Keeping wood in good condition can be challenging, but what if your wood could help you ward off rot? Well, if you choose the right wood, it can! Some types of lumber naturally fight against decay, making them much more long-lasting and desirable than other types of wood.
Here are the 10 of the best woods that do not rot:
- Bald Cypress
- Black Walnut
- White Oak
- Black Locust
These woods are especially effective at fighting against the fungi, microbes, and insects that cause wood to rot. Let’s talk more about what makes certain kinds of wood rot-resistant and go into all the details. I’ll tell you everything you need to know to figure out which type of wood is right for you.
What Makes Wood Rot-Resistant
Not all wood is created equal, and if you want to find the most durable, low-maintenance lumber for your building project, you’ve probably wondered what makes some woods more resistant to decay than others.
Trees with large quantities of heartwood, natural oils, and extractives are significantly more rot-resistant than other woods.
So, what does that mean for you, and how do you know what woods will stand up best to the elements? Let’s talk about it below.
Rot-resistant woods are only effective at fighting against fungus if you use the heartwood. Heartwood is the wood from the core of the tree. The wood next to the bark, called sapwood, is not resistant to rotting, and it is just as susceptible to decay as any other wood.
With deforestation on the rise, it has gotten even harder to find heartwood these days. Heartwood is most abundant in old-growth trees, which have thick, dense trunks. Most of the wood of today is from new-growth trees, which are narrow and not rot-resistant.
Since there isn’t much heartwood available these days, it might cost you a lot of money to use heartwoods in your building projects. Still, their durability assures that they will last for many years if treated well, so it is well worth the investment.
Have you ever treated your wood furniture with olive oil, mineral oil, or linseed oil to keep it in tip-top shape? Some woods contain their own oils, waxes, and resins, which work just like those superficial polishings, but they keep the inside of your wood in good condition.
Natural oils keep humidity and water from getting inside the pores and fibers of your wood. Since most wood-eating fungi only grow on damp lumber, choosing oily trees for your building project will ward off rot.
These oils can dissipate over time, but if you keep your wood oiled or varnished on the surface, its natural oils will stay locked inside the wood. Keeping your wood sealed will keep it from getting too wet– and from developing wood-eating fungi!
Rot-resistant woods still rot over time, but they are less likely to host the fungi and insects that cause wood to decay. That’s because they contain certain antimicrobial chemicals called extractives.
Extractives are organic compounds that help trees turn their freshly-grown sapwood into durable heartwood. Most of the time, they contain components like triglycerides, polyphenols, resin, and sterol. These chemical compounds naturally protect the wood from humidity, microbes, and fungi, making them much more resistant to rot than other types of wood.
According to a 2013 study, when the extractives are removed from rot-resistant woods, they decompose just as quickly as fast-rotting wood. So, the more extractives a tree has, the better it will be at fighting off fungus, termites, and other decomposers.
Now, let’s talk about what trees have heartwood and high enough levels of extractives and oils to be rot resistant. We’ll go over the best woods that do not rot and the unique benefits of each type.
Cedar is one of the best woods all-around. In addition to its durability and rot-resistance, it smells great and repels moths, termites, and other insects. Cedar is so good at resisting fungi and other microbes that many people use cedar oil as a topical antibiotic for acne and other skin conditions.
Because cedar is a very oily tree, it has some natural waterproofing properties. It also doesn’t have much resin in it, meaning that it holds paint, glue, and varnish better than many other kinds of wood.
Cedar comes in many varieties, but the most popular for building projects are:
- Northern White Cedar
- Western Red Cedar
- Yellow Cedar
- Spanish Cedar
Cedar is a relatively soft wood, but it is still very durable. It is flexible, making it resistant to cracking and warping. Because of all of these benefits, it lasts an extremely long time.
Although cedar has been known to resist decay for upwards of 40 years untreated, it does lose some of its beautiful color and scent over time if you do not treat it with a UV-resistant varnish once or twice a year.
Redwood is one of the most popular rot-resistant woods for building houses. Redwood trees are some of the tallest trees on the planet, and they grow in the Pacific Northwest and New Zealand. Because of their length and durability, redwood trees make excellent furniture, decking, trim, and structural beams.
Moreover, redwood is highly durable because most of the trunk is made of heartwood. That means redwood is also rot-resistant since it has high levels of extractives. Redwood is much more sustainable than other woods since the others take much more time to develop strong heartwood cores.
Although American redwood is a protected species, it grows quickly in New Zealand, where most commercial planks and beams are harvested.
Redwood is a dense softwood, so it is straightforward to work with, especially considering how well it stands up to pressure. It doesn’t warp much either, so it is a fantastic structural building material. The color of the heartwood is usually very red, and it has white sapwood. So, if you are using redwood, avoid cuts with white and go for pure red planks.
Mesquite is one of the hardest woods you can find. It is fast-growing, so it is likely easier to source than most other rot-resistant woods.
It is also a beautiful deep red color with stunning burls and knots, making for a very dynamic-looking wood.
However, mesquite trees are short and knotty, so you might have trouble finding large planks or beams made from this wood. Because of their stout and irregular stature, mesquite trees are usually best used as smaller items like tables, small furniture, cabinets, floorboards, and trim.
Because of its hardness and size, it can be challenging to work with mesquite, but it is well worth the effort.
Mahogany is one of the most well-known woods because it is renowned for its rot resistance. It’s usually considered to be a premier wood because it lasts so long. It is exceptionally durable and has a beautiful red color that makes it popular and usually rather expensive.
Additionally, it is dense yet soft and flexible enough to work with efficiently. No matter how wet it gets or how quickly the temperature changes, it won’t shrink or warp either. So, you won’t have to worry about cracking with mahogany.
Mahogany is a naturally oily wood, making it relatively water-resistant. Because of its weatherproof properties, mahogany is a popular option for outdoor applications like decks, outdoor furniture, and siding.
Yew is both durable and flexible, making it one of the most durable and warp-resistant woods worldwide. It does not have as many extractives as some of the other trees. However, it contains a chemical that makes it toxic to insects and fungi, so it is still highly rot-resistant.
Also, yew has very straight grains, making it easy to work with and beautiful to look at. The heartwood is usually a deep orange-brown color with a natural glow that comes from its oily texture.
In addition, yew also holds onto wood glue and paint very well, making it an excellent choice for wood siding and cabinetry.
So, if you want a flexible yet rot-resistant wood, yew is the way to go.
6. Bald Cypress
When it comes to bald cypress trees, only the heartwood is considered to be durable and rot-resistant. The heartwood is a very light, yellowish color, and the sapwood is cream or white-colored. So, make sure that you pick the darkest shade available if you are interested in purchasing rot-resistant wood.
Bald cypress trees grow next to water sources in nature, so they have oily, waterproof heartwood with a beautiful shiny luster. It is an exceedingly hard wood, too, and it has been known to take a lot of effort and a very sharp blade to cut.
Because of its natural water resistance, bald cypress is an excellent choice for building in wet, marshy, or humid places. This wood is best for decks, outdoor structures, and siding. It is commonly used for docks and boatbuilding, too.
7. Black Walnut
Black Walnut is a durable wood with plenty of extractives, making it a rot-resistant wood.
However, black walnut is much more vulnerable to insect infestation than the other woods on this list since it has large pores that insects like to hide or bore in. Still, if you apply a varnish to your black walnut, insects won’t be able to get into the wood.
Black walnut is dark brown, and it has a very light, almost white sapwood. Always try to get the heartwood if you choose black walnut.
Some people stain the sapwood to make it look more like the heartwood, so it would be best to inspect the ends and scratch the wood to check for varnish. Be sure to examine all of the wood for white streaks before buying it to make sure you get the durable, flexible heartwood.
Black walnut holds glue and paint very well, so it is an excellent wood for furniture, shelving, cabinets, trim, and veneer. It is also a popular wood for musical instruments, bowls, and carving.
8. White Oak
White oak is so durable and rot-resistant that it is a favorite wood for boat building. It is oily and naturally waterproof, so you can be sure that white oak will withstand high weather stress gracefully, no matter what you are building.
It can be challenging to tell the difference between the sapwood and heartwood with white oak. Both are very light and olive-yellow, but the sapwood is slightly lighter.
Although white oak is exceptionally durable, it is also very flexible and susceptible to warping. So you will need to keep it well-varnished if you are using it in an outdoor application.
White oak is also much less expensive than the other woods on this list, so if you are looking for the most economical approach, this wood is the way to go. It is perfect for almost any job, from flooring and cabinets to barrel building and veneer.
One of the more exotic rot-resistant woods is teak. It is native to Southeastern Asia, and it has been one of the best boatbuilding woods for many centuries.
Teak is highly prized for its longevity and waterproofness. It is a waxy, oily wood that has a fragrant, pleasant odor. It has exceptionally high levels of extractives, too, so it is one of the most rot-resistant woods in the entire world.
While teak might seem like the complete package, and in many ways, it is, it comes at a high price. Harvesting teak wood is a complicated process, and it can take many years for the tree to get big enough to be worth harvesting.
Still, teak’s incomparable durability and beauty make it worth the high cost for many people. It has a lustrous, golden-brown to dark brown color that is hardly ever covered with stain. Teak is also unbelievably water-resistant, so using glues and paint on it might be a challenge.
Generally, it is most commonly used for carvings, furniture, boats, cabinets, and pavilions.
10. Black Locust
Black locust wood, commonly used to make fence posts, railroad ties, ships, and mining beams, is one of the strongest woods that you can find. It comes in many colors, from olive to dark brown, and it darkens with age.
If you are looking for a good wood for outdoor structures that must take a lot of weight, locust is the way to go. Locust is made up of mostly heartwood, so it is easy to get the most rot-resistant cuts when you purchase it. In addition, it stands up exceedingly well to weather and decay.
Because of its rigidity, black locust wood can be challenging to cut and carve. Often, it is so strong that it dulls axes and saw blades.
Black locust is also one of the more moderately priced woods on this list, so you might want to consider choosing this wood if you are looking for something affordable.
Woods That Rot the Quickest
If you want to know what woods you should avoid for outdoor building projects, I have you covered. These are some of the most common building woods that rot the fastest:
Generally, soft, resinous woods are the first to decay. So, you might want to avoid soft, splintery woods that have sweet resins if you want to build something that stands up against rot.
You may also like: How to Repair a Rotted Window Frame
Pro Tips for Avoiding Wood Rot on Rot-Resistant Woods
Whether you are building a house, a bench, or carving decor, choosing rot-resistant woods will increase the longevity and durability of your project. However, even though they do stand up well to humidity, sunlight, and other harsh conditions, taking care of them will keep them healthy and beautiful for many more years than if you left them untreated.
To keep your wood in the best condition possible:
- Varnish wood before installation. If you treat your wood with a quality sealer or varnish before installing it, you can protect every side of the wood from decay and insects.
- Coat your wood with a UV-resistant sealer or varnish every year. Even rot-resistant wood will look washed out and dry after a year of exposure to sunlight and humidity. To keep up with maintenance, apply a coat of UV-resistant varnish every year to keep the wood oily, protected from the sun, and sealed off from decomposers. Be sure to coat the ends of the boards, where they are most vulnerable to insects and fungi.
- Seal the joints. In places where the wood is jointed, seal the gaps with a waterproof sealant like silicone caulk. Doing so will prevent moisture and insects from getting on the unfinished ends of the wood.
- Keep objects off of the wood. Although it is impractical to keep the wood clear of all objects, try to keep debris like leaves, boxes, pillows, and other moisture-trapping things off the wood. It would also help if you moved any furniture sitting on wood surfaces about an inch or two every few months to dry out the wood.