I'm working on an existing wood framed building. In order to meet chapter 10 of the existing building code a sprinkler system needs to be added. The fire pump room is located on the lowest level with a floor above. What is the most economical way to achieve a one hour horizontal separation for above the fire pump room? Most of the floor/ceiling assemblies I can find require a topping mixture between the finished floor and the subfloor. It would be preferable to not have to do any retrofitting to the floor above. I would appreciate any suggestions! Thanks!