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An impaired driver jumped my curb and ripped my square mail post out of the sidewalk concrete that it was anchored into. The bolts were all ripped out of the concrete. Bolts went through the metal plate into concrete, so when the post and anchor went, so did the bolts. I think a couple bolt grippers may still be in there.

I can get the same metal post anchor replacement so the holes will align and fit if I clean them out and work them a bit. All surrounding concrete damage is from the incident.

Is some repair going to hold long-term, like some concrete "caulk" and using the same holes? Or is it an eventual fatal wound, such as the holes will get bigger and start cracking around them?

Since water has gotten into them, will that cause any structural problems? Or will it eventually require the whole concrete sidewalk square (~3'x3') to be replaced, re-poured completely, to get it back to the condition it was in before?

Obviously cost is not a concern, but I need to know if a replacement is justified. Will a repair be good enough or a pad replacement is better/best?

Concrete damage from mail post anchor being ripped out by DUI driver.

Also want to clarify the sidewalk is slightly damaged. The surface streaks and has chips around it. If I drill new hole offset from old, will the old holes start to crack the concrete around them?

This isn't a legal forum but it is pertinent to know the driver had no insurance and he is in jail for the hit and run. He's being prosecuted by the city and I can get restitution from him. I won't have to sue in small claims. The point being, he'll be the one eventually reimbursing, but I have to justify a repour or if a repair is reasonable enough. My home insurance has a $500 deductible and will raise my rate so that's a no-go.

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    None of that stuff about the driver is relevant. Whether you have to pay for repairs or not isn't our concern. We don't provide opinions, and your budget and aesthetic standards are a matter of your opinion. You can ask about the repair without any of that distracting from that issue.
    – isherwood
    Commented Apr 9, 2021 at 20:42
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    It sounds like what you really want to know is whether the holes weaken the slab. I've edited your title to that. I'm not a moderator, but the community does most of the editing here, and we want your post to stay on topic so it isn't closed and so we can help. You can't ask us to decide which outcome is best. That's a subjective decision.
    – isherwood
    Commented Apr 9, 2021 at 20:48
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    @isherwood of course budget is on topic here. We regularly have answers give options for a range of budgets, from a DIY bodge that’ll last to hiring an expert to do a professional replacement. Recently there was one about saving money running electrical cables to a sub panel! Budget is not a matter of opinion, it’s fundamental to the entire topic of home improvement!
    – Tim
    Commented Apr 10, 2021 at 11:28
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    Yes, the cost of a project is relevant. Who pays for it is not. At that point it's a matter of personal prerogative whether a project goes forward, not an internet poll.
    – isherwood
    Commented Apr 10, 2021 at 21:07
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    Water in the holes won't be much of a problem (presumably the concrete gets wet when when it rains with no issues) but a water-filled hole which freezes in winter is guaranteed to cause cracks. The cracks will grow on every freeze-thaw cycle until you have a heap of rubble, not a sidewalk.
    – alephzero
    Commented Apr 11, 2021 at 18:48

7 Answers 7

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The concrete looks intact enough for re-use, I can't see if the anchor bolts are good or not, if they can't be reused getting old anchors out of concrete can be tricky: you might have to move your letter box one inch to the side so that new anchors can be drilled into virgin concrete.

If you do move it don't leave the old anchors protruding they are a trip hazard, if the can't be pulled out use an angle grinder to cut them and grind them flush.

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    I'd go 2-3 inches. One leaves too much chance of blowout into the existing holes.
    – isherwood
    Commented Apr 9, 2021 at 14:04
  • I should have taken an angle picture. No bolts are sticking up for trip hazard. They were ripped out.
    – Stay-at-home-dad
    Commented Apr 10, 2021 at 3:03
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    If there are holes where the anchors used to be, then (if they can't be re-used and frost is a possibility) they really should be filled and made waterproof: water will produce freeze-thaw cracking in the concrete.
    – Andrew Leach
    Commented Apr 10, 2021 at 8:45
  • What a shame we have such immoderate moderators! Despite their curious doubts, it should be obvious the life will be reduced, but by how much depends on too many factors… what size slab; which concrete mix; how many holes; what size holes… Despite the mods' obstructive timidity If you're truly worried, why not seek a trusted contractors' view?
    – Robbie Goodwin
    Commented Apr 27, 2021 at 22:58
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If you wanted to keep the post centered in it's current location, you could rotate the post 45 degrees and re-drill in place. You might not even need to do anything to the old bolts, as it's unlikely to be a tripping hazard so close to the post. You'd probably have to add a plywood mount at the top to rotate the mailbox back to perpendicular to the street, but it's not like it needs to bear a lot of weight.

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    I'd still try to get the anchors out, or grind them down far enough to cover them with some Quikrete or similar product. Concrete cancer could set in if those bolts are left to rust. The coating they get to prevent rusting doesn't cover the broken end. remedial.com.au/structural-repairs/concrete-cancer
    – computercarguy
    Commented Apr 9, 2021 at 15:56
  • I should have taken an angle picture. No bolts are sticking up for trip hazard. They were ripped out. If I redrilled close to it, the old holes will fill with snow and water and gunk. Would that cause them to crack sooner than later?
    – Stay-at-home-dad
    Commented Apr 10, 2021 at 3:05
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    @KirkHings if they fill with water, and you live in a climate which often switches from above to below 0°C (typically as part of the day night cycle), then yes.
    – Tim
    Commented Apr 10, 2021 at 11:30
  • @computercarguy That would certainly be best. If you ground them down, then smoothed out the whole surface, there would be no trace of the incident at all and it should be nearly good as new.
    – Eric Hauenstein
    Commented Apr 12, 2021 at 13:41
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One thing that might work well is to get some hard rapid-set mortar (they make them in smaller packages for patch jobs like this). The old bolts can be drilled out of their holes (use a metal-drilling the diameter of the shaft), then you can get a new mailbox and concrete the holes before adding new bolts.

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Inspect the anchors a little more closely. If they're the drive-in wedge type similar to the RED HEAD brand shown here (photo credit to Grainger), and if the installation hole was drilled clear through the concrete, then you may be able to simply drive them down into the soil below with the help of a hammer and dowel (a piece of rebar, a long bolt, etc). That would clear the way for new anchors to be installed in the same holes, with or without re-drilling.

wedge type concrete anchor

If the holes aren't in suitable condition for re-use as-is there are epoxy-based concrete anchor systems as well.

If all else fails: a 3 foot square patch of concrete is not all that big. It could be broken out and completely replaced, giving you freedom to mount the new mailbox how and where you wish.

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In my opinion it's easiest to just demo out the concrete patch and repour and set new anchor bolts. Least labor, best look, best structure. You could even consider adding some colorant to the new cement for a new look.

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    Easiest to remove and replace a concrete slab? I fail to follow your reasoning.
    – isherwood
    Commented Apr 9, 2021 at 20:37
  • It's only 3'x3'. Just a few hits with a 12-lb sledge will break it up into small enough pieces to easily dispose of. 1 10'x2"x4" plus 8 stakes to make a new form, Make paper template for the bolt placement, 1 bag of concrete and a 5-gallon bucket to mix new concrete, pour it into the form and float with a trowel or length of board. Use the template to push the bolts into the concrete, let cure, and reattach the mailbox base. Easy.
    – Arluin
    Commented Apr 10, 2021 at 0:26
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    are you confusing feet and inches? 3 foot a side is 9 square foot, that's about 0.1 cubic metres, or 10 bags of premix.
    – Criggie
    Commented Apr 10, 2021 at 13:28
  • That's half a day's work if all goes well, plus expense and disposal. Re-mounting to the existing slab might take an hour.
    – isherwood
    Commented Apr 10, 2021 at 21:05
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    You must have fairly weak concrete where you live. 6-8" slabs that are common here would take many extremely hard hits with a sledge to demolish and equipment rental is fairly cheap. It would make more sense to cut and chip. Getting bolt mountings properly set in concrete is not as easy as you describe and is better done with the bolts pre bolted to a wood template so a vibrator can be used to ensure good contact on the inset. Patching concrete and drilling holes is much easier.
    – K H
    Commented Apr 11, 2021 at 9:41
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I'm not sure if you changed your picture, but it appears there are no existing bolts or studs to worry about. If that's the case, one option is to clean the existing holes, then use the same size hammer drill to deepen the holes so you have a good 3-4" of good clean hole. Then use anchoring epoxy to anchor fresh all thread rod in the holes. Once you clean the holes and have the rods in place in the epoxy, you can bolt them to a pre-drilled board to make sure they stay straight and in the correct pattern until the epoxy cures. Once the epoxy has cured, remove the placement jig, patch the concrete chips and re - mount the mailbox.

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Is it possible to hammer the bolts out on the backside of the concrete plate ? by use of a sledge hammer. The you can just use new bolts in the same holes - maybe you have to use some 2-comp epoxy. If not then drill the top 2 inches away - starting with 6 mm and then drill again with diameter like the. It will cost you a drill or two (metal and concrete around) Fill holes Make new holes 2 inch away from the old ones

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