Hi,
I’m replacing a swinging driveway gate that has broken and/or sagged multiple times. It’s on wood posts set in concrete now.
I would like to grossly over-engineer this, so that I never have to mess with it again. Fence is 6 feet high, and heavy wood, 4 inches thick.
I’m thinking about replacing the wood posts with steel posts set in concrete, but I’m not sure where to find 4×4 heavy steel posts. Any recommendations? Do any big box stores stock these? I’m thinking 3ft in the ground with 6ft exposed, so 9ft length total.
Also, any particular heavy-duty hinge recommendations?
Thanks!
Zach
Santa Cruz, CA
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Prescriptive codes don't address the connection at less common angles, so base the connection off more typical ones using bolts, structural screws, blocking, and steel tension ties.
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If you happen to have a well drilling company nearby, they might have some well casing they'd part with. You'll probably need a welder to attach some gate hinges.
Start exploring extravagant (nice) gate companies and look for those that provide details on foundations and footings!
You also might think about an alternative to that heavy gate.
I did a project like this once and we used a pressure treated 4 x 6 that we put 3 feet in the ground and used about 12 bags of concrete with about 2/3 of the concrete offset to create a cantilever weight. I went back to the customers house last year after 20 years and that post is still in perfect condition.
You should have a metals supplier in your area that would carry. a variety of square tubing. Metal tubing comes in outside size and wall thickness. In my opinion 4" square tubbing is extreme over kill. I just built a fence which used 2 1/2" galvanized tubbing set in concrete for a sleeve in the ground and 2" tubing for posts. You could easily get by with smaller posts with greater wall thickness. You probably don't want it too small due to the thickness of the gate. 2.5" tubing with 1/4 walls or 3" tubing with 3/16" walls would probably work just fine. If you come up with a plan that involves using a sleeve of a larger size, be aware that there is a weld inside of the tubing on one wall that needs to be accounted for when sizing the tubing. You should also thing about welding a rebar cage to your post where it is in the concrete.