A window seat made of a shelf-style bench outfitted with an upholstered cushion allows for open storage under the seat. This option, which you can make yourself or hire out, is great in utilitarian spaces such as mudrooms, entryways, or even a laundry area. Fasten the underside of the shelf to 24 cleats screwed to wall studs along the back and side walls. For added strength, install vertical supports, which can also act as cubby dividers.
An enclosed window seat can be made by adding wood paneling to the front and any exposed sides of a shelf-style seat (shown on the banquette at right) or by cladding it with drywall to create a seamless surface with the surrounding walls. Another option is to build a six-sided box set on 24 framing that's screwed to the floor. By hinging the top, the seat doubles as a storage bin.
Modular units with doors or drawers offer a pre-made base. Choose from thrifty stock cabinets sold at big-box stores, such as The Home Depot and IKEA, or made-to-order units from a local mill shop or a custom-cabinet company. Though pricey, custom lets you maximize every inch of storage beneath the seat while unifying the built-in with the rest of the room, from door style to trim to finish. Cabinets typically rest on 24 framing, but some stock and semi-custom models come with legs or a pedestal with an integral toekick.
Pro Advice: "In a kitchen or a family room, cover the window-seat cushion with outdoor fabric. It won't fade from the sun coming in and can handle people putting their feet up." —Arthur McLaughlin, Interior Designer, Arthur McLaughlin & Associates