I have had this chair for many years. It is well made and still in great shape, clean but stained. As you can see the upholstery fabric probably dates back to the 60's with it's orange and brown stripes.
I use it as my sewing chair and decided to update it with chenille slip covers.
My vintage chenille spread had a design I wanted to incorporate into it so I roughly cut a large enough rectangle of fabric to fold over the seat back.
With the right side of the fabric against the back of the chair, I pinned the sides of the chenille together leaving about 1/2 inch of room between the chair and the pins. Pin from the curve of the top, around the sides and continue straight down at the bottom, not following the bottom curve of the chair or you won't be able to get the cover off and on the chair back.
I measured the chair back from top to bottom and then added 1 3/4 inches. This is the measurement I used to figure the length of the cover.
Laying the cover on my table I marked my measurement on the slip cover and cut the bottom evenly across.
I resewed the seam allowance and turned it right side out.
I sewed the side seams in a 1/4 inch seam and made a small hem on the bottom edge.
I sewed double gathering lines around the top edge of the ruffle, the first one 1/4 inch from the edge and the second gathering line 1/8 inch away from the first.
Pulling both threads together I slightly gathered the ruffle to match up to the bottom of the cover and pinned them right sides together.
I sewed them together following the second line of stitching.
For the seat cover I laid the chenille on the seat exactly where I wanted the pattern of the chenille to sit and very carefully cut around the chenille using the bottom edge of the seat as my cutting line.
Using the chenille as a pattern, I cut the batting and lining to match. I pinned all three layers together with the chenille and lining right sides out and the batting in between. I tacked all three layers together on my machine at equal distances apart. If you don't have a stationary tacking stitch on your machine, you could use a zig zag stitch which is what I did. The fabric layers are so thick they didn't move as I sewed several times in one spot. You could also tack them together by hand.
Then I zig zag stitched the layers together all around the outside edge.
I sewed the sides seams together, leaving one seam open because the ruffle will have to be left open at the back to fit around the metal piece that holds the seat and back together.
I hemmed the sides and bottom of the ruffle and then sewed the gathering lines across the top the same as the seat back ruffle only this time because of the length of the ruffle, I broke the gathering lines up into four parts to make it easier to gather the fabric without breaking the gathering threads as I pulled on them. There is nothing more frustrating than to have your thread break when you are gathering a large expanse of fabric up so I always break up large areas of gathering thread.
Ties: I would have preferred wider ties but I only had a limited amount of the co-ordinating fabric. These are my measurements but you can change them if desired.
Cut two pieces of fabric, 2 1/2 inches wide by 21 inches long. Fold in half and stitch across the bottom and down the sides in a 1/4 inch seam, leaving the last end open for turning.
Turn right side out and press. Pin them to the center of the back seat cover, leaving one inch in between the ties. Stitch across the ends of the ties to secure them.
With right sides together, and starting at the middle of the back of the seat cover, gather the ruffle to fit the cover. Sew the ruffle to the cover.