simy1 wrote:
The neighbor has two 40X40 (all units in feet here and after) sheets
of clear poly that he will give me, since he sees that I have tunnels
for my winter vegetables (this year I will get to harvest until end of
january at least, he actually told me as I was getting back into the
house with a paint bucket full of just picked radicchio). I just love
these hot stove projects, but before I embark in it, a question or two
for those who have built hoophouses.

1) those sheets are clearly very large. If used without cutting, they
will cover a 24X38 area, with a maximum height of 12. That is an
unusually wide hoophouse.

2) I think I want to use PVC pipes, glued with plumbing solvent. The
question is, can I make them withstand a windstorm or snowstorm. I
have seen lots of pages on the web, so I have seen what can be done.
Amongst other solutions, I noticed that there were hoophouses with
poles supporting the central beam, and of course one can always anchor
the hoops to the ground. I guess I am more concerned about the snow
than the wind.

3) I am thinking about getting a double layer of poly for extra
insulation. Any experience with that? I would need a double hoophouse.

4) I plan to make two trap doors at opposite ends, and have one set of
doors with poly and another with chicken wire. Will there be enough
ventilation with the chicken wire doors in place?
Before you start building with PVC take a look at this hoophouse:

http://www2.moment.net/~wingnut/hoophouse.htm

Bill