How to Make a Rough Opening for a Pre-Hung Door

Inspect the wall area on both sides to look for potential obstacles. For example, if an electrical outlet is located near the area, you will likely find wiring when you cut out the wall that needs to be moved.

Determine if the wall is a load-bearing wall. If it is, you'll need to install a header above the door to help support the load. To accommodate the header, you'll need to remove more of the wall at the top of the door.

Read the information provided with the pre-hung door you purchased. The information should indicate how large of a rough opening is necessary to accommodate the door. If this information isn't provided, cut out the area of the door and jamb plus 3 inches on either side and on the top for framing.

Locate the studs in the area where you want to place the door. Position the rough opening so you are able to have studs on either side of the opening. Draw the dimensions of the rough opening on the wall as a guide.

Cut the drywall with a utility knife along your outline for the rough opening. Pull off the drywall, using a pry bar to remove it from the studs if necessary. Cut the lath on a plaster wall using a reciprocating saw if you have a plaster covering. Pry down the plaster and lath to open the area.

Support the ceiling with posts if you are cutting into a load-bearing wall. Do this before you begin cutting the studs.

Cut the studs from the rough opening area. Use a reciprocating saw to cut down the studs. You are now ready to frame the rough opening before installing the pre-hung door.