Building Headers

One of the most important components in homebuilding
construction is the header. When framed in a wall, headers
span the spaces above doors and windows and bear the weight
of floors, ceilings and roofs above them. They are also used
in interior walls for doorways and where more open spaces
are desired between rooms. 

Depending on the bearing load above an opening, headers can
be constructed of 2x4's on up to 2x14's or microlams. In a
standard 2x4 wall these elements are doubled up with a 1/2"
spacer between them and nailed together with 16d nails on
both sides. In homebuilding, the most common size headers
are usually 2x10 or 2x12. 

Most headers for doors and windows are cut 3" longer than
the width of the rough opening. In a standard wall, a 2x10
or 2x12 header is usually nailed to the top plate. Next,
2x4's are nailed to the top plate and into the ends of the
header. Next two by (2x) cripples are nailed inside these
studs and under the header. These 2x4's are cut to the
height of the door or window. If it is a window, a 2x4 sill
is nailed to the bottoms of these cripples. The cripple is
then continued below the sill to the bottom plate. This
transfers the load from above the window to the floor and
onto the foundation. 

For an example, lets say we are building a header in a 2x4
wall for a 36" wide rough opening. Take 2 pieces of header
material (2x10, 2x12 etc.) and cut them to 39". This allows
for the thickness of the 2x4 cripples(3"). Next cut a piece
of 1/2" plywood slightly less than the width and length of
the header. This is to keep it from hanging into the opening
and to keep it away from framing members. Sandwich the 1/2"
plywood spacer between the header material. Make sure to
crown the 2x's with the crown up. Before nailing the header
pieces together make sure the ends and bottom are flush.
Nail together with 16d nails, 3 nails top to bottom, 16
inches on center from one end to the other. 

Rough openings are usually known well in advance of the jobs
start. Headers can be built before any framing even begins.
When building headers the use of a framing nailer can make
the task go faster and save wear and tear on ones arm. 

Mike Merisko (C) 2006 www.sawkerfs.com