Posted on December 16th, 2015 by Aaron Presley
Wood has been an invaluable building material for thousands of years, but in certain situations, it is prone to decay, limiting its usefulness for many applications. Environments that are prone to moisture, that encourage the growth of bacteria or fungi or that harbor wood-boring insects are especially challenging for natural wood products. While other building materials, such as rock, concrete, aluminum or steel, may be used in place of wood in many inhospitable environments, they tend to be much more expensive and difficult to work with.
To combat the limitations of natural wood and make it suitable for use in more extreme environments, pressure treated lumber was developed. To create pressure treated lumber, intense pressure is used to force one of several different chemical compounds deep into the grain, providing protection from the elements, fungal growth, bacterial growth and pest infestation.
As a building material, pressure treated lumber offers several unique advantages over natural wood lumber, as well as other building products. Below are eight different advantages for using pressure treated lumber as a building material for your next project.
Natural wood left in moist or wet environments will soften quickly, allowing fungus, bacteria and other microorganisms to take root, slowly decomposing the wood. Pressure treated lumber uses one of several chemical compounds based on copper, which is a natural biocide, protecting it from fungus and other microorganisms that cause wood to decay in moist environments.
After treatment, the lumber can be used in a variety of applications, such as for decks that are constantly exposed to the elements, sill plates on potentially-moist concrete, or even as support posts for docks and piers, where the lumber will be constantly immersed.
Even with the slightest amount of moisture, many different types of fungus can attach themselves to wood and start to grow, sending their root structure deep into the wood to slowly decompose it. As the wood weakens, it can be preyed upon by other organisms, including insects and bacteria. Pressure treated lumber uses copper-based compounds, such as alkaline copper quaternary or copper azole, to prevent fungal growth. These are sometimes used in combination with other compounds that also provide insect resistance. The chemicals allow pressure treated lumber to be used in applications where it will be consistently moist, such as for buried posts or in basements.
In many areas, insects like termites and carpenter ants pose a significant threat to any structure built with wood. The insects can easily bore through the lumber, weakening it and eventually causing dangerous structural problems, especially when the wood is exposed and moist. The copper compounds in pressure treated lumber provide protection from insect damage, and additional chemicals such as borate or, less frequently, arsenic compounds, can be added to further discourage insect activity.
When pressure treated lumber is used effectively in the construction process, by placing it in areas prone to insect activity, it can also provide a barrier that protects the rest of the structure from insect damage, including untreated wood. Additionally, it can discourage other nuisance insects, such as cockroaches and spiders, from taking residence in the structure.
One of the most dangerous threats to wood-based buildings is fire damage. By employing the same pressure-treating process that is used to inject insecticides and fungicides into the wood grain, fire-retardant chemicals can also be added to create pressure treated lumber that is resistant to fire damage. Flame retardant lumber can be used in applications where the risk of fire is increased, such as lifting-prone locations or near fireplaces.
Pressure treated lumber is available in a wide array of sizes for different applications. For building purposes, it comes in the standard dimensional lumber sizes, such as two by fours, two by sixes or two by tens. For posts, it is available in a variety of square cross-sections, such as four by four or six by size, as well as round cross-sections. It can also be used for building decks, docks or piers,? or for lighting posts or utility poles. It is also available as planking for deck flooring or for siding, as well as in many other styles for more unique applications.
Compared to natural wood, pressure treated wood is more expensive. However, it is worth it for any application that requires resistance to water, microorganisms, fungal growth or insect damage. Compared to other materials that may be used in place of pressure treated wood, like stone, concrete, aluminum or steel, pressure treated wood is typically less expensive to purchase and install due to its ease of installation and use. Pressure treated lumber can be used in a number of indoor and outdoor locations where materials like steel would quickly corrode without a proper coating.
Compared to natural wood, pressure treated lumber will last far longer in any environment where it is exposed to the elements or consistent moisture. Its insect and fungal resistance also helps it to outlast natural wood, and because it tends to be denser that untreated wood products, it also has increased strength. Compared to other materials like concrete or stone, it is much lighter, and compared to materials like steel, it is resistant to oxidization.
Like other wood products, pressure treated lumber can easily be cut to size using a saw, and fasteners like nails will penetrate it easily. Drills can be used to bore holes through the wood easily, and routers can be used to shape it. Compared to products like steel, it is lightweight and can be easily maneuvered, and it does not require special techniques like welding to complete projects. With pressure treated lumber, almost anything can be built quickly and easily, with little or no experience.
Pressure treated lumber is a versatile and convenient building material for just about any project, from mounting a mailbox to building a full deck or an outdoor play-set for children. With its resistance to water, fungal growth and insect infestations, you can be sure that whatever is built with it will be extremely durable and will last for many years with a minimal amount of maintenance. Varieties that are fire resistant, and the new formulations that are far more environmentally-friendly than the earlier prototypes, can be used to ensure that your project is safe and healthy for the environment.