Mine is a permanent 4'x6' wall- 1 sheet of insulation glued to a piece of plywood screwed into the wall. I cut the sheet of insulation about an inch bigger than the board which allowed me to wrap batting around and tack from the back. Looks great and cost about $30. The only caution is to use very fine pins so the insulation won't crumble. Actually, it works so well that I rarely use pins anyway!