[bold]Background[/bold]<br>As I noted in an earlier post, my asthmatic son's attempt at sleeping in his Wilderness Survival merit badge shelter ended quickly when he started to develop a wheeze. The shelter, as taught by his councilor, was a single ridge pole against a tree with smaller branches laid across to make a grid of support ribs. Hemlock branches and a layer of dried leaves completed the roof. I knew this material would be a potential problem so I alerted the camp medical officer (a paramedic) that we may end up knocking on his door that evening for a nebulizer treatment (all medications are stored and locked at the camp medical cabin). I intended to stay up later than normal that evening at the troop firebowl so that I could check in on him later on. But he lasted only a half hour before the wheeze developed. Fortunately he's experienced and mature enough to recognize and act upon the symptoms of an early attack. He was fine after a few puffs on his inhaler and he returned to bed.<br><br>[bold]The Problem[/bold]<br>Because of his asthma, an ad hoc shelter out of natural materials is unacceptable. Hence he needs to make sure he carries suitable material with him on trips in case he ever needs to make a shelter. I know that alternative shelters can be constructed out of rain ponchos, heavy duty plastic bags or survival/space blankets. Assuming that one would tend to use the poncho as a ground cloth because it's more durable, which of the later two would folks prefer for the roof? Also, are any particular brands better than others, both for the garbage bags and the survival/space blankets.<br><br>