How to Frame a Window Bench Seat

Measure the length of the enclosed cove space you wish to place the window seat on with a tape measure. Mark this measured length onto a piece of 2-by-4-inch planking with a pencil. Use a straightedge to draw a line across the plank at the marked location, and then cut the plank with a circular saw.

Measure the desired height of your window seat. Create studs for the front frame to serve as support for the seat structure as well as locations to attach paneling to for the seat body. Divide the measured length of your seat by 16 inches, and cut a stud to the desired height minus 3 inches, to account for the heights of the top and bottom 2-by-4 planks. Nail the studs to the base plank every 16 inches, making sure to place a stud at each plank end to serve as edges to the frame.

Choose a depth for your window seat and mark a line onto the floor the desired distance from the window front. Secure the bottom plank to the floor of the room at the marked distance by nailing it into place if the subfloor is of wood, or by using a power actuated nailer with concrete floors.

Cut two more 2-by-4s to the length of the seat. Attach one of the boards along the top of the nailed frame, and the second board onto the wall beneath the window at the desired seat height. Use a carpenter’s level placed across the two boards to position the window board so that it’s level before nailing it into place. Check the wall beneath the window for the location of wall studs with a stud finder, and nail the board directly into the studs to secure it fully.

Measure the distance between the front and rear top frame boards of the window seat. Cut 2-by-4 planks to fit the space, and then nail the planks between the two boards, placing nails through the sideboards into the sidewalls of the window alcove and through the front frame into the sideboards as well. Place an additional piece of plank in the center of the structure between the front and rear boards for additional support. This will create a rectangular frame for the top of your window seat, and give you a complete frame for the seat that you can cover with the wood of your choice.