What warp the floor?
Most of these reefer floors are treated already, so I would say with the normal wear and tear, a washout is not a problem. However it you use a power-wash to clean before treating the floor, then I would use a good soap with hot water and them run the reefer to pull a lot of the moisture out of the air with the box shut.
Reefer boxes as per Kidron are made to be washed out, so I would not worry about getting things wet in there. I would also suggest calling the manufacturer and asking them what can be used to treat the floor.
You own the truck?
IF not have the owner have it done.