This is a bad idea, making a wall like this outside and a way from the guest is one thing but making a tunnel out of it and in doors is not a good idea. If that stuff cought on fire it would go up in seconds and would give off a toxic cloud. If you are charging to get in, there is no way it would pass inspection. You could make your walls out of door skins. They cost $9.00 ea. Start small and build it bigger every year.