I have an existing concrete area approx 10'x16' at the back of my carport. I want to install a sun shade/sail over it and have some questions on installing the posts I need.

  • Can I use the existing concrete with either 4x4 or 6x6 post bases (something like the Simpson strong ties at Home Depot) with concrete anchors? Will this be strong enough? was thinking of using 10' long posts.
  • If I go this route, do I need to attach the posts with some type of header beam to deal with potential diagonal forces?
  • Or do I need dig new holes for the posts and use new footings?
  • 1
    Welcome. You might revise a bit to describe the posts and shade design. The overall weight of the thing has a lot to say about answers to your question.
    – isherwood
    Jun 23, 2020 at 21:04

1 Answer 1


There are no reasonably-priced post bases that will support your structure in that way. The post bases you describe are not intended for that purpose. They merely maintain post location and keep them off the concrete.

You need to either set the posts in the ground (to a depth of about 1/3 the above ground post height) or build enough diagonal bracing into the structure to make it free-standing. In the latter case you'd still want to anchor it to the ground to prevent lifting and tipover due to wind.

  • 2
    Local building codes may have a say in this as well, is generally frowned upon for your flimsily anchored carport to lift up in a strong wind and become a projectile.
    – JRaef
    Jun 24, 2020 at 0:30
  • Generally, @JRaef, exceptions are made for tornado and hurricane force winds, though.
    – FreeMan
    Jul 23, 2020 at 23:32

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