The three most widely available and suitable exterior lumber choices, not treated with chemical preservatives, include Western red cedar, redwood, and cypress.
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.
Ipe Wood. Ipe wood can last up to 50 years outside without needing replacement. This wood has become more popular within the last 10 to 15 years and is known best for its tight grain, reddish-brown color, strength, and durability. This exotic hardwood can last you a lifetime if cared for and maintained properly.
Using untreated wood for outdoor decks is not advisable because it is susceptible to rot and decay when exposed to moisture and other elements. Over time, untreated wood can become weak and unstable, posing a safety hazard for outdoor deck use or any other outdoor projects.
Varnish is great option to treat untreated wood for outdoor use because it's relatively cheap and provides superior protection for your wood. It can also last longer than some other sealants, which is something we all want.
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.
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.
Cedar wood may last over 20 years when used in outdoor structures, such as decks, pergolas, gazebos, or furniture. It can last between 15 and 20 years when used for constructing a fence or support posts.
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.
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.
Teak. Teak is the most highly recommended material for wooden outdoor furniture among designers, not only due to its resilience in any season but also because of its style and soft, grained finish. This miraculous material produces its own oils, making it unique in comparison to other types of natural woods.
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.
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.
Did you know that untreated cedar wood changes color over time? Cedar wood has unique qualities and properties that make it an excellent fencing material choice, but a cedar fence can quickly change color from that beautiful red color it was when it was first installed to a silvery gray.
Additionally, porous cedarwood can collect moisture from the air, promoting mold and mildew growth. Use a wood sealant to help shield your cedarwood from the elements to help avoid weather-related damage.
If you are looking for a natural, sustainable, and durable option, cedar is the better choice. However, if cost is a major concern, treated lumber may be a more cost-effective option.
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.
Can Water Seal be used on wood? Applying Water Seal will not damage wood, but the level of waterproofing protection will vary depending on the type of wood being treated. For best results, we would recommend a dedicated preserver to protect exterior timber from rot.
Paint protects the wood and also seals the tiny cracks and gaps that you might not even know exist in your building's exterior. These small blemishes start to get bigger if they're left without any treatment. Sooner or later, you'll have to deal with a much larger and more expensive problem.
All unfinished wood or bare wood surfaces should always be primed prior to painting. This goes for both interior and exterior paint projects. The reason you cannot skip bare wood priming is that wood is porous and has a grainy surface. Because primer contains high solids, it helps fill grains in the new wood.
The longer lifespan of pressure-treated lumber is one of the most significant advantages. Although its lifespan is short compared to composite materials, it will last much longer than untreated wood. Depending on its use, pressure-treated lumber can last up to 40 years when properly cared for.
While treated wood has distinct advantages, you might decide that they aren't worth the added health risk. Yet, if you need something to last a long time and you know people won't come into much contact with it, treated lumber might be the better choice.
To make wood waterproof naturally, use either polymerized linseed oil or tung oil, which are the two best natural wood waterproofing products. Refined hemp oil and walnut oil can also be used, but you will have to apply a repeat coat more quickly.
Sealers. Sealers are usually transparent paints applied over the wood furnishings to make them waterproof. It helps provide a protective layer over the wood and showcases its natural beauty. The sealer protects the wood and prevents moisture from seeping in.