I Was getting 6+ years out of it single layer...until we had 50+mph winds...
and I didn't have it as secure as it should have been either.....
Strips of wood of some kind yes, about 1-1 1/2" wide. have a bunch pre cut. I used roofing tacks, wide head, (not too short), easy to hammer in, pry off whole strip if need to reposition.
Here's a couple things might help....you'll need some rope. Enough to throw over the GH, tie off at both ends, every 10-15' or so down the length of the house.
Pick a non windy day. Gentle breeze fine, windy not good.
Unroll (if it's new or in a roll) plastic and lay lengthwise along the base of the greenhouse on the side any breeze IS coming from. You want to pull it over the top with its help, not fighting it.
About every 10-15' double the plastic over, about 12" or so, then fold in again over a smallish object like a tennis ball. Something not sharp. Then take a good length of rope, a good size to throw and pull the plastic with, and wrap and tie it around the object. What you're doing is making a pull point on the plastic without hurting the plastic. Throw all the ropes over before pulling any. If you have someone to help it easier to unhook snags, have a long stick handy. Pull the rope at one end ONLY until you feel resistance, then tie it off and go to the next one. This way you don't lose it if the wind does come up, but you're putting the least stress on the plastic.
After you've worked it all over the top, adjust your sides so you have enough to fasten, or attach to a pole you can use to roll up the side like a curtain in the summer for extra ventilation.
Throw all those ropes you used back over the top and fasten at both ends to hold the plastic down while you work on the wood strips.
To make the inflated part, pull the second plastic over the first (remove the ropes first) and replace the ropes over the top. At the top of the sidewall on the outside, you'll want to nail strips of wood end to end lengthwise down the whole side of the GH. I wouldn't inflate the sides unless you can shut off the air to them for summer so you can roll the sides up. You will need an electric squirrel fan and a collar to hold the plastic to it, to keep them inflated, insert that from the inside cutting only into the innermost layer of plastic. They (the fan) don't take much power, maybe solar would work????
How soon you thinking of starting this, this weekend? There's more, but I thought this would get you started......
Questions welcome
Rereading what you said, if you tack the first one that's fine unless you lose power to the squirrel fan and the outer one chafes over the tacking mechanism of the inner one. I've never lost power on a windless warm day......
