In this video, This Old House general contractor Tom Silva cuts a new interior doorway.
1. Outline the new doorway's rough opening onto the wall with blue painters tape.
2. Use reciprocating saw to cut through drywall or plaster.
3. Cut the baseboard using the reciprocating saw.
4. Pull the drywall or plaster, and baseboard from the doorway opening.
5. Nail short 2x4 blocks under subfloor.
6. Set 2x4 sill plate to top of vertical blocks and nail in place.
7. Install a 2x4 header across the top of the doorway opening.
8. Assemble a single-rabbetted doorframe, then set the door into the frame.
9. Mark the hinge locations onto the side jamb.
10. Remove door from the assembled frame and rout the hinge mortises using a homemade template and router.
11. Square up the rounded corners of the mortises with a hammer and chisel. Repeat for remaining hinges.
12. Tap the hinges into the mortises and screw them to the sidejamb.
13. Fasten together the doorframe by screwing the head jamb to the side jambs.
14. Extend the subfloor onto the 2x4 sill by installing two ¾-inch-thick filler wood strips. Nail the strips to the sill.
15. Lay an oak threshold on top of the filler strips and nail it down.
16. Stand the assembled doorframe in the rough opening. Check the frame for plumb in two directions with a 4-foot level.
17. Slide wood shims behind the hinge-side jamb, then use a pneumatic finishing nailer to secure the jamb to the rough opening.
18. Hang the door and insert shims behind the opposite side jamb to create an even gap between jamb and door edge. Nail through jamb and shims with a pneumatic finishing nailer.
19. Use a sharp utility knife to score the shims protruding from the doorframe, then snap the shims off flush.
20. Install casings around the doorframe, trimming the baseboard, if necessary, with an oscillating multi-tool.
21. Drill out the lock-side jamb to receive the strike plate for the doorknob.