Know your wood
Whether you’re building a deck or a lavish stable, decisions about building materials are critical to the durability and appearance of the project. As a general rule, the long-term performance of wood, or composites, weighs heavily on material quality and decay resistance, either natural or that imposed by chemical treatment. A quick review of the following basic materials, both the advantages and downfalls, may aid in the decision-making process for your next project.
Prevalent in the Pacific Northwest, cedar trees have developed self-protective qualities that allow the trees to fend off insects, rot and temperature related stresses. That makes cedar very useful in structure building where humidity, temperature, and cracking are a common problem. Cedar is not typically used as a structural component in construction because it is much weaker than its counterparts; redwood, cypress, or pressure treated lumber. Cedar is best used as the decorative, exposed portions of a project. Cedar is usually about twice the cost of pressure treated lumber but only half as much as redwood.
Similar to cedar, these towering giants also have chemicals within their foliage and bark that make them resistant to fungal disease and insect infestation. Redwood’s internal cell structure also allows them to hold large amounts of water and air in pockets, so it works well for insulation and thrives in high-moisture areas. Redwood is famous, and expensive, due to its rich red color. Left untreated, through stains and sealers, the wood will turn to dull grey. This material is also only typically used on exposed portions of structures due to its cost, nearly four times as much as pressure treated lumber.
Cypress is found in common and premium grades, localized mostly in the Southeastern U.S. It’s a tan, reddish color, somewhat lighter than redwood, and is equal to redwood and cedar in its resistance to insects and rot. Cypress is typically used for both structural and ornamental purposes but it’s certainly not a cheap material. While less expensive than redwood and cedar, cypress is really only affordable if you live in the Southeast – the farther you are away, the more expensive it becomes.
- Pressure-Treated (PT) Wood
With a more pronounced grain than cedar, redwood or cypress, PT lumber is made mostly of southern yellow pine, and occasionally fir. PT wood is most commonly used as the structural material for projects and occasionally with the right stain, can be used as the decorative material as well. The wood is treated with chromated copper arsenate (CCA) which is used as an insecticide/preservative, as well as simple water repellant. Arsenate has been reported as potentially toxic to humans and animals and it is advisable to determine the type of treatment was used before purchasing the lumber. Less toxic, chemically treated lumber is now available that doesn’t contain arsenate, but is slightly more expensive compared to the bargain price of PT lumber. When working with PT lumber, of any kind, it is recommended to wear gloves and a dust mask.
- Tropical Hardwood
In the past ten years, tropical hardwoods have become more abundant, but still remains one of the most expensive building materials, by far. The reason for the added cost is due to the shipping costs and their durability that eclipses both redwood and cedar. These hardwoods have a life expectancy of 40 years, minimum, and are resistant to insects and decay. Other than the cost, other drawbacks include: most tropical hardwoods need to be predrilled for fasteners and there are major ecological concerns as to the harvesting of these materials.
It’s a good idea to check out the local building codes for your area before starting a project. No matter what type of wood you decide on, it’s important to take into consideration the size of the structure, use, climate, and soil type before building any structure.