The Right Header for Every Wall
Several code-approved options beyond the standard double 2x12 save material and energy.
Synopsis: Double 2×12 headers are still the standard for window and door openings, even though the IRC lists other options for headers that save lumber, minimize thermal bridging, and save space for insulation. Builder Mike Guertin provides a comprehensive look at header design and discusses how to figure out the right-size header for a given span. He also discusses several alternative designs to the double 2×12 and when they are appropriate: rim-board header, box header, and using a flat 2x instead of a header.
When I started framing houses in the late 1970s, the standard header for almost any size window and door opening was a double 2×12 with a 1⁄2-in. plywood spacer to bring the header flush with the stud edges in a 2×4 wall. When the header is pushed hard to the double top plate of an 8-ft.-high wall, its bottom sets up window and door head jambs 6 ft.…