How to Build a Window Seat

Attach a top support and lower support to the inside of each side with glue and 1-1/4-inch drywall screws. Make sure the upper supports are flush with the front and top of the sides. Make sure the lower support is flush with the front and bottom of the sides.

Apply glue on the back edges of the side pieces. Put the back in place, making its edges flush with the outside, top, and bottom of the sides, and then secure it with 1-1/4-inch drywall screws. Attach the front to the sides in the same way. Check for square.

Cut a piece of 2x2 or 2x4 to 46-1/2 inches long and then rip it to 1-1/4 inches wide to make the cross support (H). Attach the cross support with glue and clamps into the upper support notches and with glue and screws through the back.

Center the remaining top support and bottom support across the inside of the bench. Make sure they are square to the front and back and flush with the top. Then attach them with two 1-1/4-inch screws through the front and two through the back.

The optional bottom increases the versatility of the bench by turning it into a freestanding chest. The bottom rests atop the three lower supports (G) plus four cleats attached inside of the front and back. The bottom shown here is a single piece of 1/2-inch plywood. If you don't have a piece of plywood, don't buy a full sheet just for the bottom. Instead, use 1/2-inch- or 3/4-inch-thick boards of any width you have, ripping one of the boards so the combined width spans from front to back.

To make the cleats (O), rip a 48-inch length of 3/4-inch plywood to 3-1/2 inches wide for the back cleats. Then tilt the saw blade 10 degrees and rip another 48-inch length for the front cleats. Crosscut the four 23-5/8-inch pieces.

Attach the cleats to the front and back between the lower side supports and the center support using glue and 1-1/4-inch drywall screws. Install the two beveled cleats against the front with the beveled edge even with the tops of the support pieces.

Cut the 1/2-inch-plywood bottom (N) to 17-3/4 by 46-1/2 inches. Put glue on the tops of the cleats and lower supports. Install the bottom and secure it with a few 1-1/4-inch drywall screws.

You might wish that you had a third hand to hold the sides of the window bench on edge while you screw them together. The job will be easier if you make a simple cabinet stand from 3/4-inch plywood. Make a 6x12-inch base and two sides that are 4 inches tall by 12 inches long. Using two scraps of 3/4-inch plywood as a 1-1/2-inch spacer, screw through the bottom into the sides with six 1-1/4-inch drywall screws. Use the stand to hold up each side while you screw the back, and then the front, into the sides.