Help: I need Fire proof/retardant material for exterior patio.?

I am turning a covered patio into an outdoor kitchen and was instructed by my contractor to obtain either "masonite siding" or " concrete board siding", neither of which I can find, at least not by those names. Anyway, what can I use and where can I get it? Preferably an online source with delivery, as I live away from stores, but I can manage a trip if needed.

I do not know what degree of heat this area will produce or be exposed to and I am open for ANY suggestions as to the set up of this whole thing. I want to install a stainless steele wall mounted hood going over a traditional outdoor gas grill. I plan on having 3 different gas powered cooking devices set up to use: grill, big gas burner for crawfish pot and small gas burner for wok. I am sure all three devices will never be used simultaneously, but possibly two at a time.

Would there be some sort of fire proof/retardant spray-on material I could get? The patio is only 6 months old and does not even have anything other than the plywood for a ceiling right now so there is no existing material to remove or maybe even to cover.

We have already used the crawfish burner 4 or 5 times under the patio and it does not seem to produce any type of threatening heat or flame, however I just want to make sure my house does not go up in flames the first time I turn the grill on. It will be a nice, big grill....not sure of BTU's or anything but its one of the biggest you can purchase at a retail home quarters store.

ANY help is greatly appreciated.