Framing the window seat

• 1). Take the measurements needed to cut the 2x4 lumber to form the frame for your window seat. You will be making a rectangular box with studs running left to right (the width of the seat); from front to back (the depth of the seat), and from the floor to the desired height of the seat.
  
  Note: You will be covering the stud frame with 3/4-inch plywood, so adjust the final measurements to allow for the thickness of the plywood. For example, if you wanted the finished window seat to be 45 inches wide, you would cut the longest studs to 43-1/2 inches, allowing for the thickness of two 3/4-inch plywood side walls.
  
  
• 2). Cut your 2x4 studs to the measurements. Lay out the framing members on the floor and screw them together, using 3-inch drywall screws.
  
  
• 3). Attach the frame to the wall under the window: Find the wall studs under the window by lightly knocking on the wall and listening for the solid sound that indicates a stud lies behind the wall. Drive 3-inch drywall screws through the framing stud, the drywall, and into the stud behind the drywall surface. Secure the frame to the floor by driving screws through the framing members into the floor.
  
  
• 4). Measure the frame and cut the plywood to cover the sides of the window seat.
  (You will be covering the top with a hinged piece, so do not cut a piece for the top yet.)
  If you want a floor in the box, cut a piece of plywood to fit inside the frame and secure it to the floor using drywall screws of appropriate length.
  Secure the plywood sides to the three exposed sides of the frame using 1-1/4- inch drywall screws every 9 inches or so.
  
  

Creating the window-seat top

• 1). Measure and cut a piece of plywood for the top of your window seat. Cut it so that the edges overlap the sides by 1/4-1/2 inch, according to how you want the finished seat to look.
  
  
• 2). Fasten the style of hinge you prefer to the rear edge of the plywood top. The width of the top should determine the number of hinges needed: Two heavy-duty hinges usually are sufficient for anything less than 4 feet. On longer tops, or if a particular design effect is desired, you may wish to use a continuous hinge, otherwise known as a piano hinge.
  
  
• 3). Position the top carefully on the framed and paneled window seat. Drive the hinge screws into the framing or plywood inside the seat at the rear of the window seat. Cut pieces of 1-by lumber to the desired width (rip them to width using a table saw). Attach these pieces to all unfinished plywood edges of your window seat, i.e., the top and the sides.
  
  
• 4). Cover the top of your window seat with fabric or upholstery. Keep in mind that you will be opening and closing the top, so choose the fabric and attachment methods accordingly.
  Paint or stain the window seat using single or multiple trim colors to suit your taste.