Last Updated: Mar 16, 2023
Wood is a beautiful material, but it's also vulnerable to damage from moisture, pests, and sunlight. Sealing your woodwork is an essential step in protecting it from these threats, but most conventional wood sealers contain harmful chemicals that can be hazardous to your health and the environment. One recent study found that around 80 percent of current wood finishes contain some sort of toxic volatile organic compounds (VOCs). In this guide, we'll introduce you to non-toxic wood sealers and help you make an informed decision about which one to choose.
Wood that is not treated or sealed correctly will not be as durable or permanent. When wood is not sealed or protected with a protective coating of polyurethane, urethane, sealants, or some other coating type, it readily absorbs liquid and moistures.
A spilled drink on your wood floor, driving rains that hit your wood siding, and even high humidity levels inside and outside your home can cause the wood to swell, thus leading to warps, cracks, and other imperfections. Furthermore, untreated wood is much more prone to be "infested" by termites, bugs, mildew, mold, and other "pests" that can quickly ruin your wood interior or exterior.
Waterproofing your wood is the most straightforward way to protect wood against rot, moisture, mold, and mildew. Though there are other natural ways to protect your wood from moisture (check out this Rise article on the Japanese Shou Sugi Ban method), most people rely on varnishes, sealants, and other similar products that are applied to the surface of the dry wood.
Any wood that is exposed to sunlight, rain, or excessive moisture should be waterproofed as this can help to prevent:
Waterproofing wood not only protects the wood from moisture (as its name implies) but also plays a vital role in protecting it from long-term exposure to the sun's UV rays.
Non-toxic wood sealers are natural or planet-friendly alternatives to conventional wood sealers that contain harmful chemicals. They're made from natural materials such as plant oils, beeswax, and water-based resins. Some non-toxic wood sealers may also have low levels of VOCs (volatile organic compounds), which are less harmful than conventional sealers.
The main reason to use non-toxic wood sealers is to protect your health and the environment. Traditional wood sealers contain chemicals such as formaldehyde, benzene, and toluene, which can be harmful to your health and the environment. These chemicals can cause respiratory problems, headaches, and even cancer. They can also contribute to air pollution and damage the ozone layer. Non-toxic wood sealers, on the other hand, are safe to use and environmentally friendly.
There are several types of non-toxic wood sealers available on the market. Each type has advantages and disadvantages, and the choice depends on your preferences and the type of woodwork you're sealing.
Water-based sealers are made from water-based resins and are the most environmentally friendly option. They're easy to apply, dry quickly, and don't emit harmful fumes. However, they may not be as durable as oil-based sealers and require more frequent reapplication.
Oil-based sealers are made from plant oils such as linseed or tung oil. They're durable and offer excellent protection against moisture and UV rays. However, they may emit harmful fumes during application and require longer drying times.
Wax-based sealers are made from natural waxes such as beeswax or carnauba wax. They offer good protection against moisture and are easy to apply. However, they may require more frequent reapplication and may not be as durable as other sealers.
Shellac-based sealers are made from natural shellac - a resin from the female lac bug. It's quick drying and provides a hard finish. It's easy to repair because old layers of shellac can be removed with alcohol. Shellac is prone to damage from hot pans and water, so it's not a top choice for kitchens and bathrooms.
Before treating wood with any sealant or waterproofing agent, it is important to ensure it is completely dried out. Wet wood, also called green wood, will continue to shrink as it loses water, which can negatively affect the sealant.
Fortunately, most of the wood products you purchase from lumber yards, home improvement stores, and similar commercial venues will have already been dried. If you are harvesting the wood on your property, allow the wood to dry properly before sanding and sealing the wood.
Some highly dense exotic woods are challenging to seal since the sealant has a harder time penetrating the wood's pores. In some cases, you might not need to seal exotic woods, especially for interiors where they will not be exposed to regular moisture or excessive traffic.
If looking to seal exotic wood, it's best to avoid using oil-based sealants, including polyurethane, the most common type of wood sealant. Oil-based sealants don't work well with many kinds of exotic wood because the chemical reaction that oil-based sealants cause in standard wood types does not happen with exotic wood types. Furthermore, clear sealants are usually preferred with exotic woods as they allow the natural textures, grains, and hues of the exotic wood to shine through.
Instead of using oil-based polyurethane sealants, consider using a few coats of de-waxed shellacs before putting on a top coat.
Homeowners can choose from several different wood sealant products, including stains or pigmentation. However, if you prefer the natural look of the wood, you can opt for clear sealant products.
Wood finishes of any type, including polyurethane, shellac, lacquer, wax, and varnish, will always alter the wood's appearance by accentuating the grain and texture of the wood. In general, sealants will also darken and deepen the natural color of the wood. If you want to avoid that glossy, shiny, amber-golden look, opting for oil-based polyurethane sealants or finishes is probably not a good idea.
To prepare wood for sealing, here is a quick checklist to help you with the process:
Once you have prepared your wood surface by sanding and cleaning, you will be ready to apply the sealant. Use high-quality brushes or rollers. If you are working with water-based polyurethane, do not stir too harshly, as this could lead to bubbles. Also, only put more sealant on the brush if necessary, and do firm, long strokes following the wood grain. Wait to apply a second coating or paint over the same area until it completely dries.
An exterior wood surface that sees heavy foot traffic and is directly exposed to sun and moisture should be resealed every one to three years. An interior surface that doesn't receive much foot traffic should only need to be resealed every ten to fifteen years.
The exact cost of wood sealant will depend on the quality of the product you purchase. Though it is possible to find relatively cheap wood sealants, these products are generally less durable and may off-gas dangerous VOCs into your home. For comparison's sake, a 5-gallon bucket of AFM Naturals Oil Wax Finish costs $570 here at Rise, enough to cover 1750 square feet.
Several non-toxic wood sealant products are on the market today. Some of the top brands include Vermont Natural Coatings, AFM Safecoat, nd Zinsser.
No matter what type of wood sealant option, finding a natural sealant is the best way to drastically reduce the dangerous VOC emissions off-gassing into your home.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.