A standard box cushion has a flat top, flat bottom and four sides that are created by sewing a separate piece of fabric to connect the top and bottom. It can be any shape: round, square, rectangular or cut to a particular shape, such as a bay window seat, for example. The sides, called the “boxing,” range in depth from 1 inch to 10 or more inches. The edges of the cushion are not soft or graded; they are as close to a 90-degree angle as possible. The filler of the cushion is firm and enhances the structure of the cushion, the most common filler for large box cushions being Dacron or terylene-wrapped sheet foam.
Piped Box Cushion
Piping is often sewn into the seams of the box cushion to create a "piped box" cover. Piping is a fabric trim that is frequently made of the same fabric as the cushion cover or is made of contrast fabric. Piping adds definition to the plain box cushion, which is the most common cushion on upholstered sofas and chairs. A zipper set into the section of the boxing that rests against the back of the chair allows the cover to be removed for cleaning.
Mock Box Cushion
A simpler version of the standard box cushion is the "mock box." Rather than a top, bottom and boxing strip, this version has two flat pieces sewn as a square, and the corners are miter-sewn to create depth, which causes the perimeter seam to fall halfway down the sides, front and back of the cushion. Piping is sometimes set into this seam. This box cushion is straightforward to make and is often seen in slipcover pieces of country decor style. Velcro or a zipper set into the seam along the back of the cushion allows for cover removal.
Bull-nose or Waterfall Box Cushion
Bull-nose or waterfall box cushions are a combination of a mock and a standard box. One piece of fabric wraps from the back of the top of the cover to the front, down the depth of the cushion to the seat and along the underside to the back. The cushion depth at the back and sides is accommodated with a boxing strip. This cushion is most often used in outdoor applications because rain will roll off the front as in a waterfall, hence the name.
Gathered Box Cushion
A decorative version of the standard box is that of a gathered, or "shirred box." The boxing is gathered tightly before being sewn into place. In addition, this cushion often has a thick fringe set into the seam connecting the top and boxing and is a highly decorative cushion, usually found in formal settings only.