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I've had a shelf come free from the wall on which it was anchored. The shelf is fairly deep (~2') and solid wood, so it's heavy, and it's meant to take some weight (think like a breakfast bar).

The two 90º triangle brackets supporting the shelf pulled the anchors and bolts right out of the brick wall when somebody leaned on it.

Now I have four ~3/4" holes in the brick from the previous anchors. The previous anchors look like this: enter image description here

They've left pretty smooth holes. So I now need to work out the best way to re-use those positions on the wall for new, more appropriate/stronger anchors. I could drill out new holes in the brackets to avoid the existing holes in the wall, but I'd rather not if possible.

Any suggestions would be appreciated!

Update: A photo of the actual hardware. They're 1/2" holes, according to the writing on the anchor.

enter image description here

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3 Answers 3

up vote 2 down vote accepted

The anchor you show is a lead anchor that is often used for masonry. However, as you see it failed. Lead is crushed into the walls of the hole by the screw or bolt holding it, but is prone to tearing under heavy load. The walls of the hole may also crumble under heavy pressure.

If the holes are truly 3/4, you can use an expansion fastener that is steel, such as this one. It is less prone to failure.

sleeve anchor

However, I would strongly urge that you increase the number of support brackets, or you will be facing the same type of situation you already have.

If the holes are larger or uneven or crumbly, drill new holes.

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Thanks, bib. I updated the question with a photo of the actual hardware. I'd thought of expansion bolts/fasteners.. they're what's used for rock climbing bolts and anchors in rock, after all. No need for an epoxy, in your opinion, if the holes are still 1/2" and in good shape? I'd probably go for a 5/8" fastener and bore out the hole a tad more if necessary, just to be safe. –  Gavin Oct 9 '13 at 15:53
    
I have not used epoxy, but understand its appeal. Be sure the hole is the size called for by the fastener, and I would try to increase the number of brackets and fasteners. –  bib Oct 9 '13 at 16:00

Simpson Strong-Tie has an epoxy system for permanently setting structural anchoring systems in cement. It's probably the strongest you will come across. The bolts need to go as deeply into the wall as possible for maximum surface area. One of your problems with this mounting is that steel is quite strong in shear but leverage increases pretty swiftly when they pull out.

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Yea, that's the problem I'm seeing - the bolts are being pulled pretty much directly from the wall with the leverage of the bracket. Is this what you're referring to? What sort of hardware would you use in the epoxy - another anchor, just a bolt? –  Gavin Oct 9 '13 at 15:56
    
The usual application is threaded rod, a fully threaded bolt will work, but not one just threaded at the end. I like epoxy better in brick than expansion anchors because they can fracture the brick. An uneven hole is actually beneficial with epoxy, but not expansion anchors (assuming the hole isn't flared outwards, which is bad no matter what) No matter what, you can't get good tension values in brick, so increasing the bracket count is a good idea. –  bcworkz Oct 9 '13 at 21:13
    
Hm, okay. I think I'm going to drill a new hole in both of the brackets to start and see how well set it feels. I could get my hands on a third bracket if it's still not right. Silly question, and the instructions would probably cover this, but you fill with epoxy and let it set before putting whatever bolt into it, right? –  Gavin Oct 11 '13 at 14:37

You can use anchor cement to fill the holes and then insert the anchors

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Thanks, Yurly, Fiasco above you had the same solution. What would you do with the epoxy-filled holes? Bolts straight into that? I'll almost definitely use longer bolts than were used originally, so the new hole will have to be deeper (see original picture, they're 1/2" lag anchors). –  Gavin Oct 9 '13 at 15:58

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