How to Build a Doorway to a Room

Determine if the wall is a load-bearing wall -- this type of wall typically runs perpendicular to the floor joists. If you are not sure if the wall is load-bearing, contact a building inspector or contractor before beginning your project. Do not build the doorway yourself if the wall is load-bearing.

Determine the width and height of the doorway. Interior doorways are typically at least 36 inches wide and 78 inches high.

Locate the wall studs with a stud finder.

Measure the width of the doorway on the wall with a measuring tape, using one of the studs as a starting point. Mark both edges of the doorway with a pencil at the top and bottom of the wall. Snap a chalk line along the marks to create an outline of the doorway sides. Repeat this process on the opposite side of the wall.

Cut the drywall along the chalk lines on both sides of the wall with a reciprocating saw. Use a sledgehammer to break apart and remove the drywall between these lines.

Cut through the bottom plate of the wall frame at both edges of the wall with a reciprocating saw. Measuring from the floor, make a mark two inches higher than the finished doorway height on each exposed stud. Cut the studs at these marks with a reciprocating saw.

Remove the lower sections of the studs and the bottom frame plate with a pry bar.

Cut a section of 2-by-4-inch pressure-treated lumber to the distance between the top and bottom plate with a circular saw. This section forms the side of the doorway that does not already have a stud. Place this lumber section between the top and bottom frame plate, flush with the cut edge of the drywall.

Drill pilot holes through the stud into the top and bottom plates at 45-degree angles. Insert and tighten 4-inch wood screws through the pilot holes with an electric screwdriver to secure the stud to the plates.

Cut a section of 2-by-4-inch pressure-treated lumber to the width of the doorway with a circular saw. This section will form the top of the doorway frame. Drill pilot holes through this section into the ends of the cut studs above the doorway and at 45-degree angles into the studs that form the sides of the doorway. Insert and tighten 4-inch wood screws to secure the top of the door frame to the studs.

Measure a section of drywall to fit the section of the wall above the doorway. Cut the drywall with a utility knife or reciprocating saw. Install the drywall above the doorway by attaching it to the studs with drywall screws.

Cut drywall sections to cover the studs on the sides and top of the doorway. Install the drywall sections with drywall screws.

Cover the drywall seams and corners with drywall tape. Apply drywall compound with a putty knife to cover the tape edges and screw heads. Sand all drywall surfaces with a palm sander after the compound dries.