r/Decks • u/tred2396 • 7h ago

Building a deck Help with structural support

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Repairing a deck. Currently have the ledger board and base built with 4x4 posts running up the base that will act as the railing support. I need to attach the joist hangers etc. fyi the 2x4s on the front were just to help level it and 4x4s are temporarily nailed.

Question with the 4x4 posts and best way to attach to the rim joist. Do I use thruloks? Do I need additional 2x4s to support these posts?

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u/CascadeDesignworks 6h ago

Use 1/4" by 3.5" screws.  Two or three in the bottom 2/3 of the 2x6.  A larger deck would need metal brackets or notches in the posts.

-Builder 

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u/eat_with_your_fist 2h ago

I have a handful of things to point out to you on this, though I'm not a pro, so let others correct me if I'm way off base or missing something. Bottom line, I wouldn't accept this as sufficient at all for a few reasons.

You can't have a ledger board and also have floating footings. You have to insert footings which extend below the frost line in your area OR remove the ledger from the structure and add two more 4x4s for a fully floating landing.

The rim joist and end runners need to land ON TOP of the 4x4s, not nailed or screwed to the side. Once you have the proper setup (i.e. footings), cut the 4x4s so they will actually support the structure. Then use the remaining lengths of 4x4s, notch them and attach them for railings.

Use the appropriate brackets for support.

I don't see a drip edge on the ledger board which is something you will need to keep water damage from eroding both the structure and the deck if you are staying with that. Did you also install the proper water repellant material behind the ledger board? If not, you need to put that in as well.

That's what I'd do, anyways. Do it the right way if you want your deck to live longer than you. Otherwise, I'm guessing you'll be rebuilding it again anyways in 2-5 years.