Hey everyone! I'm working on setting up a 20'x16' shade sail in my backyard to cover my patio and surrounding yard. I'm planning to attach it to my house on two corners and use 2.5" square 11 gauge steel posts, standing 11' tall, for the other two corners. I've started digging down about 32 inches with a 6" diameter hole to add some gravel and cement the posts in, but since I live in Las Vegas, the ground is super hard and filled with rocks. I rented a two-man auger but could only get around 15 inches deep before it got stuck. I'm considering using a jackhammer to dig deeper, but my dad suggested that I could just use the current depth and create a faux planter box filled with concrete, reaching another 24 inches up. Would that work, or is that not enough strength for the posts?
3 Answers
I get how frustrating it can be! Shade sails do put a lot of lateral force on the posts. Generally, I’d recommend embedding them 3-4 feet for stability. Honestly, I’m not too keen on the planter box idea—it might not hold up against strong winds.
It's really crucial to consider how these posts will handle forces, especially with wind! A faux planter might just slide away if conditions get rough. I dig mine deeper—like 4+ feet when I lived in a place with rocky soil. Can you test the stability before finalizing? Just give it a solid pull after installing to see how it holds up. Better to be safe than sorry!
Great tip! I'll definitely consider that before I make a final decision.
Just to add my experience, I went for 48 inches deep and used 4x4 posts reinforced with concrete. Trust me, those sails can knock over even a heavy planter if it's windy! I always feel better overbuilding than risking a disaster later on.
Totally! It's not easy getting it right, is it? Wishing you the best with your setup!