I am a landlord of 43 yrs. I enjoy rehabbing older houses. Regards porches, for over 43 years, I have had bad luck with tough-in-grove high quality pine, porch floors. At several locations, I've gone to replacing deteriorating tough-in-grove porch flooring, with 5/4 deck planks. In 5 locations the 5/4 deck approach has lasted 20+ yrs. A few years ago, I was confronted with the decision to go with 5/4 or try tough-in-grove (t-n-g) again. I talked myself into believing that my bad experience with t-n-g was because I was "cheaping-out" on material quality. So, I went to a well established lumber yard in Kansas City (in business 50+ yrs. ---NOT a box store) and asked for the best t-n-g porch flooring they had. --Less than 4 yrs. later, the porch flooring failed. Ok, 5/4 deck planks have proven to be a great long lasting solution; however, I worry about a potential problem. Problem: I am constantly concerned that one of my smoking tenants will carelessly drop a cigarette down, between the 5/4s ---thereby staring a fire under the porch. Question: Is there a surface material that I can put over the very sound 5/4s, to eliminate the spaces between the 5/4s?? Obviously, this material could not be a layer of galvanized metal (too slippery in winter). ----and don't suggest t-n-g pine. Ok, you know the situation ---any suggestions/ discussion, would be most appreciated. ---Jaes.