Welding on a painted floor - ideas?

[davepl]

I'm doing subframe connectors on my Camaro, and it will entail a lot of welding under the car (mostly MIG). Unfortunately I just had my shop floor coated (that speckle finish) last fall, and it's not burn proof.

I'm wondering what I can put down on the floor that will protect it. I was thinking perhaps a sheet of plywood that soak with a hose first, but slag will likely still ignite it. Perhaps drywall (gyprock), but that has a paper coating.

Obviously a big sheet of steel or a pile of sand would work, but those aren't really practical, so I'm looking for any good suggestions!