We have made several hoop houses, the longest around 20 metres. Used new materials, but they have long term durability. The hoops are 2" black poly pipe that slips over steel pickets at around 2metre intervals. The longitudinal are "Top Hat" steel ceiling patterns which cost $7 for each 6 metre length. We used second hand corrugated iron sheets around the bottom, wired onto the poly uprights. Winter conditions here in Queensland, Australia are not as harsh as USA so our coverings are hail netting on two and chicken wire on the big one. You would have to cover sharp ends for plastic. Mainly we wanted protection from marauding wildlife, but the added protection from wind and sun is also helpful. Our houses are 4 metres across, using 7 metre hoops, which gives us not only head hight but room to drive a tractor inside. We but a gate in one end, but the other end we have made removable to allow full tractor access, not that we have needed that yet.
