Pre-hung doors are. Tom Silva of”This Old House” states that pre-hung doors have sped up the setup procedure by removing several steps, such as assembling the door jambs and hand-cutting that the mortises where the hinges are placed. When you’re installing a pre-hung doorway in an older home that includes plaster walls, then you can find that you need to purchase custom-built doors, or add framing so that the door can match.
Place a level. Place shims underneath the level if the threshold is not flat and adjust them until it’s level. Nail the shims. Trim the excess.
Measure the distance from the bottom of the side jamb on the prehung door frame to the middle of every door hinge. Transfer those dimensions to the side jamb in the wall framing and indicate every place, measuring up from the ground. Place the marks on the side that where the door hinges will be.
Hang a plumb bob next to the side jamb in the top of the door frame. Measure the distance between the side jamb and the string of the plumb bob at every mark you made on the jamb. Place two shims that are overlapped at the place of the hinge where the distance between the side jamb and the plumb bob series is the narrowest. Till they are thick where they float, move the shims, and nail them.
In which the other hinges are being installed, nail doubled-up shims into the side jamb. Before nailing the shims correct them so that the gap between the shims and the plumb bob string matches the initial pair of shims and the difference between the plumb bob series that you just installed. Trim the excess material in the shims with the utility knife.
Place the prehung door to the wall opening by leaning the doorway toward your top and placing the base of the doorway on the threshold. Push on the edge of the doorway into place in the wall. Keep the door closed when doing so.
Drive an 8d finishing nail partway through the casing of this prehung door frame and to the wall 3 inches below the top of the frame. Check the door casing for plumb (vertically straight) by holding a flat against the side. Adjust the doorway inside the framing until it’s by sliding shims to the gap between the wall and the prehung door frame plumb. Secure the door set up by forcing 8d finishing nails through the door casing and to the wall at the location of every door hinge. Trim the extra shims together with the utility knife.
Measure the distance between the edge of this prehung door and the wall framing every few inches along the doorway. If the gap is wide or differs at any point, push it up against the top of the door frame using the side jamb on the latch side of this doorway. Drive an complete nail through the casing near the edge of the doorway.
Using a nickel for a guide, check the gap between the casing along with this wall’s side. The gap should be approximately as thick as the nickel. If necessary, correct the casing and nail it with 8d finish nail in place.
Push 8d finish nails through the casing on the latch side of this doorway each 16 inches.
Immediately and shims between the wall frame and also the latch-side casing a couple inches below the top of the doorway above and below the strike plate. Trim the extra shim material together with the utility knife.
Eliminate at the hinge on the region of the hinge that is connected to the casing, not the part connected to the doorway. Replace the middle screw with a screw that is 3-inch. This screw is long enough to reach the wall frame, which prevents the door from sagging.
When removing the door, patch any plaster you ruined. Remove any loose bits of plaster, and fill the holes with joint compound. Smooth the surface of the patch together with the putty knife. Allow the patch to dry.
Set the split jambs into place on both sides of the doorway. The split jambs will be the trimming to the door. A single split jamb’s edge and another has a tongue and a groove, respectively. Join the jambs by inserting the tongue.
The side jambs into the wall each 18 inches around the perimeter of the doorway with 8d finish nails. Push 8d finish nails through the door stop and into the wall framing above and below beneath each door , only the striker and and near the top and underside of this latch jamb.
If it wasn’t pre-installed install the door hardware. Screw the latch plate into the side of the door frame inside the place carved out for it (that the mortise). Slide the bolt for the door latch into the hole at the doorway, as you attached the plate into the door frame and attach the plate for the bolt into the edge of the doorway. Attach the door knobs into the bolt and screw them.