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I've been trying to remove floating shelves fixed onto a masonry wall with no visible screws. After cutting into it with a saw, I've found it is held up with the following fixing:

Unknown fixing

The exposed part of it was screwed into the wood of the shelf, and it appears the part in the wall has perhaps been set with some sort of mortar.

What type of fixing is this, and how do I remove it from the wall?

Also, I still have a bunch of shelves still in the wall that I need to take down. So far I've just been going at it with my reciprocating saw, as both my hammer drill and oscillating multitool seemed to have no impact on them. However, even with the saw, I've broken a few blades so far (possibly due to the awkward angles involved).

Is there something better I should be using to remove shelves fixed in this manner?

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    It looks like a lag bolt, but with the pointy end shorten by grinding at an angle. Don't know how well it would screw in like that.
    – crip659
    Oct 29, 2022 at 17:52
  • Experiment: Try to use a hammer drill to ream out a larger hole around the bolt in the wall, full depth of the bolt, then a sledge hammer to loosen the bolt in the now-weakened hole in the wall. If that's not too difficult it leaves the bolts in the shelves, you don't have to cut the shelves or the bolts.
    – jay613
    Oct 29, 2022 at 18:24
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    Given the shank to threads relationship, I think you might have the (large) head of the lag set in mortar. Try hitting it with a big sledgehammer. Then patch the big hole. Oct 29, 2022 at 18:24

3 Answers 3

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Chemical anchor

From your photo it's fairly likely that this is a chemical anchor: a bolt that is basically glued into the wall using a really strong polyester resin (you can see the slightly differently coloured material surrounding the bolt in the hole). These are much stronger than anything purely mechanical, so they are typically used where mechanical (expansion/toggle) anchors won't do. Once the resin cures, there's nothing in the world that will remove the bolt; the wall will probably give way before the resin does.

I suspect the author screwed the bolts into the shelves first, injected the resin into the holes in the wall and then just pushed the bolts into the holes and waited a little for the resin to set.

Given all this, cutting the bolts flush with the wall is probably your only option. Because they are typically made from really tough steel (to match the strength of the resin), you will probably need brute force in the shape of an angle grinder (a plasma cutter or oxyacetylene torch would do, too).

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My guess is it'e some type of hanger bolt, with an expansion shield embedded in the wall similar to the one shown below from Harfington,https://www.harfington.com/products/p-1039484. I'd think about getting a rotary tool, Dremel, with a cutoff wheel and just cut them off. An angle grinder would work too. Try grabbing the protruding screw with some vise grips and see if you can turn it.

enter image description here

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  • It is expected that your answer provide attribution to where / whom the picture came from. Please update your answer to comply with SE policies.
    – Michael Karas
    Oct 30, 2022 at 18:05
  • @MichaelKaras Done
    – JACK
    Oct 30, 2022 at 19:25
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If you like to cut them all flush with the wall, the simplest and quickest way is to use a grinder with a cut off blade. You will cut all of them without struggle and fast. Images courtesy of Harbor Freight.

I would think there is no need to remove them from the wall.

Angle grinder Die grinder

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  • It is expected that your answer provide attribution to where / whom the picture came from. Please update your answer to comply with SE policies.
    – Michael Karas
    Oct 30, 2022 at 18:05

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