Q&A for How to Sew Bench Cushions

The most common types of material used to make pillows and cushions are fabrics that do not have a stretch. If you choose a material with stretch or lycra in it, the fabric can stretch out with time and look saggy.

A spray adhesive is the most effective way to glue foam. It is difficult to apply an even coating of any glue using a brush or roller due to the structure of the foam. Hot glue is not recommended, as it can melt the foam; it is also not as flexible as the foam.

First, measure the cushion. Then, do some math. Remember finding the perimeter of rectangles in school? You do just that but using the measurements you took. If you are forgetting how there are probably examples of how to find that online. You find the perimeter of each rectangle and use those measurements when cutting.

On one of the seams, instead of sewing it shut, get a zipper and attach it the the inside. Sew it down on both sides.

Start by knotting your thread, then insert it from the other side of the cushion. If the button has four holes, sew diagonally three times one way and then three times the other way until it looks good. For a button with two holes, sew back and forth until you are satisfied. Finish by going back, tying a knot using a double blanket stitch in the same spot, tighten, and your button is attached!

You should create a shaped pattern and sew with eased seams. First, draft or trace a pattern from your cushion, marking the square back and the rounded front curve, then add a 6–12 mm seam allowance. Cut the fabric pieces: one for the back (square) and one for the front (rounded), or two fronts for a full cover. Clip notches into the curved seam allowance, ensuring not to cut into the stitching, so the curve lies flat when turned. Pin the front to the back, right sides together, matching corners and the center of the curve, distributing ease along the curve. Sew at your chosen seam allowance, easing the fabric where necessary. Finally, trim and grade the seam allowance on the curve, turn it right side out, press, stuff or insert the cushion, and finish the opening with a ladder stitch or zipper.

To sew an invisible zipper, choose one slightly shorter than the cushion's opening. Press seam allowances flat. With right sides together, align the zipper tape edge with one seam allowance, teeth facing the fabric; pin or baste. Using an invisible-zip foot, sew as close to the zipper teeth as possible, keeping stitches straight. Repeat on the other side: align, baste, then sew. Close the zipper and press the seam flat so the zipper teeth are hidden in the fold. Topstitch or hand-stitch ends if needed, and finish raw edges. Tip: Practice on scrap to set needle position and tension.

To pin box corners, match the corner seams with right sides together, aligning the side and end panels so raw edges meet and the corner point is even. Pin through all layers at the corner point first, perpendicular to the edge. Then, place additional pins 1–2" (2–5 cm) apart along each seam allowance, keeping them perpendicular to the edge and pointing toward the corner to clear the presser foot. For precise box corners, consider basting or clipping a notch at the corner point before sewing.

To sew an inner corner, align the side and end panels with right sides together so that the seam lines meet at the corner. Sew the seam up to the corner point, leaving the final 6–8 mm (1/4") unstitched. Clip a small triangular notch into the seam allowance at the corner (avoid cutting the stitching), or trim the seam allowance to reduce bulk. Turn the cushion right side out and gently push the clipped corner out with a blunt tool, then press lightly and finish by closing any opening.

To create a faux two-piece pillow top, sew a decorative top panel onto a single cushion cover. First, cut the main cover (bottom/side) and a top panel piece slightly smaller than the full face, leaving an equal border. Finish the top panel's edges (hem or topstitch piping). Then, with right sides together, align and baste the top panel onto the front face, offsetting it to create a two-piece illusion (or stitch on the right side for a visible seam). Sew the main cover as one unit, insert your foam, and close it with a zipper or ladder stitch. You can optionally add a thin seam, rivet, or contrasting stitch around the panel to enhance the two-piece appearance.

Yes, you must always account for foam thickness. Measure the foam's height and add seam/turning allowance plus fabric ease so the cover fits snugly but not too tight. For a knife-edge cushion, cut the side panel length to equal the foam height, two seam allowances, and any batting or wrapping thickness. If using boxed or tufted construction, add extra depth for compression, and always test the fit with a muslin or by pinning the cover on the foam before final sewing to confirm the fit.

First, measure your foam's dimensions including the front curve height, back height, depth, and full width. Then, trace the curve onto paper, either by rolling the foam's edge or by using multiple depth measurements to create a smooth pattern. Draft your pattern pieces (front, back, and side panels) with seam allowances (6–12 mm) and notches, and create a test muslin to check the fit before cutting your main fabric. Finally, sew the fabric pieces right sides together, clip notches, trim seams, turn, fit, and secure the opening with a zipper or ladder stitch.

To add piping, first create it by encasing cord in a bias strip (cut 1.5–2 times cord diameter plus seam allowance), folding and basting close to the cord. Then, align this piping with the seam line of the cushion piece (right sides together, raw edges even), pinning it so the cord faces inward. Using a zipper or cording foot, sew close to the cord, catching the piping fold. At corners, miter the piping (fold at 45° for boxed corners) or overlap and trim for a neat join. Finally, sew the opposing cushion piece (right sides together) with the piping sandwiched between, trim the seam allowances, turn right side out, and press.

To cover a cushion with an angled corner, trace the cushion outline, including the angle, and add a seam allowance (6–12 mm). Cut your fabric pieces (front, back, and side panels) accordingly. Clip notches into the seam allowance along the angled curve or point (using V notches at sharp angles) to reduce bulk. Pin the right sides of the fabric together, matching the angled corner precisely, and pin perpendicular to the seam so pins clear the presser foot. Sew slowly, pivoting at the corner point (leaving approximately 6–8 mm unsewn before pivoting), then continue. Finally, trim and grade seam allowances at the angle, turn the cushion cover right side out, push out the corner with a blunt tool, press, and finish the opening.

To calculate the fabric needed, you should measure one cushion's front width, front depth, back width, back depth, and foam height (H). Determine the side panel length by adding the front perimeter (including curves) and back width, and the side height as H plus seam allowances and wrap. Calculate the fabric for the front and back pieces as 2 × (width × depth), and for the side pieces as (side length) × (side height). Add 10–15% for pattern matching, shrinkage, and repeats, plus extra for fabric nap. Finally, divide your total by the fabric width (e.g., 54 inches) to get linear yardage, rounding up to the nearest 0.25–0.5 yard.