Excellent. More great ideas.
@DaveInDenver thanks for the time on the calcs. This one is super touch to calculate because of the shape of the roof and it also depends on how the roof is oriented. I spoke to my neighbor who has a smaller, flimsier sunshade than mine, and he said he only anchored it with the drive stakes and little cables that came with his. That said, his is oriented uphill so doesn't capture much side wind from the west. Since mine does not have sides on it, it will also not capture as much side wind, but definitely more than his. I wanted to have sides to block more sun, but if I do sides I will only have them come down from the roof about 3 feet so that I don't add even more side wind load.
I'm thinking I like Martin's idea of heavy concrete anchors in the corners, and then use a couple shorter spiral anchors along the side to keep it from wanting to deform. That seems like the best of both worlds.
I had a problem a few years back with my solar panels taking off. I had welded a super heavy frame to hold the panels and thought the weight would be enough. NOPE! I came back last year and my panels had flipped over and flew about 15 feet away.
So, I made these stakes out of 36" concrete stakes, cut and welded. They have held the panels down so far.
The previous year, I put up one of those 10x20 covered carports from COSTCO. It ended up flying 30 feet into my RV and breaking one of the windows. The wind during the winter at the base of a 14,000 ft peak is legit!!! And we also get those straightline winds that are hurricane force plus.
Edit: The canvas shade I actually anchored each post with 1/8" cable pulls that I made...which might have made things worse because there was no stretch. So, it ripped stakes out and also ripped the canvas because it put the weak link where it shouldn't have been. The stretch of string wouldn't have saved things, but the cable broke things where they shouldn't have.
