Prehung Interior Door Installation Print
Overall Skill Level: Intermediate

Installation instructions for prehung interior doors.
Prehung Interior Door Installation
  1. Check opening dimensions
    Check your rough opening dimensions. The rough opening height should equal the door height plus 2 ½". Standard door height is 80". The rough opening width should equal the door width plus 2" (Figure 1)
  2. Place door into the opening
    Position the door unit in the rough opening; center the unit so that you have equal spacing between the unit and the wall on each side.
  3. Install shims at the hinges
    Place shims between the door unit and wall at each hinge location.
  4. Securing the unit
    Make sure the door unit is flush with the edge of the sheet rock. Pre-drill a hole through the door stop in the location of the top hinge shim. Use one 2 ½" finishing nail to hold the door in place. (Figure 2)
  5. Check for square and plumb
    Place a 6' level along the hinge side jamb to make sure the jamb is square. Adjust the middle and lower shims until the bubble on the level is exactly in the center (Figure 2). After the jamb is square, check for plumb on the jamb. Rotate the level so it is sitting flat along the jamb (Figure 3).
  6. Tack frame
    Once the door jamb is square and plumb, pre-drill a hole through the stop in the location on the middle and bottom hinges. Use 2 ½" finishing nails to tack the frame in place (Figure 4).
  7. Shim the strike side of the door
    Shim the strike side of the door unit placing shims at the top, center, and bottom. Plumb and square the strike side of the door unit and use 2 ½" finishing nails to tack the frame into place.
  8. Verify measurements
    Make sure the distance between the hinge jamb and strike jamb is the same at the top, center, and bottom.
  9. Shim the head jamb
    Place shims in two locations across the top of the door unit, between the head jamb and wall (Figure 5). Adjust the shims until there is an even margin between the door and the frame across the top of the door.
  10. Fasten the head jamb
    Fasten the head jamb. Pre-drill through the door stop in the location of each of the two shims (Figure 6). Nail the head into place using 2 ½" finishing nails.
  11. Verify measurements and adjust shims
    Close the door and check to make sure that you have equal spacing between the door and frame at the top and along both sides. If not, adjust shims until the spacing is equal.
  12. Secure the unit with finishing nails
    Once the initial finishing nails are in place on the jambs, a second set of nails will be needed to help secure the frame. To do this, first begin by opening the door and placing a second nail through the narrower side of the jamb for each of the shim locations (Figure 7). This process should then be repeated on the other side of the door. When all the finishing nails have been installed, use a nail set to sink the heads of the finishing nails.
  13. Replace center screws on the hinges
    Once the second set of nails are in place, the center hinge screw should be removed from the top hinge on the frame (not the door side of the hinge) and replaced with a 2 ½" screw. Replace this center screw on all three hinges (Figure 8).
  14. Apply casing
  15. Finish the door unit
    A. Before finishing, a light final sanding is recommended over all surfaces of the door. Remove sanding residue before applying sealer or finish.
    B. Stain, paint, or clear coat following the finishing manufacturer's recommendations.
    C. To prevent delamination and warpage, all six sides of the door must be sealed. Door may not be cut or altered, or warranty is void.
Products, materials, techniques, tools, building codes and local regulations are subject to change; therefore, Midwest Manufacturing assumes no liability for omissions, errors or the outcome of any project. The reader must always exercise reasonable caution, follow current codes and regulations that may apply, and is urged to consult with a licensed professional before beginning any project.