a rating system that is recognized internationally for certifying green buildings.

Despite all of these positive things reclaimed wood have, reclaimed wood can have molds, chemicals, or insects. For example, grocery pallets could have bacteria from spilled food. Barns can have bacterias from animal feces. Wood from 1978 or earlier can have lead paint.  Wood exposed to water can have mold and mildew. Railroad ties and trestles are often treated with creosote or pentachlorophenol.  Creosote and pentachlorophenol are a probable human carcinogen. In addition, we don’t know what the reclaimed wood might have been previously treated with. Reclaimed wood may have been treated with insecticides, volatile organic compounds, preservatives, lead or adhesives by companies. Therefore, it can have volatile organic compounds from various chemicals and treatments and we wouldn’t know about it.

You can find out if the reclaimed wood is safe by finding out where the reclaimed wood is sourced from and test it. However, that is not easy for many people. One way to minimize the volatile organic compounds is to get reclaimed wood that is GreenGuard Gold or CA Section 01350 certified for low chemical emissions. Reclaimed wood can be nailed down and glued for installation. Choose a nailing method to minimize VOCs from adhesives. You can also select to use a water-based, Green Seal 11- certified finish or non toxic natural floor oil finish.

Laminate

Laminate flooring is a much economical option compared to the hard wood or engineered wood flooring and it simulates the look of real wood or stone. It doesn’t contain any natural wood or stone.  It is made of four layers: bottom layer, core layer, decorative layer and wear layer. The bottom layer is often made of melamine (plastic material) and it is used as a barrier against moisture.  The core layer is made of compressed wood fibreboard. The decorative layer has the printed paper with a photographic image of wood or stone to simulate real wood or stone. Top layer is a clear layer made of aluminum oxide to protect against stains, scratching or fading. This layer can be made of melamine, aluminum oxide, or sometimes combination of the two.

As you can see in the material descriptions of a laminate plank layer, a laminate plank is not made of natural materials.  Pressed wood products such as Medium Density Fibreboard (MDF) or High Density Fibreboard (HDF) are made of wood chips, fibres, strands, strips or veneers. These wood particles are often bound together by glue that contains formaldehyde. MDF or HDF usually uses urea formaldehyde (UF) glue which emits high levels of formaldehyde. Melamine resins (also called melamine formaldehyde) on the top layer of the laminate flooring contain and emit formaldehyde into the air which we can inhale. Melamine resins (plastic material) are made by combining formaldehyde and other agents to melamine.  Aluminum-oxide which is often used on the top layer can be harmful when inhaled. You can be exposed to the aluminum-oxide particles when floor is sanded. Inhaling aluminum oxide can also irritate the nose, throat and the lungs causing coughing, wheezing and/or shortness of breath.

Laminate flooring planks can be either glued together or snapped together depending on the type you buy. If the laminate flooring is installed using glue, then formaldehyde emission is a concern. However, laminate flooring can be installed without using glue. Therefore, you can reduce formaldehyde exposure that way. However, overall, laminate flooring is toxic because of the materials and glue used in the laminate flooring planks.

Bamboo

Bamboo is a highly renewable resource and it can be re-harvested every a few years. It is actually a grass, therefore, we don’t have to wait for a long time to harvest like we do with trees. It also regenerates quickly without planting a new crop of bamboo. It is also known as an eco-friendly material since it doesn’t need pesticides to grow. Bamboo has gained popularity as a sustainable material nowadays. However, despite the green side of bamboo, bamboo has been also criticized that it is actually not a green material. Bamboo comes mostly from countries in Asia such as China. To keep up with popular demands of bamboo, forests are cut down to plant and grow bamboo for commercial purposes. Farmers are also increasingly using fertilizers and pesticides to grow bamboo more and faster.

In the production of bamboo floor planks, bamboo stalks are cut into strips, purified, sorted, dried then glued together and pressed under high pressure to achieve the strength and durability.  During this process, Urea formaldehyde glue which emits 100 times more formaldehyde than the natural wood, can be used. Traditionally, it has been used in most engineered and hardwood bamboo flooring. Some high quality bamboo doesn’t use this glue now but cheaper bamboo may still have this issue. If you want to reduce formaldehyde exposure from bamboo flooring, choose solid strand woven bamboo floors.  Most Solid strand woven bamboo floors use phenol-formaldehyde resins which typically emit only 10 times more formaldehyde than the natural wood. They also use very little adhesive compared to bamboo planks that are made using vertical construction method (which are glued and pressed).

Also, if bamboo flooring has a multilayer hardwood plywood platform, it will be subject to meet CARB Phase II requirements (solid bamboo flooring, solid strand bamboo flooring and bamboo flooring that has solid lumber core are not subject to CARB). If you go for engineered bamboo flooring, look for bamboo flooring materials that meet CARB Phase II standard which limits formaldehyde level. (which sets its levels at 0.05ppm) However, keep in mind CARB Phase II is about the composite wood platform material contained in the bamboo flooring, not the whole flooring.  You can also find bamboo that meets No Added Urea Formaldehyde (NAUF) standard for low formaldehyde emission. In addition, GreenGuard Gold, CA Section 01350 or  FloorScore certified bamboo flooring has low volatile organic compound (VOC) emission including formaldehyde.

You can get darker color of bamboo by a process called carbonization. However, this process is done by pressure heating the bamboo and it weakens the bamboo. Carbonized bamboo has decreased strength, therefore it is less durable.

Final Thoughts

Most concerning issue with wood flooring is emission of volatile organic compounds (VOCs) including a known human carcinogen, formaldehyde. You can minimize VOCs by choosing a material, glue, finish or installation method that has the least of amount of harmful chemicals. After researching different materials, I feel that solid wood is the most non toxic option. It doesn’t contain any glue and also doesn’t require glue for installation. Although it is more expensive wood flooring option, it can add high value to your home. However, keep in mind not all places can have a solid hardwood flooring. Since it has to be nailed down, you would have to go for another flooring option such as engineered wood flooring for a place like a condominium which has concrete sub floor. (unless you can put another subfloor)

However, even if you choose other materials, you can still lower emission of VOCs by selecting materials that use water-based, non toxic glues such as no-added formaldehyde (NAF), ultra-low emitting formaldehyde (ULEF), no added urea formaldehyde (NAUF) glue. Avoid urea formaldehyde adhesives. For the finish of wood floors, natural oil sealers or shellac will be most-non toxic and this is can be easily done with unfinished hardwood floors. There are not that many pre-finished solid hardwood with natural oil sealers available. If the type of flooring has an installation method by nailing the planks to the floor, choose the nailing method instead of gluing the planks to install. If nailing can’t be done, floating method  will use less glue than glueing the whole floor. You can reduce VOCs by limiting the use of glue. If you must use glue, choose water-based, non toxic glues.

Product certifications can also help you choose a better wood flooring product. Seek after Forest Stewardship Council (FSC) certification for sustainably harvested wood or bamboo. Composite wood products such as medium density fiberboard (MDF), hardwood plywood (HWPW), particleboard (PB) with a California Air Resources Board’s Phase 2 (CARB 2) label will have composite wood core that has low level of formaldehyde emission.  If you also purchase engineered wood (containing composite wood) manufactured or imported after Mar 22, 2019, it has to be TSCA Title VI or CARB 2 certified for low formaldehyde emission.  CA Section 01350 tests for emissions from thousands of other chemicals in addition to formaldehyde for the whole flooring and for all types of floors.  GREENGUARD GOLD Certification or FloorScore also limits certain VOC emission from a product. In addition, LEED (Leadership in Energy and Environmental Design) gives credits to low emitting materials under Indoor Environmental Quality category to be qualified for LEED certification and these materials will have low VOC emission. All of these certifications and labels can help you reduce VOCs from wood flooring. I am looking forward to go shopping for hardwood floors. I will include some non toxic wood flooring products in my future post.

If you would like to find out more about non toxic solid wood flooring, please read my next post, ‘How You Can Choose The Most Non Toxic Solid Hardwood Flooring.’

If you are interested in non toxic engineered hardwood flooring, please read my post, ‘How You Can Choose Non Toxic Engineered Hardwood Flooring‘.

If you would like to find out about non toxic wood flooring options, please read my post, ‘Non Toxic Wood Flooring For Your Home – Which Wood Flooring Is Non Toxic?‘

If you would like to find more about ceramic or porcelain tile flooring, please read my post, ‘Ceramic or Porcelain Tile Flooring – Things to Consider When Choosing Ceramic or Porcelain Tile.’

If you are interested in non toxic mattresses, please read my post ‘Non Toxic Mattress Guide – Chemical-Free, Organic Mattress‘.

For non toxic sofa companies that you can shop from, please read my next post, ‘Non Toxic Sofa Guide – Which Sofa Brand Is Non Toxic?‘

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