I have a rental house built in the 70's that had severe water damage in the small room (4x5 feet) that houses the hot water heater. The room is off of the garage. I've had the water heater replaced and removed the dry wall. I'm getting ready to replace the drywall, but I'm concerned about what is the proper product to put back on my walls. Is 1/2 inch drywall adequate or should I put heavier dry wall back up?