As long as you’re careful to buy a pre-hung door that matches the exact specifications of the one you’re removing, all it takes to install a new door is to carefully remove the old jamb and replace it with the new one.
Most doors come with a manual to walk you through that process. But we’ll offer a few door installation tips and tricks that you won’t find in the manual right here.
Tip #1: Avoid Drywall Damage When Taking out Trim — The first step in taking out the existing door jamb is to remove the interior trim that surrounds the door. You need to pop off this trim carefully, so you can reuse it once the new door is in place.
The best way to remove this trim is to pry it up carefully with a pry bar, working your way along the trim. To prevent damaging the drywall, stick a putty knife behind the pry bar as you work (Fig. 1).
Tip #2: Cut It out Quickly with a Recip. Saw — Once the trim is removed, the easiest way to remove the jamb is with a reciprocating saw. Just equip the saw with a blade rated to cut through nail-embedded wood, insert it between the jamb and the wall, and cut carefully down each side of the jamb (Fig. 2). Then repeat the process along the top of the jamb.
Tip #3: Chisel Away the Old Caulk — If your existing door was well-installed, there’s probably a bead of old caulk around the exterior of the door jamb to seal it from the elements. Before you pull the door, you need to dig out this caulk using a hammer and an old chisel (Fig. 3).
Tip #4: Take out the Old Door — The old door jamb should now slide out smoothly (Fig. 4). If it needs a little extra prompting, you can work your way around the gaps with a pry bar to pull loose any old nails or glue that’s still hanging on.
Tip #5: Install the New One — With the old jamb removed, take a few minutes to clean up any debris (nails, glue, etc.) that remains in the opening. Then run a bead of caulk under the threshold of the new door, and slide the new jamb into place (Fig. 5).
Tip #6: Shim It Square & Plumb — Perhaps the most time-consuming part of the whole installation comes next, and that’s shimming the jamb square and plumb. There’s really no big trick to this process; you just want to use a long level to check every surface of the jamb, and add shims where necessary to make the level read square or plumb. Once the door is shimmed properly, secure the shims with screws (Fig. 6). Then snap or saw off the shims, so they rest behind the surface of the jamb.
Tip #7: Finish Up in Style — Now all that’s left are the finishing touches, such as applying a fresh bead of caulk around the exterior of the jamb (Fig. 7). You may also need to adjust the sill and install a long screw in each hinge for support and security.
Have a nice weekend,
Online Editor, Workbench