Factors
Several components determine the single point weight capacity of an individual wood beam, including the total dimensions of the beam. For example, a 14-foot beam will have a different capacity than a 16-foot beam. Builders must also consider the total weight to be distributed across the beam, points out the American Wood Council.
Additional Considerations
Depending upon the grade and species of lumber, one beam may perform better than another. The American Wood Council suggests consulting with the lumber supplier, when possible, to determine the origin and grain of the beams.
Calculating Single Point Weight Capacity
Once you know the length of beam and total load, determining the single point weight capacity proves rather simple. Generally, you can find out the capacity by dividing the total load bearing weight by the length of the beam. For example, a 9-foot-long beam span, requiring a total load bearing of 680 pounds, has a single point capacity of approximately 75.5 pounds.