The roofing is 3.5mm Solexx double walled polyethylene. It has an R-value of 2.1, 77% light transmission, 100% light diffusion, and only costs $1.55 per square foot. It is by far the most cost effective glazing solution that I've come across. It has a 10 year warranty, lasts 10-20 years, is as insulative as triple walled poly-carbonate, yet is only a fraction the price. Furthermore it can be lapped, meaning you don't need to buy H-channel and U-trim (an added expense of poly-carbonate). And it comes as a roll, reducing the cost of shipping and making it easier to handle and store. You have to order it through one of their dealers but it ships quickly and cheaply. I am one of their dealers and am happy to offer a discount for all the Permies out there, just let me know your on Permies at the time of order.
If we don't do the shopping, we won't have anything for dinner. And I've invited this tiny ad:
It's like binging on 7 seasons of your favorite netflix permaculture showhttp://permaculture-design-course.com/