Untreated lumber, such as pine, is the least durable . It will warp and begin to rot within three to five years. Cedar and redwood are naturally resistant to both rot and insect infestations, which is why they're often used for decks and fences.
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.
As a whole, untreated wood can be used outside. Proactive steps should be taken to make untreated wood a viable option for long lasting projects when used outdoors. Steps such as sealing, painting or using other bonding agents to increase the life of untreated wood.
But don't worry, framing material is made to withstand exposure to moisture. In fact, the glues used to manufacture OSB (Oriented Strand Board) are water-resistant. Even loose lumber not treated in any way will be fine; provided it has an opportunity to dry out before covering with drywall.
Use an outdoor-rated finish like polyurethane, epoxy, lacquer, or varnish. Make a natural oil finish with one part tung or linseed oil, one part mineral spirits, and one part polyurethane. Use a stain sealant combo that gives your wood some color and a durable finish all in one.
Redwood and Cedar. While pine is the best exterior softwood for the money, Redwood and Cedar are better exterior softwoods for stability. Redwood and Cedar are pinkish, with heart redwood being a darker pink than Western Red Cedar.
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.
Wood rot can and will start when the moisture content of the wood reaches 20 percent. But wood rot is a slow process where the fungi start to grow and feed on the cellulose in the wood. The wood needs to remain damp and wet all the time for wood rot to advance.
Place a cover tarp loosely over the lumber stack so that air can circulate freely – don't wrap the stack tightly in plastic, since this will trap moisture from the wood under the tarp.
Wet lumber will naturally dry out if given enough time. If the outdoor temperatures are above 60 degrees F, it usually takes about 4 weeks for moisture content to decrease about 4%. It might take 6-12 weeks for a 4% drop if its cold and rainy. And if it's below freezing, it might take many months.
Depending on outside conditions and lumber species and size, air-drying to a desired MC can take from several months to almost a year. Wood stored outdoors and under cover will dry to an approximate moisture content of 12 to 14 percent in western Oregon and 8 to 10 percent in eastern Oregon.
Weather: Water, wind, and sun can all cause extreme damage to your outdoor wood structures. Anything from discoloration to deterioration can be the result of weather damage. Properly clean and apply stain to your lumber to protect it from these harsh elements.
But what happens when wood is exposed to the sun's rays and moisture from the rain? In simple terms, the surface of the wood starts to break down and decay, and the wood begins to split, rot, warp, lose its rich colouring and literally fade to grey.
Dry rot will likely require a professional. Unlike wet rot which can be eliminated by finding the source of moisture, dry rot will continue growing even when you've dried out the area. Once it gets going, dry rot can feed on the moisture in the timber. So as long as you have timber, it has food!
Framing can generally be exposed to the weather for around three months with no issues, but the number drops if your area has extreme weather. The amount of framing damage sustained depends on exposure time, wood quality, whether the wood is treated or untreated, moisture, and temperature levels.
Unload lumber in a dry place – not in wet or muddy areas. Elevate lumber on stringers to prevent absorption of ground moisture and to allow air circulation. Do not store lumber in direct contact with the ground. Cover lumber stored in an open area with a material that will give protection from the elements.
Seasoned wood: Any kiln-dried lumber or seasoned wood should be kept indoors whenever possible. Ideally, keep this type of wood in your workshop. If not, storing lumber in a garage, shed, or storage unit will work. Do your best to keep moisture out of these areas so the moisture content of the wood does not rise.
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.
Normal rainwater will not harm the wood that is used to build homes.
Wet rot needs a lot of moisture in order to grow, while dry rot can continue to spread regardless of whether the infected area is wet. Fortunately, this means that wet rot often confines itself to those select, damp areas.
With concrete holding the moisture against the wood, wood has no chance and will eventually lose the battle. Now you don't have to lose all hope because it's for certain that the concrete around the post will crack, therefore making it easy to pull out when it starts to rot.
One popular remedy for wood rot is vinegar because vinegar's acidity has the ability to act as a fungicide that kills off fungal spores.
Which Wood Lasts the Longest? Teak wood easily lasts the longest when used for outdoor furniture or decking. When properly maintained, it can last for the entirety of your life and years after.
While redwood or teak certainly qualify, five more common lumber species that also stand up well to sunlight, moisture and wood-boring insects are Western red cedar, Spanish cedar, cypress, white oak and mahogany. Red cedar tends to be knotty, but it's affordable and widely available.