Photo Credit: giovzaid85
Especially in warmer climates, termites are a constant threat even to the most skillfully crafted wood structures. Termite damage isn’t inevitable, though. Choosing termite resistant wood goes a long way toward preventing these bugs from making a meal of your property.
Natural Termite Resistance
Termites live on the cellulose found in wood or certain other plant materials, such as cotton. While they can eat any type of wood, there are some species they prefer to avoid as much as possible. Broadly speaking, termites dislike heartwood. This is the dry, non-living inner part of the tree truck. Heartwood contains less cellulose than the outer sapwood, making it less nutritious for termites.
If you’re choosing wood for its termite resistance, look for heartwood grade lumber. This lumber typically has the word “heart” in the grade name, such as “Clear Heart” or “Heart B.” As an added benefit, heartwood is also more resistant to rot than other grades.
Some tree species have a natural resistant to termites. They’re not impervious to these bugs, but they’re highly unattractive to them and unlikely to be eaten. Cedar is tops among these. This includes southern red cedar, western red cedar, and Alaska (yellow) cedar, among others. Availability varies by region, but western red cedar lumber can be found in most areas.
Redwood lumber, popular for its rich red-brown color, is also distasteful to termites. It’s most widely available where it grows on the west coast.
Cypress, in particular Arizona cypress, bald cypress, and tidewater (red) cypress is another good choice for discouraging termites. Its durability, along with the visual appeal of its light color and straight grain make it ideal for exteriors and interior trim.
White oak and chestnut oak resist termites well. White oak is a common choice for flooring, thanks in part to its wide availability. Chestnut oak lumber is less common, but when available, it’s often sold as “mixed white oak.”
Other naturally termite-resistant wood species include:
- Black cherry
- Black walnut
- Chestnut
- Honey mesquite
Depending on what you’re planning to build, however, some of these woods may not be practical choices. Due to their cost, hardwoods such as cherry, walnut, and chestnut are typically reserved for use in fine furniture and cabinetry. Honey mesquite is relatively rare and may be hard to find in large quantities
Wood Products Designed for Durability
If none of the wood species with the greatest natural resistance to termites are right for your needs, there are some alternatives worth considering. These products typically do an even better job of holding off termites than natural woods.
One of these is pressure treated wood from any tree species. Pressure treated wood has undergone a process that impregnates the wood’s pores with chemical preservatives, making it nearly impervious to rot and insect infestations. For health reasons, this wood should not be used where food is grown or prepared or for children’s play equipment.
Composite lumber, made by combining waste wood fiber and plastic, is completely impervious to termites. Offering the beauty of natural wood at a lower cost, composite lumber is popular for use in decks, furniture, and siding.
Termite Favorites: Wood Species to Avoid
Just as some wood species strongly repel termites, others tend to attract them. Even if you decide against the most resistant species, you can still avoid turning your building project into a termite smorgasbord of their favorite foods.
Of the wood species most commonly used for building–Douglas fir, spruce, and hemlock–only Douglas fir is somewhat resistant to termite. It is best to avoid spruce and hemlock if termites are abundant in your area. Pine is another popular construction wood, but it’s also the wood termites seem to prefer above all.
Don’t make the mistake of assuming related wood species are equal in their ability to discourage termites. While these bugs steer clear of white oak, they’re happy to nibble on black oak and red oak. Honey mesquite is relatively resistant to termites, but black mesquite is not.
Also get familiar with the alternative names used for the species you’re interested in. Cedar and cypress are closely related and the names are sometimes used interchangeably. Yellow cedar and yellow cypress are, in fact, the same species. If you’re uncertain about the products available at your local lumber yard, ask before you buy to make sure the species you’re getting has a good chance of standing up to termites.
References
https://edis.ifas.ufl.edu/fr075
