Greenhouse: Greenhouse Design Help Please!, 1 by RooDogMN

RooDogMN wrote:
I have a bit of an off the wall idea and wanted to run it past those of you with experience.

The wife and I have been thinking about making our 3 season porch into a 4 season porch and screening in the area underneath it instead. I\'m wondering if, in the winters, I could frame up polycarbonate panels around this lower section and use it as a greenhouse. I could then remove the panels come spring and it would still be screened in for summer use. My thinking is that it not only provides a place for plants/small trees in the winter but would help keep the room above it a lot warmer as well. That porch area faces south & west and the sun covers the whole slab for most of the day.

The plan is a lean-to style greenhouse wall like the one pictured. The red crosshatched section in my picture would be sealed up/sided when we close in the upper porch so I figure I could start the lean-to polycarbonate roof there which would stay in place year round, the vertical wall under it would be wood framed & screened and then I can put up polycarbonate panels on those walls for winter.

My question is, what\'s the best choice for greenhouse material given this situation? I\'ve been leaning toward the 25mm triple walled polycarbonate but don\'t know if that\'s the best choice, overkill or if there\'s a better solution. The greenhouse add on section would be open to the area under the raised porch making one big open area. I\'ll have a space heater to keep it above freezing as it not only helps with the plants but any extra heat below means less cold air leaking into the new 4 season porch above. I\'m in MN, zone 4b.

Thanks!