Outdoor Seat Cushions – How To Make Your Very Own

Outdoor Seat Cushions – DIY

Outdoor seat cushions offer significant comfort to a bench and seating area, and they also are an ideal way to add color splash and inspiring design elements to the area. As we all tend to flock outdoors in the warmer season months, this DIY feature will detail how you can create your very own outdoor seat cushions easily and inexpensively, and enjoy their inherent comfort as you relax and unwind.

Outdoor seat cushions
Outdoor seat cushions

Supplies that are required for this DIY outdoor seat cushions project include:

  • 12 ounce bull denim or outdoor Sunforger fabric or 600Denier PVC backed poly 
  • Note: if you are using Bull Denim you will need to apply a waterproofing solution to the fabric material, such as Star Brite waterproofing spray
  • outdoor cushion filling such as Nu-Foam – select one with 4″ depth
  • standard sewing machine
  • a zipper the width of your cushion (you will need 1 per cushion)
  • fabric scissors
  • measuring tape
  • sewing pins
  • sew-in zipper (which should be length of one of the cushion ends/ sides)
  • electric knife, hand saw or jig saw for cutting foam inserts

Step-by-step Instructions:

1). First, with your measuring tape, accurately measure the depth and the width of the intended bench or seating surface to properly determine how big your outdoor seat cushions are going to be. Also, and in the event that you will be making the vertical back cushions, you may also wish to measure the height from 4 inches to the top (as the outdoor seat cushions will be using a 4” tall foam insert).

Measuring your outdoor seat cushions fabric
Measuring your outdoor seat cushions fabric

2). As we will be sewing these seat cushions with a ½” seam all the way around each of them, ensure that after measuring the dimensions that you add an additional inch to account for the ½” seam allowance.

Sewing a seam allowance
Sewing a seam allowance

3). Determining the dimensional height of the cushion, and again as we will be utilizing a 4” foam insert, simply add 1 inch to the 4 inch height to accommodate for the ½” seam.

4). Now it is time to accurately cut out the bottom and top fabric panels of the bull denim or Sunforger canvas with our fabric scissors, and which we will sew together with the cushion height “runner piece” – which will be 5 inches tall. 

Cutting the outdoor seat cushion fabric
Cutting the outdoor seat cushion fabric

5). Use your fabric scissors to round out the edges of the corner on the 3 larger panels of the fabric.

6). To connect your long side panel strip and make one big continuous loop around the edge of your cushion, fold the panel in half (with the right sides facing each other), and sew 1/2″ from the edge to connect the ends.

7). Line up the edges of your side panel loop of fabric with the edge of the top panel and with the right sides together. Now, pin the edge in place.

Pinning your outdoor seat cushions fabric
Pinning your outdoor seat cushions fabric

8). Often times, adding V-shaped notches around the corners of the fabric make the sewing easier.

V shaped notches in fabric make sewing easier
V shaped notches in fabric make sewing easier

9). We are now fully ready to begin sewing the panels together with the ½” seam.

10). In the same way that we pinned the top panel, we will now pin the bottom panel to the side panels, and again make the v-shaped notches on all of the corners.

11). Prior to sewing all the way around the bottom panel, we will need to sew in the zipper. The zipper will allow you to insert the 4” high foam filler, and which is the actual cushion. The zipper also allows for removal of the filler cushion down the road, if you ever wanted to replace it.

Sewing a zipper into your seat cushions

12). Position the zipper face down onto the right side of the fabric, and at one of the bottom panel ends.

13). Pin the zipper in place such that the zipper will be installed ½ inch from the edge.

14). Hopefully, your sewing machine has a zipper foot, as this will ensure an easier time of sewing in the zipper precisely and effectively.

15). Now repeat this same process of pinning and then sewing the other side of the zipper. After this, you should have a perfectly sewn in zipper in place. Test that the zipper opens and closes with ease.

16). Now you can finish sewing all the way around the rest of the bottom panel.

17). Turn the outdoor seat cushion cover right side (correct side) out, and now we will move on to cutting the cushion filler.

18). Using a ruler and a marker, measure the exact width of your cushion filler from the dimensions that you already determined at the beginning. Note – it is okay to use multiple cushion fillers if you cannot source one piece large enough to fill your seat cushion. Additionally, it is recommended that the insert be slightly bigger than the actual dimensions to ensure a snug fit and full outdoor seat cushion.

Cutting your foam cushion insert to spec
Cutting your foam cushion insert to spec

19). After marking the filler insert with the marker, you can utilize the hand saw, the electric knife or the jig saw. All are effective, but the jig saw seems to create the sharpest edges and is the easiest to stay in proper alignment and ensure accuracy of the cut. If you do not have access to the electric knife or the jig saw, then the hand saw will work well . . . just ensure your hand saw is one that has a higher count of teeth-per-inch (a keyhole blade works great as well). Rule of thumb: “the more TPI, the smoother the cut.”

20). After cutting your cushion filler insert, you can now fold it up and insert it into the cushion cover through your new zipper insert.

21). Final note and reminder: if you are using the Sunforger canvas or the bull denim, ensure that you use your water-proofing spray to cover the cushion in its entirety as this will ensure no mildew forms on your fabric material once placed outside in the elements, and the rain!

Now, after completing your DIY outdoor seat cushion, you may want to continue on and craft others, or simply use these detailed instructional steps to create smaller outdoor pillows to accent the larger seat cushions and seat backs. Really, the only things that will change are perhaps the fabric type, the amount of fabric, and the size of the pillow insert filler (you would want to use pillow stuffing in lieu of the cushion insert). And now you have an enjoyable and comfortable outdoor seat cushion made especially for you, and by you!