So, first, I just draped a piece of bleached drop cloth over my bench and trimmed it until I had the right size. I wanted it to hang about four inches down, so I would have plenty of material to attach the ruffle to.

Keep trimming until it looks even all the way around. You can see how precise I am with my measurements.

Pin it with a fold in all four corners until it fits snugly.

Now, this is the step I would have done differently if I had known I was going to add the ties.

The fold faces outward. Well I wanted them to both face inward, so I could sew the ties into the folds.

Next, sew folds down on all four sides.

This is the part where you should sew your ties in, and not later when I did it!

Next, cut two strips of bleached drop cloth 60″ by 1.5″

Fold them in half and sew all the way down.

Press them flat and top stitch all the way around, folding the ends under to hide the raw edges.

Cut them both in half, so you end up with four ties each 30″ long.

Next, cut out the ruffle pieces.

I made them 6″ wide, but the length will depend on the size of your bench. So, if the diameter of your slipcover all the way around is 180″, your ruffle piece will need to be 270″ long.

Since I didn't have a piece of drop cloth that long, I sewed several sections together.

Place a gathering stitch in all the way down and then pin the ruffle piece to the main slipcover piece.

I brought it back to the bench and readjusted to add the ties.

I just ripped out the seams and pinned them back in the right way, with the ties.

I stitched the ties in.

Next, serge all the way around the bottom of the ruffle to finish the edge and hide any loose strings.

If you don’t have a serger, you have two options: you can either use a zigzag stitch (or any other finishing type of stitch your machine offers), or you can just hem the edge by pressing it over 1/4″, and then another 1/4″, to hide the raw edge inside. I didn’t want the hem to be too bulky, which would cause the ruffles to lay funny.

Next, fold the serged edge of the ruffle over 1/2″ and sew it all the around.

Place it back on your bench and tie the slipcover. Adjust if needed.