Does anyone have any advice on how to build a greenhouse that will withstand snow on the roof and will also allow the snow to slide off? (We have building codes of 200 lbs/sq. ft.). But the snow needs to get off to let the light in. I’m not sure what kind of material would work.<<<<
I do not have knowledge of real snow, but if you check the solar greenhouse books, some will show the angles to build and they are often steep enough slopes to slide it off, due to the slope.
I like mine attached to the house, and you will get heat from it, if you open a window or door.
How about half an “A” frame, that will slide it off, there are some new coverings that I do not know about, but the old clear corrugated fiberglass works well too, it is what I used.
Never use the brown or red tinted fiberglass, as it cuts the ultra violet rays from the sun, that the plants need.