T-cushions are commonly found on larger armchairs. The cushion can be a seat or seat back. The majority of the cushion is a square shape except where the cushion wraps around the arms of the chair. Two projections curve around the front or top of a chair arm to create a T-shape in the cushion. Making a T-cushion is easy with the right tools. Covering the cushion is also well within the reach of most homeowners.
Take a large piece of white craft paper and place it on the seat base of an armchair. Trace along the paper where the cushion will fit against the seat back, the arms, the front of the arms and along the front edge of the seat base. Cut out the outline using scissors.
Place the pattern over 4-inch foam and trace the outline onto the foam using a marker. Cut the foam at 2 inches larger than the outline on all sides using an electric carving knife. This will allow you to test-fit the cushion and adjust the fit since the cushion is thicker and will fit the chair differently than the thin paper pattern.
Position the cushion on the chair seat base and trim the foam to the correct dimensions for the best fit. The cushion should fit snug but not bulge up in the middle. The edges should match the edges of the chair.
Place the new cushion over a new piece of paper and trace a new outline, add 1/2-inch seam allowance on all sides. This will be the pattern for the cover.
Launder and iron the decorator upholstery fabric you are using to make a cover for the cushion. Fold the fabric in half and pin the pattern to the fabric. Cut the top cover pieces. Measure the length of each side and add 1-inch for seams. The height should be 5-inches. Cut each side allowing for a seam at each corner. Cut two pieces for the back side that is closest to the seat back.
Sew a zipper into the two back pieces that is 2-inches shorter than the total length of the back side. Trim the top and bottom of the finished zippered section to 5-inches in height. Place the back and one side piece, face sides together and sew the corner seam using a 1/2-inch seam allowance. Repeat for the second side.
Place one side piece and the back side of the T-shape, face sides together and sew a corner seam using a 1/2-inch seam allowance. Repeat for the other side. Place the back side of the T-shape, face sides together with the side of the T-shape and sew a corner seam using a 1/2-inch seam allowance. Repeat for the other side. Place the side of the T-shape and the front of the cushion, face sides together and sew a corner seam using a 1/2-inch seam allowance. Repeat for the other side. This will create a large loop of fabric.
Position the large loop of fabric face sides together with the top cover. Align the corner seams with the corners of the top cover and pin with a 1/2-inch seam allowance. Pin all the way around the cover top. Sew the 1/2-inch seam around the cover top. Repeat for the bottom cover. Clip the corners and turn the cover right side out using the zippered opening.
Fold the T-shaped cushion in half so that the T-ends are together. Insert the cushion into the zippered opening and press it to the front of the cover. Unfold the cushion and tuck each corner into place with your fingers. Smooth the foam and adjust the cover to fit snuggly over the cushion. Tuck the back of the cushion inside the cover while adjusting the corners and zipper the cover closed.
Cording can be added to the cushion edges by cutting a fabric strip on the bias and covering cording with a stitch tight to the cord. Insert the cord between the top cover and side edge and between the bottom cover and side edge during the sewing process. Always start cording in the middle of the back side and overlap the fabric by trimming the cord back behind the overlap.