How to Make a Double Vanity Cabinet

Lay out two 72-inch 2-by-4s, parallel to each other and resting on their long, thin sides. Position them about three feet apart and have an assistant hold them in place. These are the long frame boards.

Put two 36-inch 2-by-4s in between the long frame boards, against each end so that the four boards form a rectangular frame measuring 39 by 72 inches. Drill two holes through each long board and into each end of the 36-inch boards, which are the vertical support boards. Secure the boards together with 3-inch wood screws. Attach another vertical support board directly in the middle of the frame in the same manner.

Repeat this process to create a second rectangular frame.

Stand the two rectangular frames upright on their long edges, about two feet apart, with the help of an assistant. Position a 24-inch 2-by-4 in between the two frames at each corner, with the large surfaces facing up and down. Drill two holes through the outside of the long frame boards and into each end of each of the 24-inch boards, which are the horizontal support boards. Attach the boards together with 5-inch wood screws to create a rectangular box that is 31-by-39-by-72 inches. Repeat to install horizontal support boards in the middle of each long board as well.

Set a 3/4-by-31-by-40 1/2-inch plywood board evenly against each end of the rectangular box frame. Attach the plywood to the frame by drilling 3-inch wood screws through the interior of the frame and out into the plywood, spacing the screws every six inches along the frame.

Set a 3/4-by-31-by-73 1/2-inch plywood board on top of the frame and attach it to the frame in the same manner as the other plywood boards. Flip the frame upside down and attach an identical board to the bottom. Flip the frame back right side up.

Hold two 3/4-by-36 1/2-by-40 1/2-inch plywood boards against the front of the double vanity, evenly spaced, with a slight gap between them. These boards are the doors. Slide two side-mount cabinet hinges between the door and the outside side boards or the vertical frame boards and mark the attachment screw holes of the cabinet hinges. Attach the cabinet hinges, using 3/4-inch wood screws.

Set a magnetic 2-part latch between each door and the central vertical support board. Drill out the screw holes and attach the latch to both doors and the central post using 3/4-inch wood screws.,

Set the vanity against the wall and floor and position one of the sinks upside down above it. Mark the outline of the sink against the vanity. Decrease the size of the marking to reflect the ideal size of the sink opening so that the sink can rest within it and be supported, making the marking slightly smaller than necessary to allow for error.

Drill a small hole in the center of what will be the sink opening. Use the drywall saw to begin cutting it out. Use the hand saw once the groove is large enough. Cut out the area for the sink and keep adjusting the opening until the sink fits completely and snugly within the opening. Lift up the sink and spread a bead of caulking around the sink where it meets the wood. Lower the sink into place. Repeat with the other sink.