Here's how to install top-quality, solid-core doors that weigh 100 pounds or more.
The jamb assembly is held in the opening between scraps of strapping. A temporary spreader near the bottom maintains a uniform finish opening. The author first cuts the side jambs to compensate for an out-of-level floor.
With shims at the header pinning the side jambs to the floor, the author screws the top of the hinge jamb to the framing.
A door-length level clamped to the jamb provides a reference for both plumb and straight, leaving hands free to insert and adjust the shims.
The author shims the hinge jamb first, directly behind hinge locations and at top and bottom.
A finish nail through the jamb prevents the shims from loosening. They'll split readily around the nail if further adjustment is needed.
Plywood clips keep the jamb from moving out of the wall plane when the retaining straps are pulled.
The author initially installs only the outlying screws so that he can adjust the tapered shims in or out when finetuning the jamb.