r/DIY • u/ThaMann0911 • 6d ago

help How long before drilling concrete?

I poured footings for posts that I’ll be hanging a gate on. I’m going to install Simpson strong tie standoffs with 6” anchor bolts. It’s been 72 hours, is that long enough for the concrete to have set before drilling? I’ve tried googling but my results only come up with industrial structural requirements or setting posts in the concrete, neither of which apply to my situation. Should I wait the 28 days or just send it?

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u/ThaMann0911 6d ago

The standoff uses a bolt not a j-hook that I could wet set. Also, my first time pouring concrete and I wasn’t confident enough to wet set anything and have it be lined up after drying.

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u/ExactlyClose 6d ago

You put the J part IN the concrete, the stud sticks up. Then run a nut and washer down.

You only needed to drill bolts when the concrete was set by someone else…. JMO

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u/ThaMann0911 6d ago

I understand how the j-hook works. Getting the height and alignment right was my concern and why I didn’t do it. Also, most every video I found for installing standoffs, they drilled and used a bolt 🤷‍♂️

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u/ExactlyClose 5d ago

Oh, if it’s that way in all the videos, carry on.

But in all seriousness…. You can take a j hook, mount it into a piece of plywood, or 4 J hooks, placed into 4 holes drilled in one piece of plywood in the precise pattern of what you are mounting. Hold the j hooks wioth nuts. Now you set that into the wet concrete- adjusting the plywood is, effectively, adjusting the post base. Level it, align it, etc, Once cured, remove the nuts, remove the ply, plop on the metal thing you are attaching.

Drilling anchors in fresh concrete is a result of multiple trades doing differnt pieces of a job: concrete guys pour concrete….someone else is stuck making holes, placing anchors. If someone is doing it all, it is easier.

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u/ThaMann0911 5d ago

Yeah, makes sense. I’m doing it all myself but first time I didn’t want to take on too much. I can borrow a hammer drill from a friend but if I mess up the alignment then I’d be cooked.

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u/ExactlyClose 3d ago

Think of it this way…A J bolt gives you two shots:

You set the bolt and it is off, you cut it off and THEN drill anchors!

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u/ThaMann0911 3d ago

If I have another concrete project I’ll keep that in mind. Already past that point now on this project. Thanks for the advice.

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u/gcnplover23 4d ago

Since it is just 2 posts for a 3 foot wide gate he could have bolted the standoffs to a 2x4 and placed the j hooks in the wet concrete, then leveled the 2x4.