Untreated wood, whether air- or kiln-dried, requires protection to prevent moisture penetration. Stains, paints, sealants, and natural wood treatments are how to protect untreated wood further from rot and UV exposure while accentuating its inherent beauty.
These protection methods are tailored to specific wood species, prevailing environmental conditions, and desired visual outcomes for outdoor applications. Combined with proper surface preparation and application techniques, these protective products ensure that untreated wood remains resilient and attractive in outdoor environments.
Paint
Untreated wood is popular for its natural aesthetic and durability in outdoor projects, but it is vulnerable to moisture, pests, and weathering. Fortunately, outdoor paint provides a protective barrier against harsh elements that can extend the lifespan of your wooden projects and ensure they look their best. This article examines how outdoor paint protects untreated wood, and offers tips for selecting the right paint, application technique, and regular maintenance to preserve your wood pieces.
Moisture is the biggest contributor to rot, and paint can help prevent moisture from damaging your wood. When painting, use a high-quality exterior paint that is specifically designed for use on wood. You can also use a waterproofing sealant to further protect your wood from moisture and rotting. Be sure to follow the sealer manufacturer’s guidelines for the application and drying process.
UV exposure is another common cause of deterioration in untreated wood for outdoor using. The harmful UV rays can break down the wood’s lignin, leading to discoloration, surface degradation, and structural weakness. Outdoor paint that includes UV inhibitors can protect your wood for outdoor furniture from fading and sun damage.
Before you paint, sand the surface of your untreated wood to smooth it out and remove gouges, splinters, and dirt. Once the wood is sanded, apply a coat of high-quality primer that is designed for your specific wood type. Once the primer is dry, you can begin applying your paint. You can use a brush, roller, or sprayer to apply the paint.
Once you have applied your paint, it is important to inspect the wood regularly for any deterioration or cracking. Address these issues promptly to maintain the integrity of your painted wood and maximize its protective capabilities.
It is also important to inspect your wood regularly for any signs of mold or mildew. These conditions can cause rot in untreated wood, so addressing them quickly is essential to preventing further damage. Wood rot can be caused by several factors, such as excess moisture, poor construction, and insect infestations. However, paint can provide an effective layer of protection for treating wood and keep the fungus from getting into the inner structure of your wood.
Waterproofing Sealants
When it comes to protecting untreated wood, there is a wide variety of products available. Whether they are referred to as wood sealant, stain, oil, or waterproof, they are all designed to protect the wood from moisture damage. Some are clear while others have color options. Some require longer drying and curing times than others to ensure they are ready to withstand moisture exposure.
There are three oils typically used in wood waterproofing: linseed, walnut, and tung. Linseed oil is a traditional favorite because it’s easy to apply with a brush and it doesn’t contain metal drying agents, which makes it safer for outdoor use and on some species of wood. It is also the safest option if you have nut allergies. It is important to note that linseed oil will not last as long as some other waterproofing products. It will need to be reapplied regularly to continue to provide protection.
Waterproofing with oil creates a film on the surface of the wood that stops moisture from penetrating the grain. However, this coating can deteriorate over time and leave the wood vulnerable to moisture damage once again. Depending on the type of oil, it may take up to four coats to create a protective barrier.
Before applying a waterproofing product, the surface should be sanded to remove any dirt or finish that might prevent the waterproofing from soaking in. The sanding should be light so that the wood doesn’t become rough or scratchy. After sanding, the surface should be dusted with a lint-free cloth to remove any dust nibs. Once the surface is clean, apply the first coat of waterproofing using a brush. Allow it to dry for a day or so by the manufacturer’s instructions.
To determine if the coating is providing sufficient waterproofing pressure-treated wood, perform the splash test. Pour a small amount of water onto the surface. If it soaks in and darkens the wood, the surface needs to be treated again. If it beads, rolls off, or sits on the surface, it is protected.
Natural Oils and Waxes
For individuals seeking a more organic approach to wood protection, natural oils, and waxes offer nourishment while creating moisture-repellent barriers. Linseed oil, tung oil, and other plant-based oils penetrate the surface of untreated wood, enriching its natural tones and preventing rot, mildew, and other harmful environmental factors. Combined with protective finishes like beeswax and carnauba wax, these oils provide extra protection and additional weather resistance for enduring beauty and structural integrity.
With a wide variety of natural and synthetic options available, individuals can tailor their choice of oil to suit the environment where their untreated wood will be used and the aesthetic outcome they desire. Many of these products are available in both clear and tinted formulations, allowing individuals to select a finish that complements other elements of their décor without detracting from the original appearance of the wood.
Natural oils also create a flexible barrier that allows the wood to expand and contract with fluctuations in outdoor temperature and humidity, helping to avoid cracking or warping. In addition, these oils are safe for direct human contact, making them a great choice for surfaces such as all wooden furniture, tables, and worktops where regular spillages may occur.
Another natural option for protecting untreated wood is boiled linseed oil, which is commonly applied to interior hardwood floors and kitchen worktops. With a quicker drying time than other oil finishes, boiled linseed oil provides a protective coating against liquid spillages while adding a beautiful sheen to wood surfaces. It is important to note that while mineral oils are a relatively inexpensive treatment option, they do not offer long-term protection for wood and need to be reapplied regularly.
Another popular wood finish is hard wax oil, which offers a durable and protective seal for wooden surfaces. Made from a blend of sustainable raw materials, including sunflower oil, jojoba oil, beeswax, and carnauba, these products repel water, enhance the beauty of the wood, and protect it for years. Like varnish and other oils, they can be applied by hand or with a brush and are suitable for use on furniture, doors, and window sills. However, it is important to note that unlike varnishes and other finishes, waxes will eventually melt and need to be reapplied.
Wood Preservatives
Wood is an attractive and versatile building material, but without protection, it can quickly degrade. Untreated wood is susceptible to insects, fungi, and moisture. To avoid rot and decay, use preservatives to treat outdoor wood. A variety of wood preservers are available, including stains and varnishes. Wood preservatives protect exterior wood against weathering and provide a finished look.
Fungus thrives in damp wood and soil and is one of the leading causes of rot. Keeping wood out of direct sunlight helps prevent moisture and fungus from damaging wood. Fungus also robs wood of its natural chemicals, such as lignin. Preservatives containing lignin-rich compounds help restore and maintain the integrity of wood, preventing decay and rot.
A variety of wood preservatives are available, depending on the location of application and desired end-use. Some commercially available wood preservatives include copper azole, alkaline copper quaternary (ACQ), and chromated copper urea. These products have lower toxicity profiles than older chemical preservatives.
The most effective way to treat wood is by brushing or spraying a preservative. However, unless the wood is soaked to the point of puddling, penetration may be limited and a thin layer of preservative can be lost as it evaporates or runs off. Traditional brush or spray applications of small quantities of coal-tar creosote are still practiced today to add 1 to 3 years of life to telegraph poles, railroad ties, and utility poles.
Some wood preservatives require pressure to penetrate wood fibers and become absorbed by the wood cells. Pressure treatments are commonly used to treat lumber and other wood products that are in ground contact, above ground, or exposed to freshwater or marine environments. These wood products being pressure treated include landscape timbers, fence posts, building and utility poles, decking, and marine pilings.
In addition to the above-mentioned water-borne wood preservatives, several fumigants are also used to treat timber-treated lumber and other wood materials. Fumigants such as methyl isothiocyanate (misc), ethyl isothiocyanate, and methyl bromide control existing internal decay, fungi, and insect infestations in treated wood. They also help prevent future problems by creating a toxic environment in unfinished wood that is hostile to wood-destroying organisms.
