How to Build a DIY Window Seat

Woman looking at her tablet while lying on a window seat

When it comes to return on effort, few DIY home projects come close to the beloved window seat.

Easily tackled in a single Saturday, the self-built custom window seat takes a home’s most awkward cranny and transforms it into a charming focal point.

What Exactly Is a Window Seat?

A window seat is a bench-style seat that fills up an alcove or recessed window space in a home. It’s typically designed so that the seat is flush with the walls on either side of it. Window seats can be used to reclaim and make better use of otherwise strange or awkward recessed spaces in your home, offering both a pleasant perch and sleek storage below the seat.

Building A DIY Window Seat

Designing and building your own window seat is a relatively simple and straightforward project. Follow our instructions to build your own DIY window seat.

DIY Window Seat Materials:

  • Prefabricated kitchen cabinets (chosen to fit the dimensions and desired look of the space)
  • 2" x 4" boards
  • ¾" plywood (for front panels to close gaps between the cabinet and the walls)
    • ¾" plywood or some combination of wider boards (e.g. 1" x 8", 1" x 10", 1" x 12") for the seat
  • Baseboard trim, chosen to match the rest of the room
  • Carpentry nails
  • Finishing nails
  • Hammer
  • Tape measure
  • Pencil
  • Crowbar
  • Wood filler and sandpaper (for finishing)
  • Primer, paint and stain as needed (used to achieve the desired aesthetic)

Measuring Your Space

Your design will be driven by the dimensions of the space, so the first and most crucial step is to take accurate measurements of the alcove or recess where you want to install the window seat. You should remove any baseboards and trim falling within your project footprint before measuring.

Measure the length and width of the section of floor that the window seat will occupy. Next, measure the distance between the floor and the bottom of the windowsill. This will give you a good idea of the space you are working with and will help inform your choice of cabinets.

Selecting and Installing Your Cabinets

When choosing your cabinets, the key criteria to keep in mind are sturdiness and size. Of course, style is important too, but you can always dress up neutral cabinets any way you like. You can’t make flimsy cabinets sturdier or shrink cabinets that exceed the allotted space.

The cabinets you select ought to be strong enough to support the weight of an adult. That said, you can reinforce the seat by adding 2" x 4" supports that are flush with the top of the cabinet. Don’t worry if you can’t find a cabinet or set of cabinets that perfectly fill your space. You can center the cabinets and then fill the gaps with custom-cut, painted plywood.

To install the window seat cabinet(s):

  1. Begin by creating a base using 2" x 4" boards. Cut two lengths of 2" x 4" that conform to the distance between the walls of the window alcove. Nail one of these to the base of the wall beneath the window and nail the other so that it’s flush with the two walls on either side of the alcove.
  2. Next, cut four lengths of 2" x 4" to act as perpendicular cross-supports. Nail two of these supports into place such that each will sit directly beneath one edge of your chosen cabinet (e.g. if your space is 36" wide and your cabinet is 24" wide, the supports should be placed at 6" and 30" from the left-hand wall, respectively). Then, nail the other two supports in place at regular intervals between the first two supports (using our prior example, the second set of supports would be placed at 14" and 22" from the left-hand wall).
  3. Cut four lengths of 2" x 4" to act as corner supports for your seat. They should sit atop the 2" x 4" base you’ve built, rising just to the height of the top of the cabinet. Nail these corner supports into place.
  4. Cut four 2" x 4" braces equal in length to the height of the cabinet plus the height of the 2" x 4" base. You will use these to secure the cabinet to the base by screwing the braces to both the lateral base supports and the corners of the cabinet. Screw these braces into place, stabilizing the cabinet as you do so.
  5. Cut plywood to size to span any gaps between the cabinet and the alcove walls, then nail these panels into place.

Measuring the Seat

Now your structure is in place and you are ready to install the seat. The seat should cover the full area of the window seat’s footprint. Some homeowners prefer a flush design, but the seat can also be sized to have a small amount of overhang extending in the front. You don’t want to create a knee-bonking hazard, but a half-inch of overhang or so is great if that’s the look you’re going for.

Cut a piece of plywood or an appropriate assortment of board wood slats (painted or stained to suit your design) and nail them into place to form the seat.

Trim, sand, finish and touch up as desired.

Personal Touches

You built a window seat, now it’s time to show it off!

Consider completing the space with a custom paint job, plush pillows, a classy runner or any other personal, decorative twists. Get creative, and don’t be afraid to change it up over time!

Let Glass Doctor Fix Your Panes

Hoping to replace the windows around your window seat? Curious about installing curtains or window film in your space? At Glass Doctor®, we pride ourselves on fixing your panes, big or small. Contact your local Glass Doctor or schedule an appointment online to begin your next window project.