What ever you use it must be flame retardant. Here is a link to a story that you should see. Just because it is a PTA event there needs to be care taken to make sure it is safe. Try to see if a local haunt my loan you some walls they are not using, I know some have old walls that are a little run down that just sit. Good luck.
http://www.sfm.illinois.gov/document...0Buildings.pdf
Phatman




