Pre-Hung Exterior Doors
One of the first home improvement projects I tackled was replacing the screen door on the garage with a new pre-hung steel door. The screen door lacked a lock and was so ill-fitting that even when I added a lock, it could still be forced open with little effort. Not only that, but the glass panes made it real easy to look inside the garage.
Replacing the door should have been easy, but it wasn't. I wanted as wide a door as possible, which led to removing the existing wood frame. I also did not want the hassle of special ordering a custom size door. The existing door was 82 inches high instead of the standard 80, which meant that I was going to have a gap to contend with at the top of the new door.
With the help of a friend, I removed the screen door and the existing wood frame. The garage is block construction and the frame was impaled on large nails that were embedded in the block. I cut the nails off using a reciprocating saw.
We then installed the new framing to which the door frame would be attached. We used pressure treated deck boards for the frame: one board for each side and three boards for the top (to fill the extra height). The top-most board was cut to the width of the doorway (less a quarter inch to allow for adjustment). The second and third boards were cut shorter by the thickness of the two side pieces to allow for a sort of rabbet. The top three boards were sandwiched together with screws and the side pieces were attached with screws driven through the top board.
The block of the garage is 8 inches deep. Our door frame assembly was about 5 inches deep. We set the frame back from the edge of the outside of the garage by the depth of a 2 x 2 piece of lumber. Our frame assembly was attached to the block using concrete screws: 5 inch long screws for the top boards and 2" long screws for the 1 inch thick boards at the sides.
With the easy part out of the way, we were ready to install the new door. I found it to be an extremely frustrating undertaking. It is possible to hang a door without a helper, but most do-it-yourselfers will find that a little assistance is required. Word of advice: shake hands and apologize in advance for all the swearing that you are about to do.
We positioned the door in the opening. The rough opening has to be about 2" wider and higher than the door to allow room for adjustment. In order to operate properly, the door frame has to be square and plumb.
Square: The door frame has to be square to allow the door to close properly and securely, maintaining a good seal with the weather stripping. The door should swing smoothly and remain in the open position.
Plumb: Front to back and side to side.... can be checked using a plumb bob, or use a level to measure vertically.
We actually got very lucky as the hinge side of the rough opening was perfectly vertical. We were able to screw the door frame to that without using any shims. We shimmed around the rest of the door frame and screwed it to the rough frame. I then used expansion foam to fill the gaps.
I have been told that the proper technique is to shim the corners first so they are square. Then either the hinge side or the latch side is shimmed and screwed into place (there is some debate as to which is better), and finally the top and third side. Frankly, I have since installed several other doors and I did each one differently.
With the door in place, I used 2x2 and 2x4 lumber to bring the frame out flush to the exterior of the garage, and used quarter round moldings for the transition between the door frame and the new frame. Inside, I was a little less fussy and just used 1x1 nailing strips to come out flush to the interior of the garage.
All gaps in the trim were filled with paintable caulk to prevent water penetration. Another precaution that we took to prevent water damage was to leave a small space between the ground and the bottom of the rough frame. This gap was filled with expansion foam and caulk.
The door and frame were painted to match the colours of the stucco and trim on the garage. The finished product, if I do say so myself, looks pretty good.
Advantages of Metal Doors
Insulated metal doors offer higher R-Value than similar wood doors.
Any dents and dings can be easily repaired using auto body filler. Sand the damaged area down to the bare metal. Apply the filler according to the instructions. Prime and paint.