I am trying to install 4x4 wood posts to hold up a rectangular shade sail on my rooftop. The posts will be free-standing with nothing attached besides the sail.

Ideally, I would be able to attach them to the top of the half-walls. The top of the half wall is one layer of brick (that is covered in a little concrete or something) on top of cinder block. I think a 6-foot post will give me the right height, but I am worried about the brick breaking and the post falling 7 stories and killing someone on the sidewalk.

Please help me do this safely.


Use Simpson Strong Tie E-Z Base with a 1/2-Inch by 3-3/4-Inch Bolt Wedge Anchor for Cracked and Uncracked Concrete.

I also think I would have a back up cable attached to the wood and cinder block just in case, but I have literally zero experience in this type of installation. Below are pictures of my place. Any input is MUCH appreciated!


Simpson Strong Tie STB2-50334 1/2-Inch by 3-3/4-Inch Bolt Wedge Anchor for Cracked and Uncracked Concrete

post spot in red

brick view

  • I would think you'd want to go with a longer threaded stainless steel rod and drill down into the concrete. I'd have the same concerns about the top brick layer breaking off. How big is the sail? – UnhandledExcepSean Jul 20 '18 at 18:31
  • I have two 16x16x16 triangular shade sails and the mount points do take much stress in wind. My mistake first time around was buying amazon’s suggested wire rope, which came down in the first storm, after upgrading to heavier gauge its been fine. Wind does create much stress tho. – Tyson Jul 20 '18 at 19:17
  • Thank you for the input! The roof dimensions that I am covering are 19x12 so i got a 16x8 sail and I got a pretty heavy-duty wire set. How far into the concrete portion do you think I should go? like 2 inches past the bottom of the brick layer? Also, what is the highest you would make the post? I was thinking 6 feet and then attach the sail around 5 or so. – nycDIY22 Jul 21 '18 at 16:17
  • I would think that would be ok, but I don’t have numbers to back that up and I’m not a structural engineer – UnhandledExcepSean Jul 22 '18 at 2:08

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