My own 2 cents worth on greenhouses is to build them with used patio doors cheap got mine for 5 at restore and to be careful of snow loads and sliding snow.
Building a greenhouse with patio doors.
Building a greenhouse linda holliday recycled patio doors in the 1960s my father spit out the word plastic as if it were poison.
Sliding glass doors cover such large areas that it can be very handy to construct the greenhouse using these materials.
I ve got about 8 3 x8 patio doors at some precarious horizontal angles on the south west side of my greenhouse addition to my passive solar home.
The east side has a homemade wooden door and another used window about 3 feet wide and 6 feet tall.
A greenhouse can be built from recycled materials including sliding glass doors removed from other buildings.
Also non frosted shower doors make great entry doors.
It s easy to cover clear glass with tinting or frosting if the greenhouse will hold too much sun.
For a backyard greenhouse project finding a door that fits your own design may prove difficult.