Wood post height vs dimensions for supporting girder beam in basement



I have a fun one guys! These are support posts from concrete pads up to the girder beam above that support the floor joists. They are 6x6 treated posts and one of them is over 15 feet tall. I’ve already recommended adding mounting brackets for where the posts meet the beam but I’m concerned the taller posts are not big enough to provide adequate support at that height and might bow under weight. Does anyone know a source that details height to post/column widths?

Fun bonus, the framers used common bright nails in treated wood to toenail the the top of the posts to the beams above.

Yes, an engineer…

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You were right to call out the missing brackets. May just be the angle, but looks like those posts are warped and twisted already. How were they attached at the bottom?
Also from here it looks like those bottom plates are not treated?

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They do have some warp in them to start, good luck finding a 6x6 that’s straight off the rack much less when they dry out! I believe the bases are Simpson post bases that are rated for outdoor use and are nailed through the holes but I’ll definitely confirm that if possible. Thanks!

Right? Especially at 15’!
I dont think I would be concerned about the length of the posts, as long as they are properly attached at each end, unless there is obvious warping. But it would take significant warp or twist to affect the integrity, and lead to worsening. But only time I see them that long is under a deck, but those are not bearing as much weight

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That is what I find interesting here under the house. I haven’t had time to look up max post height (if IRC even addresses it). But I did find this for decks. IRC 2018

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Thanks for the info Brian! I think I’m going to reach out to an engineer or architect to get something official before I cause a scene. If a 6x6 can’t go 15 feet up for a deck surely it can’t got that far as a main floor support for a 2 story home.

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Thanks Daniel! The dead load is what worries me since this is a 2 story 3,500 square foot home one a hill side. I really which they would have used foundation pads with block instead of wood 6x6s.

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If I found this in my area it would have to be verified with the building plans. We use steel columns here to support main beams. At best what you have pictured would be temporary supports.

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The whole setup looks a little odd to me. There are two LVL beams intersecting at the left column, which could be a significant load needing a substantial footing. That right column seems out of place that close to the end of the beam. Doesn’t look like it would be needed, if the LVL was designed properly. All the 6x6 should have the appropriate bracket to connect to the LVL and the two LVLs should have the appropriate bracket connecting each other.

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Randy, any reason, other than cost, to use wooden posts instead of steel?

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Randy, I don’t like the look of any of it either. Apparently the original plans called for this space to be filled and have a slab on top but the builder switched it up and half assed the new plan. I’m getting in contact with the city inspector to see what they think about it. I’ll post any updates here for anyone to see.

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