The first thing you will need to do is to gather your installation tools.
You will need:
- nail gun (one that shoots small trim nails)
- level (I prefer a 6ft level)
The shims I use come in small packs about 8 inches long and 1 1/2 inches wide, which I cut in half.
The opening of your doorway should be 2 inches wider and 1 1/2 inches taller than the frame, not including the casing (the part you see on the wall around most doors) of the new door to be installed.
This is the door I will be installing.
The frame is what is called a split-jamb, so it needs to be separated. It it held together on each side by two blocks of wood which can be seen below.
The nail in the picture below is what keeps the door from swinging loose before installation. This should be removed just before you are ready to put the door in the opening.
You want to set the door up off the floor just a bit. To do this, I place a block of wood (approximately 3/8 inch thick) on the floor underneath the hinge side of the door.
Now you are ready to place the door into the opening.
Next, place your level against the hinges and lean the door slightly right or left, as needed, until the bubble is centered between the lines.
I like to use a 6 foot level because it will reach all three hinges simultaneously, resulting in a more accurate reading on your level.
At this point, you need to use your nail-gun, screws, or whatever you choose to fasten the door with, and fasten it securely. I typically nail twice behind each hinge, and once in between the hinges.
Make sure the gap along the top of the door is consistent, and nail the top.
Now you can do the same along the latch side. Occasionally the gap right at the top edge of the door will be to small and will need further adjusting. That is the case on this door.
Use a hammer to tap the frame until the gap is consistent. It would be best to use a block of would to hammer on to prevent from denting the frame.
Now you are ready for the other side of the door. Pull the door shut and check to see if the door contacts the frame the whole way down. In this case, the door closes tight at the top, but has a 1/4 inch gap at the bottom.
The door needs to be shimmed in place, it is best to start with the hinge side. I start on the bottom. To correct the gap where the door contacts the frame, pull the frame slightly and nail it. In this situation, the bottom of the door does no make contact with the frame, so I need to pull the frame next to the bottom hinge (almost as if you were twisting the whole frame) and nail it twice below the hinge, and once above.
Continue making adjustments and nailing the frame (always use shims where you nail) until the door fits nicely against the frame.
You can see here I shim behind each hinge. I also shim in three places on the latch side of the frame.
Now you are ready to install the “split” part of the split-jamb door.
Nail it through the door stop, at the same place you previously shimmed the door.
You also need to nail the casing all the way around.
In this case, the corners of the casing do not fit very well. To remedy this, slide a shim behind the joint of the casing until the gap is closed.
Now your door installation is complete:D