I use one board. So far no problems. I think the most fabric I've wrapped on the boards was maybe 5 yds and I may have used two boards for that one. On smaller amounts of fabric (less than a yard) I cut the boards in half and use them that way. I use the larger board - I believe it's about 11" high by about 9" wide. I really like the way they look on the shelf and how much easier it is to retrieve the fabric. Right now most of my fabric is folded on the shelves, but I'm working a little bit at a time to move it over to the comic book boards.