Enclosing your porch with double pane windows is a fairly easy task if you know how to work a tape measure -- correctly. Enclosed porches provide an enjoyable place to relax in all seasons as well as adding value to your home.
Measure the area you want to enclose to determine how many and what size windows you will need and also how much lumber is necessary for the project. Check your measurements with your window and lumber supplier.
Measure and cut your bottom plate. Run a bead of contractor's glue down the center of the plates. Screw or anchor your bottom plate into the porch floor, then measure and cut the top plate and attach this plate to the ceiling. Double the bottom plate using blocks in between the upright studs for more stability . If you are setting your plates for the frame on concrete you will need a power hammer or concrete nail gun.
Measure from the bottom of the top plate to the top of the bottom plate to obtain the length of your upright end post (stud). Cut the stud and put it into place nailing it into the plate at a 45 degree angle. Check it with a level to ensure it is aligned from top to bottom and attach it the same way you did the bottom and top plates. Now measure and cut the other upright stud for the far end, and put it into place.
Measure your bottom and top plates from one end to the other, and mark the center of both of them with a pencil. Take the measurement for the first window frame (based on the size of your window) and split the difference on both sides of the center mark, this is where the first upright stud will sit for the window frame . Add an additional 1/4 inch to your measurement so that the window frame will not be to tight for the window to fit into place.
Measure between the two uprights you have nailed into place for the first window, than cut the cross sections that hold the window in place. Measure the window to determine where it will sit in the frame. For example, you might want the window to be centered in the wall or you may prefer more space at the top or bottom of the frame. After window placement has been determined, measure from the top of the bottom plate to where the window will sit, placing a mark on the uprights on both sides. Place the cross section that holds your window between the two upright frame boards and nail or screw into place. Put one nail on each side to hold it and than check the cross section to ensure it is level than finish nailing the cross section. Do the same for the top cross section.
After the frame has been nailed into place, put the window in the opening to ensure a tight fit. There should be a slight gap on either side for adjustment. After the window is put in you can use wood shims to tighten the window up in the frame before you screw it into place.
Visually inspect your window frame for proper fit. In addition, cut and place short studs above and below the window at center to stabilize the frame and to have more studs to attach exterior plywood sheeting.