Trees large enough to make traditional solid wood beams have become more rare and expensive. As a result, many construction projects use beams made of laminated wood. By varying the grain direction, one advantage of laminated beams is that they are actually stronger than solid wood beams.
Laminated beams can be used to span low- to moderate-weight roof areas and as vertical support columns or pillars. Although homemade laminated beams may not be able to support as much weight as engineered beams because of the simpler tensioning and glue laminating material, they can work very well in many situations.
Making laminated beams can be a good alternative to finding large, solid wood beams. When considering whether or not to make beams, look at your available tools. You will need a number of clamps at least the thickness of the final beams and wood glue. The number of clamps will depend on the length of the beam. Place clamps at 6- to 12-inch intervals.
You have several options for wood for your laminated beam. One option is to use strips of plywood glued together. By using strips of plywood, you won't have to worry as much about grain direction. However, many people make heavy laminated wood beams from 2 inch by 4 inch lumber. When using solid lumber, try to place the lumber in the beam so the grain creates a criss-cross pattern throughout the beam. This will help with your beam's structural strength.
Glue & Clamp
To make your laminated beam, apply a thin layer of wood glue or epoxy to each face of the wood in the beam. Lay the wood and straighten the sides. Clamp the wood tightly and allow the wood to cure. If the beam will be exposed, plane the sides of the beam to remove uneven wood and any glue that was squeezed out during clamping.
Things to Watch Out For
After installation, the natural process of the wood drying can result in cracks, or "checks" in your beams. In most cases, these naturally occurring cracks will not affect the structural integrity of your beam. However, if you have cracks on the bottom face of your beam that are not parallel to the grain, have the beam checked by an engineer. If side cracks are more than one-third of the length of the beam and more than one-third of the beam width, the beam may need to be inspected by an engineer. Splits on the ends of beams more than half the depth of the beam may also need inspection.
When installing glue-laminated beams, try to avoid drilling large holes or creating notches in the beams. These can weaken the beam at the point of the holes or notches. If you must notch or drill a hole through the beam, try to drill on or notch as small an area as possible and do so on the non-tension side of the beam.