I am trying to secure a floating mantle shelf over a brick fireplace wall.

I used 2 3/4" 3/16 tapcon screws to secure the strip of wood to a brick wall but the wood strip did not hold securely

The tapcon 3/16" screws called for a 5/32 mortar bit hole which I used, but when I drilled the tapcon screws into the mortar they felt loose, as if the hole was too big.

Any guesses as to what might have gone wrong? Any suggestions as what type of fasteners would work better in securing the wood strip to the brick wall?

  • 1
    Are you sure it's actually a brick wall and not a facade?
    – Mazura
    Feb 9, 2018 at 22:36
  • The bit is only the right size if you held the drill absolutely perfectly perpendicular and drilled a perfect straight hole. I'd be willing to bet that if you put the bit back in the hole (without the drill) it's going to be a little sloppy. Oct 25, 2018 at 19:02

3 Answers 3


Tapconing into a mortar joint is to be avoided.

See the discussion here.

And the one here about how 3/16" are garbage. Use 1/4".

If the Tapcon goes into a mortar joint it's pull out strength will depend on the compressive PSI of the mortar and the depth of the mortar joint in combination with the length & diameter of the Tapcon.


  • 1
    Meh, depends on the use, but I've had a lot of luck with the 3/16". Drilling into the correct material is the main issue.
    – JPhi1618
    Feb 9, 2018 at 18:40
  • 1
    They do work, sure. But you have to be really careful about over reaming the hole when using them (see the second link), especially when going into mortar. 1/4" are much more forgiving. And I'd bet that one would fit perfectly now that it's a striped hole from a 3/16".
    – Mazura
    Feb 9, 2018 at 18:54
  • I agree that mortar is not the best place to place a Tapcon anchor especially with a high load value like a shelf. But I have used quite a few 3/16 with no problem. Making sure to drill straight and do not over torque the screws are just as important as the material expected to hold the screw.
    – Ed Beal
    Feb 9, 2018 at 21:42

For something as substantial as a mantle, I would not use simple Tapcons. Tapcons are great for simple fasteners, but aren't that great for something like this.

I would highly suggest installing a sleeve anchor of some sort. You'll get better traction on the brick/mortar and it will penetrate the surface easily.

If you're absolutely set on using Tapcons, I find a toothpick shoved in the hole can sometimes give it the missing bite (but I've only used it on simpler things like a bird feeder). Use with caution on a mantle.


had the same issue with the Tapcons not gripping......find out after multiple trips to the hardware store and talking to some seasoned contractors to use a bit smaller by a size or 2 then the one they recommend. Pretty easy solution but you figure the maker of the product is giving the right info but not always.

  • 2
    This is appropriate only if you're installing in mortar or other soft material. For concrete, the screws will snap off if you do that. The manufacturer knows of what they speak, which is that you shouldn't use them in mortar.
    – isherwood
    Oct 25, 2018 at 17:52

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