Should I build a greenhouse?

[newbury]

You probably can achieve the same thing with concrete wire mesh.

The concrete wire mesh I'm familiar with comes in rolls and is a thinner gauge. The panels are usually 6 gauge or better. They even make "bull panels" that they advertise as 1 gauge, but I don't know how easy they are to bend, the cost or where to get them in my area.
One of the attractive things to me is the ability to make a "greenhouse" with minimal fuss.
I'm still waiting for someone to market a plastic that you can just blow a greenhouse like children make long bubbles with soap bubbles.

By Rror - Own work, CC BY-SA 3.0, File:Professional bubble.jpg - Wikimedia Commons

 

[MossRoad]

I'm not worried about the poles collapsing. I'm worried about the plastic breaking under the snow load. That's on the car shelter greenhouse.

 

[MossRoad]

On the cattle panel hoop greenhouse, we did that as a bean trellis. No plastic. It worked great. One winter we had 20" snowfall, wet and heavy. It managed to span the openings in the cattle panel and build up. That collapsed it. So now it has supports on each end.

 

[Jstpssng]

I'm not worried about the poles collapsing. I'm worried about the plastic breaking under the snow load. That's on the car shelter greenhouse.

If you buy greenhouse plastic thar shouldn't be a problem. CoolMax 4 Year UV Open & UV Resistant 6 mil Clear Greenhouse Covering | Farm Plastic Supply We used to change it every 2 years when I was younger, but that was on wooden frames. They've likely improved the UV resistance in the last 45 years, this is 4 year plastic. My father gave me his last hoop house, 14x40; as well as enough used plastic to cover it. Instead I cut the plastic in half and only put up 20 feet of it. The plastic was on for 2 years before it came off in a windstorm. I dug out the section section... only to find that mice had been all through it.

There is a difference in quality between buying from a greenhouse supply company vs going to HD.