Yeah, I made the mistake of torching some brackets off of an 8.8 and burned a hole in my epoxy. Looks like crap now. Also depends on how close you are welding to the floor. I found if I am welding up on the lift, there is very little damage to the floor, but if I am welding on the floor or close to the floor there are black burn marks all over it. I'd say use a welding blanket on the floor to protect it. jmho.