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.
Generally, you can use non-pressure-treated wood outside for about 2-5 years if it is not maintained or protected from high humidity, heavy rain, or prolonged exposure to sunlight. Also, untreated wood outdoors will not last as long as pressure-treated wood.
Some say that untreated 2×4's can last up to two years before showing signs of rot and others say it can last even longer. When deciding if you should you use an untreated 2×4 it depends greatly on the application, how much weather and sun it's exposed to and if it's making ground contact.
Untreated Wood
Left in their natural, unfinished state, most woods deteriorate quickly when exposed to outdoor environments. However, there are several species that have naturally occurring chemicals that help them shrug off harsh weather and insects.
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.
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.
Seasoned logs are traditionally stacked neatly, close to (not touching) a wall or fence, it is important to be quite precise as tight stacking will ensure that only the top layer will get damp if it rains.
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.
Naturally Resistant
To deter the pests, homeowners can obtain heartwood-grade lumber for construction projects. Termites also tend to avoid specific species of trees such as redwoods, yellow cedar, Laotian teak, and cypress. However, these types of wood are not as long-lasting as treated lumber.
For example, Teak doesn't need any treatment which prolongs its lifespan because it is naturally durable and doesn't have much movement whereas kiln dried Oak does need treating to prevent it from: Losing moisture and shrinking in the summer.
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.
Fully clean the wood with biocidal cleaner and apply an undercoat wood preservative to protect against woodworm and rot. If you'd like to give your outdoor wood a new look, stain the wood to a vivid colour or subtle tint. Finishes seal the wood from moisture, rain and (with some finishes) UV radiation.
Normal rainwater will not harm the wood that is used to build homes. Many homeowners fear that wood will immediately rot if allowed to get wet. That's simply not the case.
1. Apply a coat of polyurethane, varnish, or lacquer to protect the wood from penetrating humidity and moisture that can seep into your deck and other outdoor wood furnishings. 2. Finish and waterproof wood with a professional-grade wood stain and sealer combo and repaint when necessary.
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.
Pressure-treated wood may be protected for a while, but if it stays damp enough for long enough and starts to rot, termites can feed on it.
The best water resistant wood types & species. Iroko, Oak, Western Red Cedar, Cherry, Maple and heat-treated woods are just a few examples of timber that boast excellent dimensional stability and high resistance to shrinking and warping in the face of moisture.
Ground-contact lumber is, as the name suggests, suitable for contact with the ground. It's commonly used for pressure-treated posts and some framing. Containing a greater amount of chemical treatment, these wood products can last much longer than aboveground lumber, and up to 40 years, in some cases.
The speed and spread of rot can vary widely. However, all cases of rot require the proper conditions to “activate,” so to speak. These conditions include oxygen, proper temperature (often between 65 and 90 degrees Fahrenheit), moisture, and “food” (wood, in this case).
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!
Unless you want spiders, mice, ants, termites, or a number of other pests crawling around your home, keep the wood outside. Besides, it's less likely to age well in the house where there's less airflow to dry it.
The best place to season your firewood is outside in the sunlight. Firewood that is placed indoors will not season properly and there is always the risk of termites entering your home. If you live in a rainy area, open-air storage like a barn or shed is another option, but ensure that the wood gets quality airflow.
To identify well-seasoned wood, check the ends of the logs. If they are dark in colour and cracked, they are dry. Dry seasoned wood is lighter in weight than wet wood and makes a hollow sound when hitting two pieces together. If there is any green colour visible or bark is hard to peel, the log is not yet dry.