Another consideration is wind. A breeze blowing over the platic sheeting
will set up an instability, just like a flag flapping in the wind, and the
sheet may get torn to shreds. Also make sure the house is *strongly*
attached to the ground, otherwise you have just made a curved wing
surface that will want to take off.
When I make my hoophouse it will have plastic sheet as the "glazing",
but only temporarily. I will replace it asap with fiberglass sheeting
because that stuff is much more durable.
B