Wood beams are most commonly found in post-and-beam construction, but are sometimes necessary in more conventional stud framing or in remodelling projects. In simple terms, a wood beam is a large, horizontal structural unit used to span a large distance. A beam is often left exposed so that it becomes a visual element, both inside and out.
Solid Milled Beam
This is simply the old-fashioned exposed structural timber crafted from one piece of wood. Solid beams can be found in old barns, western haciendas and occasionally spanning a doorway or large opening in a modern house. They are usually milled or hand-hewn into a four-sided structural piece. In some older buildings, a wood beam can be quite large, but today their use is somewhat diminished because of cost.
A pole beam is simply the trunk of a tree from which the bark has been removed. Pole beams are rarely used today, and may not be allowed as horizontal structural members by some building codes. Structural pole beams are most commonly found in log-cabin and adobe construction.
Laminated Wood Beams
Laminated wood beams are an effective way of taking advantage of modern building materials to make stronger beams with smaller pieces of wood. A laminated beam is built from several framing pieces (i.e. 2-by-6s, 2-by-8s or 2-by-10s) that are glued (with construction adhesive) and nailed or screwed together. In most cases, a layer of plywood is fitted between planks. Most laminated beams consist of three pieces of framing lumber separated by a 3/8- or 1/2-inch piece of plywood. An exposed beam made in this manner will need to be covered with wallboard or wood trim.
Engineered Beams and Joists
Engineered wood beams and joists are another way of using lesser wood materials to create a structural unit that can work as a beam. Engineered wood is a name applied to a finished wood support unit that very much resembles a wooden I-beam or in some cases a wooden truss. These units were originally designed to be used as beefed-up floor joists (technically speaking, a floor joist is a kind of beam), but when two or three of these units are placed side by side, they will act as a very strong and functional support beam. Again, this piece needs to be covered with trim if it is used in an exposed location.