Determining Necessary Truss Height


How high would a truss have to be to span 33 feet 9 inches?


They are a lot of factors to determine how high a truss is. First is this a floor truss (flat) or a pitched roof truss? How much load will the truss have to carry? What lumber grades are available for the truss? What are the code requirements? So you can see there are a lot of factors that would determine the height of a truss. Here’s an example of how to calculate the height of a common shaped pitched roof truss. An approximate height of a pitched truss can be calculated with the following formula: take 1/2 the span and multiple it by the pitch. Then add about 4 in. for the top chord lumber. For example: a 33-9-0 (33 ft., 9 in. and zero 16ths) truss on a 4/12 pitch would be 33.75 ft. times 0.5 times 4 = 67.5 in. plus 4 in. = 71.5 in. or 5-11-8 (5 ft., 11 in. and 8/16ths).

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