I have had multiple huts out there for 6 years now and this is what has always worked well, starting from the ground up:
Rebar stakes: half inch diameter, 2 feet long. I spray paint half of each stake so I can see when I have 12 inches below ground. If you are staking the standard 5 feet apart, they will hold. Don't need to cap them; the sharp ends might shave a bit off the inside of the PVC (check for curly white MOOP when you break camp!) but the PVC will not crack.
PVC should be Schedule 40, for strength. Length can be whatever you like. Cross pieces between hoops should hold the hoops apart (Ts & Xs or what you will) AND be held in place with bungees or strips of bike tubes. You want the frame to flex, rather than break, and pop apart intact if the worst happens. It is best and easiest to use individual cross pieces (rather than one long spine) and secure them separately. That way, the WORST damage you get from sustained high winds (a popped cross piece) takes 5 seconds to repair.
Shade cloth: the stretchy kind is best, as this allows for better flex. I use 70% aluminet, with a gap of about 12 inches at the bottom on each side. This reduces dust build-up and keeps the heat down. I can sleep until noon in my tent
and I need a blanket when I nap in my hammock in the afternoons. No lie. Aluminet is fantastic.
Ropes: I run a slightly stretchy climbing rope along the bottom at the sides, and secure to the end PVC. I bungee the shade to each PVC along the side, at the bottom. Aluminet will puff up with the wind but not sail, as it is open-weave. This is another huge advantage over solid tarps (not to mention the WEIGHT). If Aluminet is too $$$, black shade cloth works too, it's just not as cool in the day time.
I do not use any kind of guy ropes or anchors. I have never needed anything like that. The tension between the bent PVC and the rebar, the stretched cloth and the bungees will hold everything in place. I have watched these huts through some serious storms, and like I said, the worst damage ever took 5 seconds to fix. Good as new. My first hut is 25 feet long and has been a FANTASTIC home through 6 straight arrive-early-stay-late Burns.
The only parts I have replaced are some rebar stakes that bent in sustained high winds.
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