A wood beam is a structural support made from wood. They are most commonly used in wood frame structures like small houses, although they can be used in other types of construction as well. Both sawn lumber and engineered wood products are used to make beams, with engineered lumber having some distinct advantages including greater resistance to warping and twisting when it is well made. Contractors and architects are involved in decision making about the kinds of beams to use in a structure and how to install them.
Beams are designed to resist bending when stressed by weight or forces like high winds. They are included in structural elements like floors and roofs to distribute the weight of the structure and provide support. Historically, wood was the most common construction material in many regions of the world and solid wood beams were a preferred method of structural support.
The type of wood and size of the beam both play a role in how much weight a single wood beam will be able to bear. Dense, close-grained woods tend to be preferred because of their increased strength, as well as resistance to insects and rot. The wood beam can be cut in a solid block, I, or H shape, depending on the needs of construction. In some cases, multiple pieces of wood are stacked and bound to create a single beam. The wood needs to be fully cured before it can be used, as green wood will warp and twist once it is in place, compromising structural integrity.
In the case of engineered wood products, the wood beam is carefully calibrated to determine how much pressure it can withstand. These beams can be used as soon as they are finished, as they do not need to sit and cure. They tend to have a more predictable performance, as the wood is not flawed with knots, fine cracks, and other issues known to occur in sawn lumber. Engineered wood can also be fabricated in a variety of shapes to accommodate special building needs.
In the design phase of a structure, architects will determine what kinds of materials need to be used for the structural supports. There may be aesthetic concerns in cases where supports will be exposed, and in some cases, false wood beams may be installed over or around beams made from other materials like concrete and metal. A false wood beam is typically lightweight and may be made from veneers rather than solid wood.