A window seat is a special part of a home. It is a cosy spot people can use for reading books or simply enjoying the view. Windows in a niche often have a wooden seat that doubles as storage underneath. It is both a practical feature and an aesthetic element of a room. If you want to make your window seat more comfortable, add a box cushion and cover it. Or if the seat has a cushion, replace the cover to give the seat a different look.
Measure your window seat and use the dimensions to buy the material. Buy more fabric than you need because box cushions usually have big seams. For example, add at least 2 to 3 inches to every edge of the cushion’s six sides.
Remove the old cover fabric to strip the cushion to its foam core. If it has a zipper, simply slide the cover off. If it doesn't, cut the fabric with a utility knife or scissors, being careful not to damage the foam inside.
Spray heavy-duty adhesive all over the surface of the foam, including the sides. Press a piece of soft batting in the shape of the cushion to the top surface of the foam. Fold the excess batting over the sides of the foam rectangle. Apply a piece of batting to the other side of the foam in the same manner. This way, your window seat cushion will be soft and cosy.
Use sharp and large scissors to cut six pieces of fabric for the six sides of the box cushion. Make every piece at least 2 inches bigger than the final, needed dimension.
Sew together the six pieces of fabric so they form the final shape of the box cushion. Use a sewing machine and make sure to choose a strong thread in the colour of the fabric. Start with the small sides, to make a ring of four narrow pieces. Then attach the top and the bottom of the cushion as well. Leave one edge of the box cushion cover open for now. That will be the place for the zipper, which will enable you to take off and wash the cover. You can leave open one edge of the bottom of the cover. Or you can sew all edges first and then make a new cut through the middle of one longer narrow side. Remember that you have to sew inside out, so be sure the fabric is on its back side while you work.
Add a zipper to one side of the cushion cover, following the instructions for sewing from the previous step. Again, sew the zipper in the back so the stitching is invisible. Choose a strong metal or plastic zipper and be sure it is long enough so you can easily take out the foam insert.
Turn the fabric on its right side and put the cover on the rectangle foam insert. Check that the cover fits perfectly on the foam. If it doesn’t, trim the foam with an electric knife so it fits inside the cover.
Buy either more of the same material or a completely contrasting fabric for the soft throw-pillows on the window seat cushion. Matching fabrics look harmonious; contrasting fabrics look interesting and stylish. Many window cushion seats have inside-out stitching, so consider this idea.