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I'm a new homeowner with DIY enthusiasm to improve the outdoor living space. Recently completed build my fence now planning to do a pergola first and then add deck to it so we can enjoy some outdoor space. I have a question about pergola post where instead of concrete footings can I lay 6x6 or 4x6 lumber on the ground with gravel underneath and secure them by driving 12 or 24 inches rebar through wood into the ground and attach the 4 pergola posts to them using bolts. Our winters temperatures generally get down to -5f maximum and we see winds with maximum speeds to 60mph. I have seen videos on YouTube doing this using some fancy connection hardware but I thought using bolts should work. I ask this question as later when I do the deck after pergola it would be a bit easier to build deck. The size of pergola will be 10x10. Any thoughts would be appreciated.

Here is a link to one of the videos I saw on Youtube Pergola Post attached to ground lumber

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You say you get winds up to 60 MPH but you don't see a need to have a tall structure anchored in concrete? Sure, most wind will likely whistle right through an open(ish) pergola, but all it takes is one good gust, square on the flat side of the roof joists, and it'll blow right over.

Even if you were to thread the top of the rebar and use nuts & bolts to hold the lumber to the top of the rebar, a 24" piece would pull right out of the ground with a 60 MPH wind pushing on an 8-10 foot tall lever. Additionally, rot (even with pressure treated lumber) will enlarge the holes in your sleepers and the fit between the wood and the steel will get sloppy. The rebar will rust, exacerbating the issue.

I've used rebar through holes in treated landscape timbers as edging for my gravel driveway. I've had to replace the lumber 3 times in less than 30 years. The timbers laying on the ground (granted, they weren't carefully installed with gravel for drainage, but still) rotted out to the point that there was not much left of them. After picking up chunks of rotted wood, it just took one or two hits with a 2 pound hammer to loosen the rebar enough to pull it out of the ground by hand. A perfectly acceptable installation method for something at ground level, but I sure wouldn't want to visit your house knowing that this was all that was securing hundreds, if not thousands, of pounds of lumber over my head.

There's a reason you see people using "fancy connections": A) it's required by code, and B) it's safe. Note that code is often "written in blood" - accidents have happened; engineers have studied what caused the failure; code was updated to require a minimum construction to prevent that kind of failure from happening again.

Frankly, renting a powered auger to drill a few holes for footings (be sure to check for buried utilities before drilling), getting them drilled to below the frost line (again, be sure to check for buried utilities before drilling), inspected (if necessary in your locale), filled with concrete and setting post anchors in them is far cheaper and simpler than the potential damage to people and property if this should fall over. Think of the hospital bills on top of the house repair, and possible lawsuits from people you thought were your friends, should your short cut method fail.

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  • I would also focus on the code issue as the wildest thing I have watched is a little larger structure 10x18 ? 8’ tall lift off the ground hit some trees and land in the neighbors yard upside down the blocks it was built on were just set in place and I think all but 1 maybe 2 survived the crash still hanging onto the bottom plate. This did not have a deck the structure had been there for years and when the neighbors went to rebuild he had to put in ~36-48” deep footings where the original pier blocks were. No one was outside but that could have hurt someone.
    – Ed Beal
    Mar 25, 2021 at 15:34
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    @freeman Thank you so much for the detailed explanation
    – Krishna
    Mar 25, 2021 at 16:25
  • @Krishna you're welcome, and I'm glad you took that the right way. I know it may have come off a bit harsh, but there's far too much that could end catastrophically to rely on just a bit of rebar. Your deck, if not attached to the pergola and set basically at ground level, can get away with being set on deck support posts (if allowed by local code), because it'll be heavier and, being lower to the ground, much more difficult for the wind to lift. If you need to place footings for it, though, think about doing that at the same time as the pergola footings.
    – FreeMan
    Mar 25, 2021 at 17:50
  • @FreeMan Thank you're for elaborating. i understood the essence of what you're trying to say. Deck would be ground level raised about 8-10 inches off the ground. i was planning to use deck stones to level & support and attach to the pergola posts where possible as the deck would be just wrapped around pergola.
    – Krishna
    Mar 26, 2021 at 12:48

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