Garage Door Header Span
Notches on the outer thirds must not exceed 1 6 of the width of the board.
Garage door header span. Tables providing size selections for various beam spans and loading combinations for southern pine dimension lumber and southern pine glued laminated timber are available for the following applications. Both headers and girders are beams that are oriented horizontally and transfer load down to walls piers or posts. Window door garage door headers supporting roof loads only. Most door frames that are 4 feet wide or less require a 2 by 6 header.
When in doubt use 2 by 12 inch headers. Measure the width of your door frame. To our knowledge no additional testing has been done to justify continuous headers over multiple garage door openings. Portal frame details within the irc specify simple span headers with a maximum finished opening width of 18.
Their is no notching permitted in the center third of any beam.