Before you actually begin making a window opening, there is one step that you absolutely need to do. That step is to go out and purchase your new window, and familiarize yourself with the directions. This will give you some additional specific steps that you may need to follow in order to properly install your window. Once you have done that, you are ready to begin making a window opening.
Before you begin, two notes of caution. Since you will be cutting into your wall you need to be pretty careful. Remember that all exterior walls are load bearing, and as such you will need to provide some extra support to ensure you don't cause any damage to your home. In addition, be very careful when you cut into the walls since you do not want to accidentally cut into any power cords or wiring. In fact, it would be best if you turned off all power to that section of the home before you begin, in order to avoid any accidents.
- Pry bar
- Reciprocating saw
- Tape measure
- Spray paint.
- Stud finder
- Circular saw
- 2" x 6" x 36" piece of wood
- 8d nails
- 16d nails
- Utility knife
- Drop cloths
- 2" x 4" lumber cut to measurement
- Jack posts
- Remove any trim. If the interior of the wall that you are adding the opening to happens to have any trim on it, you will need to remove it. Do this by using a pry bar or hammer. Before you actually begin removing the trim though, make sure that you have placed some drop cloths down to protect your flooring. This is also the time when you should make sure that you have turned off any power that may be flowing through this particular wall. Do this at the breaker box by throwing the switch. Leave a note saying to leave the power off in order to avoid any accidents.
- Make your mark. Place a mark on your wall where you want the window to go. Use this mark to help guide where you will be placing the window itself. Before cutting out any of the wall, make sure that you are wearing your safety glasses and dust mask. Use a drywall knife and begin removing the drywall from the area that you have marked off. Once you have cut an initial opening, you can continue to remove the drywall by using a circular saw. Just make sure that you set the depth properly, or you can accidentally cut some wiring. Remove the insulation, and drywall, and mark the studs and opening with some spray paint to ensure that you know where you will be cutting the final opening. Continue demoing the rest of the interior of your wall.
- Add some support. If you are cutting into an exterior wall, or a load bearing wall, you will need to add a little additional support. Do this by locating the joists in the ceiling nearest to your opening. Once you have located them, brace the area with some jack posts and a 2 inch by 6 inch by 36 inch long piece of wood. Center the jack and wood on the joist, and extend the jack until you cannot move it. Be careful that you do not damage the ceiling.
- Remove the studs. Remove any studs that are in the area where you will be installing your new window. Cut the bottom and top of the studs out with the help of a reciprocating saw, and set the wood aside. When cutting the wood, cut it as near to the top and bottom as possible.
- Plan your new framing. Begin planning your new framing by measuring three inches from the where the opening will be, and drawing a line. This line will mark the outside edge of your king stud you will be using for the opening. Mark an area just to the left of this for your trimmer (or jack stud) as well.
- Add studs and headers. After having made sure that your king studs are cut to length, toenail them into place. Use four 8d nails at each end to hold the lumber in place. If you will be face nailing, then use 16d nails. Once the king stud is in place, add a jack stud next to the king stud. This jack stud should be long enough to go from the soleplate (bottom of the framing) to the top of the rough opening. Nail this to the king stud. Repeat this on both side of the opening. At the top of the jack stud, place a header. For load bearing walls, you will want to use a built-up header.
- Add a rough sill and cripple studs. Mark where you want the bottom of your rough opening to be, making sure that the marks are as level across the jack studs as possible. Measure from one mark to the other, and cut a rough sill to fit between those marks. Wedge it in place, and make sure it is level. Once the rough sill is level, toenail it into place. Underneath this sill, add some cripple studs (small jack studs) that will reach from the bottom of the sill to the soleplate. These should be placed every 16 inches (centered on the middle of the window).
- Remove the outer wall. Remove the final outer section of the wall by first drilling a lead hole. Place a reciprocating saw into this hole, and continue to cut out the out wall of your rough opening. Discard everything that you remove properly.
You have now finished making the opening for your new window. All you need to do now is install the window itself, and refinish the walls.