I live in California and am required to build a deck with 1 hr fire resistance. We've been told that means steel, heavy timber, fire-treated lumber, or some kind of cement board covering the substructure. We were planning on fire-treated then found out that the cost of treated material is substantially higher than other materials. Now, we are thinking about heavy timber, but no one can tell us what dimensions that requires for joists or stringers. I'm even having problems getting the information from my City's building department. They're requiring it but don't know what it is they are requiring. Does anyone have a good resource for building fire-rated decks in California or can tell me what is required for the different elements.