How to Build a Window Seat to Hide Ductwork

Measuring and Cutting

• 1

  Measure the width of the window sill to determine the width of the window seat. Mark this measurement on the baseboard below. For this example, we are using an 18-inch window sill.

• 2

  Slide the edge of a utility knife between the wall and the back of the molding to separate the wall from the molding. Place the straight end of a small pry bar between the wall and the molding. Carefully pull the baseboard from the wall. Separate the baseboard and the molding past the markings.

• 3

  Wedge the small pry bar in the opening near the marking. Cut the baseboard and molding at the mark with a hacksaw.

• 4

  Measure and cut four 2-by-4-inch boards 18 inches long. Measure and cut four 2-by-4-inch boards 16 inches long. Measure and cut four 2-by-2-inch posts 24 inches long. Use a circular saw to cut the boards to size.

• 5

  Measure and cut a plywood sheet 18-by-20-inches for the top. Measure and cut two plywood sheets 24-by-20-inches for the sides. Measure and cut a plywood sheet 18-by-24-inches for the front. Use 1-inch-thick plywood for the coverings. Cut the plywood with a circular saw.

The Frame

• 6

  Lay out two 18-inch boards parallel with the ends flush. Set them up with their 2-inch edges on top. Create a distance of 16 inches between them. Set the 16-inch boards between the 18-inch boards. Have the 2-inch edges for the shorter boards facing the same direction as the longer boards.

• 7

  Line up the shorter boards so their ends butt against the inside edges of the longer boards. Make the ends and edges flush forming a rectangle 18-by-20-inches. Apply a bead of wood glue where the boards meet. Set a clamp at both ends so they press against the exterior of the 18-inch sides. Let the glue dry.

• 8

  Remove the clamps. Drill two 3-inch wood screws through the sides of the long boards into the ends of the short boards.

• 9

  Construct a second frame the same way as the first frame.

• 10

  Stand up a 2-by-2-inch post in each corner of one frame. Make the edges flush. Drill a wood screw through the frame into the post where they touch. You will have two adjacent screws holding the posts to the frame.

• 11

  Overturn the frame with the posts attached. Stand up the posts into the corners of the second frame. Make the edges flush. Attach the posts to the second frame as you did the first frame.

Assembly

• 12

  Lift the seat frame up over the extended ductwork. Set the frame in place underneath the window.

• 13

  Set an18-inch side of the frame against the wall between the cutout section of the baseboard. Adjust the fit of the frame by removing small sections of the baseboard with a hacksaw. Drill a wood screw through the rear boards of the frame into the wall next to each post. Drill screws every 2 ½ inches along the boards into the wall between the posts.

• 14

  Set the top sheet of plywood over the top of the frame. Make the ends flush. Hammer 2-inch wood nails through the plywood into the corners of the frame. Hammer nails every 2 ½ inches through the top into the top boards of the frame.

• 15

  Line up the side pieces of plywood against the sides of the window seat. Rest the piece on top of edge of the bottom frame. Make the edges flush. Hammer wood nails through the plywood into the corners of the frame. Hammer nails every 2 ½ inches through the piece into the front, top and back boards of the frame.

• 16

  Lay the front piece of plywood flat on the floor. Set a metal grate face up on the center of the sheet so the sides of the grate match with the corresponding sides of the plywood. Trace the outline of the back of the grate on the plywood. The back should be smaller than the face of the grate.

• 17

  Remove the grate. Use a jigsaw to cut out the trace lines and discard the cutout. Mount the grate into the opening created. The front facing should rest against the plywood behind it. Drill holes through the plywood using the holes in the grate corners as a guide. Place 1 ½-inch bolts through the holes. Screw corresponding bolts onto the back of the bolts to attach the grate to the plywood.

• 18

  Mount the front plywood sheet to the front of the frame the same way you mounted the two side pieces.

Finishing

• 19

  Fill wood putty over the nail and screw heads.

• 20

  Sand the entire window seat with medium-grade sandpaper.

• 21

  Paint or varnish the window seat to taste using a 2-inch brush for an even coat throughout. Let the finish dry overnight.