Inexpensive Polycarbonate Greenhouse Build part 1

This video is part 1 in a series of videos showing how to build a polycarbonate glazed greenhouse using a high-tunnel frame. Typical high-tunnel greenhouses use polyethylene film, which easily tears and rips off in this region due to the intense wind and flying debris. This area is also prone to late spring and early fall frosts which destroy crops in high-tunnels using only one layer of polyethylene. Another downside of polyethylene is that it requires replacement every 4-5 years, which is labor intensive. The initial seemingly low price of polyethylene is offset by its short duration and frequent replacement costs.
The solution is to use a polycarbonate skin; however, polycarbonate cannot be fastened on typical high-tunnel frames because the polycarbonate is too rigid. This video shows how to build frames that can have polycarbonate applied to them.
The added purlins and polycarbonate this frame requires doubles the price of this project over the typical light-framed polyethylene skinned high-tunnel, but still provides a price point that is less than 1/2.5 the typical polycarbonate glazed high-tunnel from companies like Conely's. The high-tunnel in this video is around $11.50 a square foot for the kit, and is 26.5' wide by 34.5' long. The end walls have a fixed cost, so going longer will result in a lower price per square foot. This kit can be added onto in 7' increments. This particular greenhouse takes one person that is knowledge in construction, with a helper to assist in lifting things, about one week to complete the build.