How to Install Headers Above Windows

By Michael Straessle

A header above windows is necessary to strengthen the wall above the window and also keeps a lot of weight off of the window. A header for a window is the most crucial part of the wall construction to accept windows. It also gives the horizontal trim the support it needs. For the sake of this article, we will build and install a header for a 30-by-36-inch window in a wall with studs on 16-inch centers.

Things You'll Need

  • Hammer16d box nails2 studs (2-by-4-by-92 5/8)Carpenter's level3 pieces 2-by-4-by-35 1/8-inch lumber1 piece 2-by-4-by-32-inch lumber2 pieces 2-by-4-by-38-inch lumber2 pieces 2-by-6-by-32-inch lumber1 piece 5½-by-32-by-½-inch plywood3 pieces 2-by-4-by-12 inches

Step 1

Install the studs to the top and bottom plate 32 inches apart. Place the carpenter's level on each to be certain they are plumb. Next, place one of the 2-by-4-by-35 1/8-inch lumber against one of the wall studs in the window opening. Secure it to the stud with the box nails. Repeat this for the opposite stud. These are called "cripples." To learn more about sizing a window opening, see "Sizing a Rough Opening for a Window" in the reference section.

Step 2

Place the 2-by-4-by-32-inch lumber on a worktable. Measure and mark the center; place the remaining 35 1/8-inch 2-by-4 against it with the mark in the center. This will form a "T." Secure the two pieces with the box nails.

Step 3

Place the "T" in the window opening so that the 32-inch top rests on the two 2-by-4s from Step 1. Secure the "T" to the cripples with the box nails. Also, secure the vertical 2-by-4 of the "T" to the floor plate of the wall.

Step 4

Place the two pieces of 2-by-4-by-38-inch lumber on top of the "T." Secure them to the wall studs with the box nails.

Step 5

Next, place the ½-inch plywood between the two pieces of 2-by-6-by-32-inch lumber. Secure them with the box nails. This is the header.

Step 6

Place the header on top of the 38-inch pieces from the previous step. Secure it to the studs on the left and the right side of the header. Next, place the 12½-inch 2-by-4s between the header and the bottom of the top plate. Secure them with the box nails.

Tips & Warnings

  • Some codes may require horizontal blocks between the studs that make up the width of the window opening and the wall studs.You can substitute drywall screws for the box nails.
  • Do not leave nails in reach of small children.Do not allow nail heads (or screw heads) to be above the surface of the lumber inside the rough opening of the window.