Stall mats. They're heavy carbonized rubber, around 3/4" thick.  We use them in our platform kennels to cut down on drafts, protect the wood, and make a more comfortable surface for the dogs. Around $40 for a 4x6 heavy stall mat. They also come in 2x4 size.  Do not get the ones with a pattern on one side. Flat smooth surfaces are easier to clean. Dogs CAN gnaw off a corner, but it takes a very long time and a lot of determination. These won't tear up quickly. I like the larger ones because there are fewer seams when you put them down, but the smaller ones are easier to handle.

If you're going to have stall mats, then you're going to want some vise grips to move them around, because they are heavy and there is nothing to grab. Don't skimp and get the cheapest ones, they won't handle the weight and the gripper caps will pop of. Get the metal ones like these. 

Do I have to mention zip ties (variety of sizes), bungie cords, and tarps? Didn't think so. 

 

Stall Mats Vice Grips
ARI Stall Mat ARI Vice Grips