"Lumber" is the term commonly used to refer to wood after it has been felled. Different types of lumber can be used for many different purposes, such as home construction, furniture building, and wood-fire fuel. Some of the most common types of lumber include dimensional lumber, softwood lumber, hardwood lumber, and treated or engineered lumber.
Dimensional lumber refers to any type of wood that has been smoothed and cut to meet standardized sizes. Many building projects will require dimensional lumber, since it ensures that the length, width, and depth of each piece will be exactly correct. Dimensional lumber is often available at hardware stores or from lumber supply companies. The standardized sizes may vary by country, but tend to be consistent throughout a single region.
Softwood lumber comes from trees that are known for their absorbent wood and straight grain. Softwoods are generally less expensive than hardwoods, as they are easier to grow and tend to have fewer defects. Some common types of lumber from softwoods include pine, redwood, fir, and cedar. Most types of lumber in this category have a red or yellow appearance, and are commonly used for home construction.
Hardwood lumber tends to be more expensive, but usually features beautiful colors and natural resistance to moisture. Prized for art and furniture making, hardwood trees are somewhat more difficult to grow, and tend to provide less usable lumber per tree than softwood trees. Most species used to create hardwood lumber are deciduous, and include mahogany, ash, cherry, and teak. Since these types of trees tend to be more rare, environmentally-conscious buyers may want to look for hardwood products that are grown on tree plantations or through sustainable methods, so that use will not damage the population of wild trees.
Lumber can be put through a variety of chemical and finishing processes, creating treated or engineered products. Some types of lumber may be laminated, creating a seal against moisture, fungus, and insects, which can be very useful for wood that will be used in an outdoor environment. Planks may also be put through a veneer process, which dyes the wood to a specific color or creates a base coat for painting or staining. Engineered lumber refers to wood that has been finished or reinforced for construction purposes; for example, some lumber may be glued together to increase the load-bearing capacity of the finished piece. Other engineering techniques allow the creation of planks that are several times longer than common standardized sizes, for use in large construction projects.
