I'm currently replacing a slightly above ground level deck that rotted. The deck will fit between the house and a flag stone patio. One edge is tied to the house via a ledger board. I would like to incorporate two 6X6 post into the construction for a sail shade while also using the post for the corner support. 
The post will extend 8ft above the deck surface. My question is can I use those post for the corner support and if so, what is the proper way to attach to the post?
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How deep will the posts be buried? What size are the deck runs?– JACKCommented Apr 17, 2020 at 12:55
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You're going to have some settlement if you're using a post with no foundation. This can pull the deck away from your house and lead to damage at the ledger connection points.– represtonCommented Apr 17, 2020 at 13:18
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My plan is to sink the post 4 feet into the ground (post are 6"x6"x16'). I plan to prep the hole with 4-6" of gravel, set the post, and pour concrete. I'll cut to length once the concrete is cured. My deck runs from where the post would be set to the center brace beam are about 7'.– JoeCommented Apr 17, 2020 at 13:31
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What size planks will be attaching to the 6x6's?– JACKCommented Apr 17, 2020 at 13:58
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Can you upload a sketch of your framing plan? Lengths of the beams between the posts and joists between the ledger and the beam would be helpful for a quick check of everything.– represtonCommented Apr 17, 2020 at 14:04
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2 Answers
No. Deck beams must have bearing (direct support underneath). They can not be supported via side connections.
It looks like from the image that you are trying to support deck beams on the 6x6 post without bearing at the post. If these are meant to be beams then they must have something under them at the bearing point. A side through bolted connector for a beam to post connection is not approved for decks. I assume that the reason is the through bolt connection or wood could degrade under weather and is much safer if it is actually resting directly on a post (still requires connections).
The following guide lays out how to design/size beams for your deck in a prescribed manner. The joists that span between beams can be connected via hangers and don't require direct bearing (something underneath). If you vary away from the prescriptions in the guide then you'd need an engineer to approve of your variations.
See figure 9, prohibited post to beam connection.
https://awc.org/pdf/codes-standards/publications/dca/AWC-DCA62015-DeckGuide-1804.pdf
Probably the best thing to do is to upsize to 8x8 undressed (not nominal), then notch the post for direct bearing of a single beam. I am assuming just a 2 member beam so you'd have to integrate that into the spans of your deck. The joists that span between this beam and your ledger do not require direct bearing (see figure 8A). Then to prevent a weak area in the 8x8 I'd get a 2 pieces of 1/4" thick steel 3x the height of your beam so if you have a 2x12 beam then 11.5x3 = 34.5". I'd take the steel and laminate it on the beam notch side and the non notch side and bolt it together that way any forces from the sail or your railing assuming you are integrating a railing are transferred past the weak spot in the post.
Good luck.
answered Apr 17, 2020 at 14:47
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I agree, prescriptive design (AKA doing it yourself) limits the number of ways you can do this. Commented Apr 17, 2020 at 15:00
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This could use some more detail. I don't know what "must have bearing" means.– JPhi1618Commented Apr 17, 2020 at 15:33
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The OP doesn't mention the footing and is asking for help about the connection, the link to the deck guide and the need for a footing is more of a comment than an answer, unless this was expanded on to explain– AckCommented Apr 17, 2020 at 15:38
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Sounds like @FreshCodemonger was referring to the OP's drawing, which shows the deck's horizontal member being attached to the sides of the post, which means that neither of them has any bearing support. What the OP should do is build the deck so that at least one of the horizontal members is bearing on the post, and flush with the side of the post, and fasten the post for the sail outside, with a lap joint.– HuesmannCommented Jun 25, 2020 at 15:36
installing wood into concrete? best to install concrete with metal footer potentially Simpson, insert the 8x8 like suggested and notch for load bearing.. metal bracketry only is setting you up for failure
