NOTE: 1/2" seam allowance
Measurements come from existing covers.
Lay out old covers and measure. These new covers will be made with a centered vertical stripe pattern. The seat fabric width needed is 78 1/2" and fabric width is only 54" wide - the fabric will need to be pieced. One full width will be cut for center and one piece for either side (all will be cut 74 1/2" long). To figure the width of the side panels you need to match the vertical stripes and allow for seam allowance. Your new piece of fabric should measure 78 1/2" wide and 74 1/2" long. The vertical stripes should measure 74 1/2"
Serge or zig zag 74 1/2" edges
WST turn under one inch & stitch
On this one inch edge, center 64" of hook and loop tape - hook on one side and loop on other. Place hook and loop tape so it overlaps to close (always matching stripes)
With hook and loop tape closed at bottom and RST, seam sides
To form a box shape to hold cushion, fold all four bottom and top corners out flat and mark a line across where it measures 4" (should look like a triangle) and stitch the 4" line on all four corners
Turn right side out
The measurements for the back cushions on these covers were 29 1/2" wide and 43 1/2" long.
The vertical stripe would measure 43 1/2" long. The 29 1/2" width needs to be cut to match exactly where the stripes on the seat will sit. Once it is matched it is made exactly the same as the seat except for centering 21" of hook and loop tape.