Things You'll Need
2-inch foam sheet
Hand sewing needle
An Adirondack chair, which is made with flat wooden slats, can be more comfortable to sit on if it has a chair cushion. The cushion covers the seat and the back of the Adirondack chair, with ties to secure it at the point where the seat and back meet and another set of ties near the top of the cushion. When making a cushion for an Adirondack chair, be sure to select a fabric that is made for outdoor use. Although any canvas-type material will work, it will not hold up as well as a fabric specially made to stand up to the elements. One such fabric is the Sunbrella brand. This type of foam has an open-cell construction and dries much more quickly than standard foam.
Cut one 20-by-30-inch piece of foam for the back and one 20-by-18-inch piece of foam for the seat.
Cut two 23-by-44-inch pieces of fabric. With the right sides together and using a 1/2-inch seam, use a sewing machine and standard-weight thread to sew together the two 44-inch sides and one 23-inch side. Sew again for durability. Turn the right side out. You now have pillowcase shape.
Insert both pieces of foam into the cushion case. Fold over raw edges on the open end of the case and use button thread (a heavy, durable thread) to hand sew the case closed.
Pin the fabric to create an indented line going across the case at the point where the two pieces of foam for the seat and the back meet. This will separate the two pieces of foam and allow the cushion to bend. Using button thread and a running stitch, hand sew a line from one side of the cushion to the other.
To make the ties, cut four 2-by-14-inch strips of fabric. For each piece, lay down the strips with wrong side facing up. Turn up each long edge 1/2 inch so that they meet in the middle. Press. Fold the entire strip in half lengthwise. Press again. Use a sewing machine to sew a straight stitch along both long edges, and a zigzag stitch to finish short, raw edges.
Using button thread, securely hand sew one end of two ties to the sides of the cushion at the point where the seat bends. Sew the remaining two ties to the sides of the cushion 6 inches from the top.