The best way to treat untreated wood for outdoor use is by applying a wood sealer, varnish, or finishing oil to the surface of the wood.
Untreated wood is the most susceptible to rot, fungi, and general weathering. It's extremely important that you use a wood preservative first. You can either use a wax enriched preservative for an all-round coating or alternatively use a wax-free preserver if you want to then use a stain or a paint on top.
There are several types of finishes that work well for outdoor wood, including polyurethane, lacquer, varnish, and epoxy. Choose a finish that is appropriate for your specific project and follow the manufacturer's instructions for application.
Untreated wood can last anywhere from a few months to several years, depending on different factors such as the type of wood, the climate, and the level of exposure to the elements. For example, cedar and redwood are naturally resistant to decay and can last up to 20 years or more.
But building code dictates where you can use treated wood in applications — usually where there is risk of excessive moisture. Generally speaking, any wood used in outdoor projects should be pressure-treated. Wood details in your interior design (like cabinetry or furniture) do not need the same level of treatment.
The difference between the two is that pressure treated lumber will resist the elements better than untreated due to chemical preservatives added, and so will maintain its integrity in conditions that would cause normal wood to rot.
Wood can Start to Rot in 1-6 months If:
Wood is untreated. The wooded area is sitting in water. Water and/or air space is hot & humid.
Even loose lumber not treated in any way will be fine; provided it has an opportunity to dry out before covering with drywall. To minimize and eliminate any potential damage to the material, it is important to remove any standing water on the sub floor. This will help the water to dissipate quicker.
Storing dry lumber outdoors should be avoided at all costs. The outside elements include water and drastic changes in temperature.
Wet rot is decay that occurs in untreated wood that is routinely exposed to water or high moisture levels. The moist wood attracts a fungus that feeds on it and grows. Although most decks are built with pressure-treated lumber, they can still get wet rot.
Boric acid (borate) is one of the most effective fungicides for use in treating wood rot. It can be applied to wood during construction to prevent future rot, or as a treatment to stop an active decay fungus from growing.
Indoor wood furnishings can easily be upgraded into beautiful outdoor features, but first be sure to add weatherproofing sealants so the furniture can withstand sunshine, moisture and extreme temperature fluctuations.
A combination of mineral spirits and baking soda is powerful enough to remove oil stains, grease, and grime from the surface of unfinished wood. Because of the nature of the materials, ensure you wear protective gloves and open all windows for proper ventilation.
Whenever possible, wood should be stored indoors in a cool dry location. But if you must keep it outside, it's best to have it covered at all times.
Paint Or Seal Unfinished Furniture
Bare wood, when left unfinished, keeps your furniture with a natural wood look but the risk is exposing it to harsh elements, even if it's indoors, such as light, dust, moisture and water damage, making it more susceptible to stains, warping and cracking.
Most of the furniture won't be ruined if some water gets on it for a few minutes. Although, if your furniture gets damp and stays wet for a long time, it can be harmful and can cause damage to the wood. To prevent damage, it is in your best interest to prevent moisture from coming into contact with the furniture.
Lab experiments have recorded that dry rot spores can germinate approximately seven to ten days after the wood has become damp enough. Older spores can take longer to germinate. As mentioned earlier, though, it can take a long while for signs of dry rot to appear after germination.
Iron oxide stains in wood are usually dark spots caused by prolonged exposure to water and / or metal. The iron oxide reacts with the tannins in the wood and stains it black. Wood can intentionally be stained black in the same way, and that's called Ebonizing.
One of the main differences between wet rot and dry rot is that wet rot needs a higher moisture content to grow. Wet rot fungus likes to grow on timber with a high moisture content of around 50% and above while for dry rot to grow it will germinate at a lower timber moisture content of around 20% to 30%.
When it comes to comparing treated wood vs. cedar, pressure-treated wood is the sturdier and more weather-proof of the two. It's highly resistant to insect attack and rot, and special versions rated for “ground contact” can be buried in soil and will continue to shrug off decay for decades.
Do not use treated wood for cutting boards or countertops. Only treated wood that is visibly clean and free of surface residue should be used for patios, decks and walkways.