Home Improvement Skills & Specialties Carpentry & Woodworking Building Furniture

How to Build a Window Seat

Lee Wallender

Updated on 05/03/22

Reviewed by

Deane Biermeier

Window Seat — Chuck Collier / Getty Images

Project Overview

Working Time: 6 hrs
Total Time: 8 hrs

Skill Level: Intermediate
Estimated Cost: $200–$400

A window seat is that extra touch that transforms your house into a real home. With your new cozy perch, you'll enjoy reading, chatting with a friend, or basking in the sun. Top the window seat with a cushion for comfort and add fun pillows. On the functional side, this DIY window seat comes with over 6 cubic feet of built-in storage room.

Your window seat will have a flawless, professional look because of one secret: pre-built wall cabinets. Available by order or in-stock at many home centers, wall cabinets make this job largely about assembly rather than about building cabinetry from scratch. This allows you to devote more time to painting your window seat, attaching stylish cabinet pulls, and adding a seat cushion.

With a hardwood top suitable for painting in any color of your choice, this window seat will be 60 inches wide, 19-1/4 inches high, and 15 inches deep.

Equipment / Tools

Electric miter saw
Cordless drill
Drill bits and driver bits
Cordless electric nailer
Circular saw
Prybar
Tape measure
Hammer
Speed Square
Carpenter's pencil
Stud finder
Paintbrush
Sandpaper
Tack cloth

Materials

2 Wall cabinets, each 30 inches wide by 15 inches high
1 Trim board, 3-1/2-inch by 96-inch
3 Two-by-fours, each 96 inches long
1 Sheet of hardwood plywood, 3/4-inch thick by 4-foot by 8-foot
1 3/4-inch by 3/4-inch quarter-round, 96 inches long
3-inch stainless steel common nails
#10 Phillips head wood screws in four lengths: 3/4-inch, 1-inch, 2-inch, and 3-inch
Washers
Carpenter's glue
Primer
Interior-grade paint
Paintable caulk (optional)

The building block of your DIY window seat is the standard 30-inch-wide by 15-inch-high wall cabinet. Its 30-inch width means you can use one unit for narrow windows or double it up for wider windows. At 15 inches high, it will reach the same height as most chair seats when combined with its 3-1/2-inch high base. While 12 inches is not deep enough for comfortable seating, this will be remedied by pulling the cabinet forward 3 inches and covering the back section with a cantilevered plywood seat base. Be sure to purchase hardwood plywood, a type of furniture-grade plywood topped with a fine veneer such as birch.

Choose an Area for the Window Seat

You likely already have an ideal spot in mind for the window seat. Make sure that it is at least 60 inches wide and that the bottom of the window rises at least 20 inches above floor level. Also, be sure not to locate your window seat over an HVAC vent or in front of a baseboard heater.
Remove the Cabinet Doors and Shelves

Remove the cabinet doors and any shelves since this lightens the cabinet. Leave the hinges on the cabinet. Set the doors, shelves, and screws safely aside.
Remove the Baseboard and Obstructions

Gently pull away the baseboards with the prybar. Remove other wall and floor obstructions such as door trim, door stops, and floor transitions that will be unnecessary after the window seat is installed.
Build the Window Seat Base

The heart of the window seat is its two-by-four frame. Cut two two-by-fours to 60 inches long each. Using the waste materials, cut five boards to 12 inches each. Place the five 12-inch boards perpendicular between the two 60-inch boards: one at each end, one at the center (30 inches on-center), and the remaining two boards between the other boards (15 inches on-center). Nail the frame together, frequently checking for square with the Speed Square.
Attach the Window Seat Base to the Wall

Place the window seat base in front of the window so that the back of the frame touches the wall. Locate three wall studs with the stud finder. Pre-drill holes on the inside of the base frame at the location of each stud, then attach the base frame to the wall with the 3-inch screws and washers.
Attach the Wall Cabinets to the Base

Using the cordless drill and the 1-inch screws, attach the wall cabinets to the base frame. The cabinets should first be attached together, from the side, with 2-inch screws. Next, attach the paired cabinets to the frame, stepping them 9/16-inch forward to allow for flush insertion of the trim board underneath as a toe-kick.
Attach the Trim Toe-Kick

Cut the trim board to 60 inches on the miter saw. Place the trim board across the front of the base frame as a toe-kick. With the cordless electric nailer, attach the toe-kick with six to seven finish nails.
Cut the Seat to Size

With the circular saw, cut the sheet of hardwood plywood to 60 inches by 30-1/2 inches.
Attach the Seat

Rest the seat on the cabinets, with the factory-finish edge facing outward. The back should nearly touch the wall, with just a slight 1/8-inch gap. Using the cordless drill, drive 3/4-inch screws upward through the roof of the cabinets and inside the seat plywood. Make certain that the screws sink into the plywood but do not pierce the top of the plywood. Attach with eight screws.
Attach the Quarter-Round

With the miter saw, cut the quarter-round trim to 60 inches long. Run a thin bead of carpenter's glue along the front edge of the window seat. Attach the quarter-round to this edge with thin finish nails. Be careful to quickly wipe up any carpenter's glue that might squeeze out.
Sand and Paint the Window Seat

Lightly sand with fine-grit #220 sandpaper, particularly the joint between the quarter-round and the seat to bring down any minute lips or to sand off dried glue. Apply paintable caulk to any gaps between the seat and the wall if desired. Prime all surfaces, let dry for at least two hours, then apply two coats of interior-grade paint. Attach the doors again after all of the paint has dried.