Age Restriction On Lumber In Trusses
Question:
I would like to know if there is an age restriction on wood trusses. How long after production are they safe to use? The trusses in question are at least three to four months old. Are they still safe to use? They have not been covered the entire time and are showing signs of age.
Answer:
There are many factors that affect the strength, which in turn affects the life expectancy, of wood. One of the main factors regarding strength is the moisture content.
Things you can look for to determine if the trusses are over-exposed to moisture: the teeth in the metal plates will actually start to pull out of the lumber, fungus and mold will grow on the trusses, and the truss plates may begin to show signs of rusting, starting with white rust that will eventually migrate to red rust. Anytime you see red rust, it is time to take a much closer look at the trusses.
In the event of long-term storage, trusses need to be protected from the environment in a manner that provides for adequate ventilation. If tarpaulins or other materials are used, the ends need to be left open for ventilation. Plastic is not recommended, since it can trap moisture. When storing the trusses horizontally, blocking needs to be used on eight to ten foot centers, or as required, to minimize lateral bending and moisture gain.