# fastening to brittle block



## madchad (Aug 15, 2007)

I am installing a 3/4" raceway on a wall above ceiling. The wall is block laminated with 1/2" sheetrock. The block is also old and brittle when drilled. I attempted to use plastic anchors but the anchor has to be driven through the rock flush with the block. This is hard because of the limited working space. Is there a tapcon that may work, or another fastener?


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## 480sparky (Feb 1, 2009)

Toggle bolts.


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## dave_dj1 (Mar 16, 2010)

tapcons


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## Big Chris (Dec 3, 2006)

Can't recall the official name of them but basically a 1/4 " wedge/ sleeve anchor. I know Redhead makes them, I'm sure others do as well. That's what I'd try.


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## 480sparky (Feb 1, 2009)

Big Chris said:


> Can't recall the official name of them but basically a 1/4 " wedge/ sleeve anchor. I know Redhead makes them, I'm sure others do as well. That's what I'd try.



Sleeve anchor?


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## Warren (Feb 19, 2005)

Hilti makes anchors that use epoxy also


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## Inner10 (Mar 12, 2009)

I use hilti quikcons but I shoot a bit of HIT adhesive or polyurethane into the hole.


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## protechplumbing (Oct 10, 2008)

1/4" x 2" tap-cons work wonders in that situation.


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## griz (Nov 26, 2009)

My concern is the brittle block you describe. With any kind of penetrating fastener you have no idea if it has a solid bite & will hold. Are you dealing with any kind of specifications to attach?

If you are talking about Panduit or Wiremold type products & only 3/4" why don't you look into the 3M Commercial Bonding Tapes and attach to the sheetrock.


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## DuMass (Feb 6, 2008)

I would take a look around and see what they used to secure that drywall to the block. It would be interesting to know being that the block is in as bad a shape as you say. 
Seems like maybe a 1-1/2" long 3/16" or 1/4" Tapcon should work.

I have several different sizes of Rawl nail in fasteners I sometimes use. Some are just simple drive pins that you hit with a hammer and pin driver to set. No hole needed. 
The other two types I have are either a plastic or metal expanding nail-in anchor that you first drill a 3/16" or 1/4"diameter hole and then tap them in with a hammer. These would probably work even with the 1/2" drywall on top, if you get them in the right size/length.

Powers and others also make conduit straps with nails that you set with a [PAT] power driver. A light power load along with a depth control disk might work.


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## SC sawdaddy (Oct 15, 2008)

For a 3/4" track installation I'd favor a tap-con over a bigger fastener like a Red head. Seems like overkill to me.


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## John Valdes (Apr 14, 2010)

I also ask "how is the drywall attached to the block" Laminated you say? Glued?
I am also in agreement that Tapcons are your best bet if the drywall is glued or laminated to the block. If its attached via furring strips, use them and some wood screws.


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## svh19044 (Oct 22, 2007)

Without knowing how brittle the block is, if I were using tapcons, I'd throw in some glue/epoxy for added security.

If it's hollow block, good toggle bolts are hard to bear.

If it's solid block, the best option is probably going to be a good lead machine screw anchor.

No matter which anchor, your best bet is to use a GOOD hammer drill. If you are using a crappy hammer drill, you aren't going to get good results no matter what you do.


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## Big Chris (Dec 3, 2006)

480sparky said:


> Sleeve anchor?


Yes, that is what I was thinking of.


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## mdshunk (Mar 13, 2005)

It might be too late for my two cents, but for just some 3/4 conduit, I'd recommend you use some Zamac's for the fastening problem you describe. Fast, secure, and only as strong as it needs to be.


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