How to Cut a Hole in a Load Bearing Wall for a Window

Remove the interior wall surfaces and insulation within the wall using the pry bar. Measure and mark the width of the rough opening on the bottom plate of the wall. Contact the manufacturer for their recommended specifications for the rough opening. This measurement is usually 1 inch wider than the actual dimensions of the window to be installed. Mark the location of the jack studs, studs to support the window header, and the king studs, studs to support the main load, next to the outer edge of the rough opening.

Measure the distance between the top and bottom plates of the wall. Cut 2-by-4s to this length to create the necessary number of king studs. Place them vertically between the top and bottom plates and nail them to the bottom plate at a 60-degree angle -- called toenailing -- with 10d nails. Verify that the studs are plumb with a spirit level; then toenail them to the top plate using 10d nails.

Measure from the floor to the height of the rough opening and mark the king stud at this point. This marks where the bottom of the header rests. Measure the height of your header. Measure and mark where the top of the header fits against the king studs. Extend both marks across the wall to the opposite king stud. Measure and mark the height of the window unit towards the floor from the bottom header line. This is the location of the sill.

Set the circular saw to its maximum depth setting and cut through any studs between the king studs at the lines marking the top of the header and the bottom of the sill. Knock out the cut stud sections with the pry bar.

Cut two jack studs to reach from the bottom plate to the bottom header marks on the king studs. Nail the jack studs to the king studs using 10d nails every 12 inches. Nail the header to to the king studs , jack studs and the cut studs above the header. Nail together two 2-by-4s and nail them to the cut-off studs at the bottom of the window. Now the wall is fully supported and you can cut through the exterior of the wall.

Drill holes at the corner of the framed opening from the inside of the house. Push nails through the holes to make their location easily visible on the outside
Using a level, draw straight lines connecting the position of the nails. Cut along the lines with a circular saw.

If the exterior is wood, knock out the cut wall sections. If the wall is stucco, break up the wall within the cut section with a masonry hammer until the metal laths are visible. Cut through the metal lath with aviation snips. Pry the cut-out section from the wall.