Sorry Patrice, I didn't keep track, but I think it took about the same as a normal quilt when doing the QAYG block method. I used the same color sashing for the front, back & sides.
I guess you could figure it out by (1) multiplying the # of blocks by the block size, (2) multiplying the # of sashings by their sizes (front, back, sides & between the blocks) and (3) adding these amounts together to get the total # of inches, then convert to yardage.