Most homeowners have some sort of wood deck attached to the outside of their house and may also have outdoor wood furniture. Because most existing decks have a useful life of 15-20 years, rebuilding decks and replacing outdoor furniture is common. Are there materials that are superior to pressure-treated wood?

Wood is wonderful stuff; strong and relatively light, easy to work with and pleasant to look at when it’s in good condition. Most decks in the US are made with pressure treated wood, which is pine with its exterior treated with chemicals to discourage invasion by insects or fungi that cause decay.

But pressure-treated wood is only one of your choices, and a poor one at that. Alternatives include US softwoods that are naturally resistant to decay, imported hardwoods that are resistant to decay, plastic materials, or naturally decay-resistant US hardwoods.

The fact is that nature figured out how to resist decay without environmental risks millions of years ago. Almost every continent has rot-resistant wood species that will do the job. These woods have always been available to us; we just lost the knowledge for a while and are recovering it now as we realize both the importance and fragility of our environment.

First, a little background:

It is the outside layers of a tree’s trunk that do the growing. These layers form the sapwood that is the living part of the tree trunk, and carry water and nutrients up from the soil around the tree to its leaves, where the tree uses sunlight to generate its energy and food. We call this liquid mix of water and nutrients sap. This growth layer expands outward as the tree grows, depositing new sapwood. As further new layers grow on the outside of the tree each year, the inner layers age, die, and become heartwood. This is the core of the tree. As these inner rings convert to heartwood, chemical conversions and mineral deposits give them greater strength and resistance to insects and decay. Heartwood is the supporting backbone of the tree; it is typically darker in color than the sapwood surrounding it.

Many tree species have little decay resistance, while a few have excellent resistance. In the US, there are several trees with good to high decay resistance, and a couple that are excellent. You are probably not aware of these two US hardwoods; both of which have excellent qualities as outdoor woods. Sharpbuzzworks handles both:

White oak has high resistance to decay and insects, while black locust has superior resistance. Both are very hard and dense, and will far outlast pressure treated wood, and they do it naturally. Black locust is native to the appalachian mountain and south central regions of the US, and has been transplanted throughout the US and to several other continents. White oak is native to most of the eastern US. [Photos of both woods]

As a matter of fact, a few people are using them. As noted above, this is lost knowledge. Many people used to know how to use these woods, but most cultures forgot about it in the last hundred or so years. Amish farmers have long used black locust for fence posts. They have a saying about how long black locust lasts: “Same as stone, plus 10 years.” It’s not quite that long, but you get the idea.

Black locust is suddenly popular with vineyards as posts to hold up grape vines. Set directly into the soil, black locust will last several decades; 50-70 years or more. I have personally pulled black locust logs out of wet soil where they sat for upwards of 30 years. The outer 1/8 inch of the wood had degraded; the rest of the log was in excellent shape; I made a cutting board of of some of this wood. [Photo]

Both black locust and white oak were commonly used as the wooden spikes that held post-and-beam structures together, taking the place of nails hundreds of years before nails were invented, going far back into history. Some post-and-beam structures still standing are many hundreds of years old, so those spikes did their job well.

Black locust was used by early settlers in the US under sill beams, the bottom support for early houses that sat on stone foundations and had to withstand exposure to water. Some builders still use it for this purpose. Early settlers often cultivated black locust for this, and it was taken back to Europe and grown there as early as the mid-1600s, and is still grown there today.

Both black locust and white oak have been used in one of the harshest environments known for wood applications: shipbuilding. The USS Constitution, nicknamed Old Ironsides after British cannonballs bounced off its hull during the War of 1812, had hull planks made of white oak, and the wood was fastened together with “treenails” of black locust.

So the use of these woods is not new; it’s an old idea that is coming back because it is better and less harmful than alternatives like pressure-treated wood, aesthetically more pleasing than using plastics, and more “green,” and less environmentally harmful than importing woods from the tropics. What’s more, both of these woods have visual appeal. White oak when quarter-sawn exhibits stunning ray-fleck patterns, and black locust often has a stunning rich gold color and shimmering appearance that is just as appealing as any wood you can get by destroying a rain forest.

Most lumberyards and big stores do not supply either of these woods. And please note:

Contact Sharpbuzzworks for help. If you are reasonably close, we can help you directly. If you are farther away or current supplies are low, we’ll direct you to another supplier. Sharpbuzzworks works in cooperation with other environmentally responsible wood producers to help ensure your needs are met.