Hi All, I'm new to the forum and new to building a smoke house. I feel I've done pretty good but I'm come to a snag and I need experience to tell me the safest and preferably cheapest way around my current problem. Let me walk you through what I've done and we'll go from there. I'm building a vertical smoker, about 20"x20" by 4' tall. The frame is framed up of 1" boards with oak(pallet boards) at the outside. There will be untreated pine on the inside. The 1" space in between the inside and outside will be filled with sand. This is an electric controlled smoker with a 1500W element controlled by a PID controller. My dilemma...The pallet boards on the outside, while they look nice, they are not at straight as a board you'd go and buy. I have a couple cracks on the outside. My fear is when I go to put the sand in. It will all leak out the sides. I am looking for a cost effective non noticeable way to line the inside of the outside wall. My first thought was roofing felt? It's fairly cheap and easy to work with. I really don't have a second though. I like the roofing felt but I'm not sure if there is a safety problem or a heat problem there? Anyone have experience with needing a cheap lining? Thanks in advanced.