The three most widely available and suitable exterior lumber choices, not treated with chemical preservatives, include Western red cedar, redwood, and cypress. Your geographic location will determine the availability and cost of these materials.
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.
Choose Rot Resistant Wood for Your Project
Well-known domestic examples include cedar, redwood, old-growth cypress, mulberry, yew, osage orange, and black locust. Tropical wood examples include ipe, lignumvitae, purpleheart, and old-growth teak.
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.
Untreated Wood means wood (including lighter pine, tree trunks, limbs and stumps, shrubs, and lumber) which is free of paint, glue, filler, pentachlorophenol, creosote, tar, asphalt, chromated copper arsenate (CCA), and other wood preservatives or treatments.
Cedar wood projects typically last more than 20 years without splitting, rotting, or warping. White oak and teak are also long lasting woods that are resistant to decay, twisting, cracking, or warping.
Wood that is naturally durable for decay and termites, as defined in IBC Chapter 2, includes the heartwood of redwood, Alaska yellow cedar, eastern red cedar, and western red cedar.
Characteristics of Redwood and Cedar
When you're looking for the best wood for outdoor use, both of these types of wood are naturally resistant to rot and decay, along with being termite and insect-resistant. Redwood and cedar are also known to: Resist warping and twisting.
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.
Pinewood is an outstanding building material. It's a versatile product. However, it's also prone to moisture and decay, just like other wooden materials. Hence, to protect it from decay, it has to undergo wood treatment.
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.
Naturally resistant woods that are commercially available include black locust (Robinia pseudoacacia), teak (Tectona grandis), ipe (Tabebuia spp.), California redwood (Sequoia sempervirens) and bald cypress (Taxodium distichum). These have the highest resistance to rot over time.
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Burns well but has a tendency to spark. Birch burns easily and can be burnt unseasoned. It also burns very quickly so is often best mixed with a slower burning wood such as Oak or Elm.
Redwood works well for outdoor projects. It naturally resists rot and is more attractive than pressure-treated wood. Cedar resists rot, especially when treated regularly with a preservative. It is a popular and highly attractive choice for outdoor projects.
If you're looking for a durable, long-lasting material that's resistant to rot and decay, cedar is a good choice. Cedar is more expensive than pressure-treated wood. Cedar has a more natural look that many people find appealing.
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.
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.
Wood can Start to Rot in 1-3 Years If:
Wood is untreated. The wooded area is in a hot climate. The wooded area is not painted with the proper paint. Wood collects water on a frequent basis (from rainfall, leak in plumbing pipes, or sprinklers)
Since it's widely available, fir can be useful for those running a slightly tighter budget. It's one of the cheapest woods for outdoor use. If you're a woodworker or DIY garden furniture maker, this species also works and machines well, in addition to holding finishes easily — whether a clear varnish, stain or paint.
Pine does not naturally resist decay, and it is pressure treated to make it more durable outdoors. So cedar gains a bit here with its natural character contributing to its durability. Pine is still a good choice for outdoor furniture, it just doesn't naturally resist the elements as strongly as cedar does.
Cedar is also softwood but it's tougher and more resistant than pine, able to resist the outdoor elements with no further treatment. This is why it's a great choice for outdoor tables and yard furniture. Cedar can also be used indoors for chests, wardrobes, and musical instruments.
Pine. Pine wood is probably the cheapest wood that you can get on a consumer level, but it is also one of the best wood options when high strength and low cost are needed. Pine wood is sourced from the dozens of different pine species that grow natively around the world.
Heirloom-quality handmade wood furniture should last more than a lifetime. In fact, it can last for decades if properly maintained. This type of wood furniture is more likely to reach the “antique” milestone, meaning it can last 100 years or more.