As the span of a beam increases, the amount of weight it can carry is reduced. Engineers, architects and builders calculate the necessary size of a wood beam using span charts.

I’ve looked at lumber span tables, and regular lumber doesn’t seem to be able to do what I want to be done. What are my options, and have you ever solved this problem before?

Window Span: 5 feet, 9 Inches For even wider window spans of 5 feet, 9 inches or less, use two two-by-eight pieces of lumber.