I purchased an Avalon 796 stove for my log cabin. I have been going thru the manual checking clearances and have a couple of questions. First off with regards to floor protection the manual states non-combustible material with a minimum thickness of 26 gauge floor protection. What does that mean? I plan to build the hearth and want to be sure I'm meeting all requirements. I had planned on using 3/4 in plywood then 1/4 inch wonderboard topped with porcelain tile. Any suggestions?