Q We are replacing all of the doors in our house and I am looking for information on the easiest way to install a pre-hung door jamb.
A Most interior doors (excluding bi-fold doors) are pre-hung assembled or knock-down ready to assemble. A pre-hung door (rough stud opening) must be installed to allow for shimming tolerance, this is required for both sides and the top. The rule of thumb is one inch wider than the door frame.
This is to allow for any shrinkage or twisting in the rough stud opening. If your door is the knock- down-ready-to-assemble type, put the unit together following the instructions.
You will find that you can assemble for either right hand or left hand hinge, swinging in or out of the opening.
Apply a piece of 1"x2" across the door at the bottom (right jamb to left jamb) to hold the door in the front plumb and square. Set the door in the opening and using a square and level shim with cedar door shims and fasten with nails. Start with the hinge side first then the others, shimming where required top and side. Allow for clearance under the door.