Fourth or fifth the recommendation for Primo Pads. If that doesn’t work, I once saw instruction for making a pad on Belg L list serve. The jist of it is:
[I]Take a piece of 1/4 inch or 3/8 inch plywood cut slightly smaller than the bottom of the crate. (Originally we used masonite but I couldn’t find any for the last iteration.) Cut a piece of dense 1 inch thick foam rubber the same size. Stretch tightly a piece of very good quality naughahyde over the foam and plywood and attach to the back side of the plywood with staples. Put pad in crate - it should fit snugly.
The pad is soft enough to cushion. Has just enough give for toe nails to dig in when needed to balance. Washable. Yucky stuff rolls off. Can’t be scrunched up like a cloth pad. No easily chewable edges.
Instead of doing it all myself this last time, I had Home Depot cut the plywood to size. Bought the foam rubber at a fabric store. Brought both to a car upholstery shop and had them supply the naughahyde and labor to make the new pads.[/I]
Buying a Primo Pad sounds a lot easier!