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Plaster Walls and plugs

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  • May 13th, 2021 9:38 pm
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Deal Addict
Apr 26, 2003
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Plaster Walls and plugs

This issue is driving me nuts and I can't seem to find a good solution to this issue I'm having and covet the collective knowledge of this forum to help me out.

My house is built in 1970 and the walls are double brick construction, so there's no space behind the plaster walls. It's just plaster, a tiny gap and then concrete block and then the exterior brick.

Wall.jpg

I had our contractor who helped to redo the house install these Umbra curtain rods at the end of the project but they ended up using the screw in drywall anchors and over a few weeks, they literally just fell out of the wall and left gaping holes.

Curtain Rods.jpg
Curtain Clip.jpg
Clip.jpg
Hole1.jpg
Hole2.jpg

The drywall anchors left massive holes. The holes go deep through the plaster and a 3" drill bit goes straight in before it hits the layer of concrete block. I filled in the holes with exterior mortar joint thinking that it'd be hard enough to drill through so I could use 3 1/4" Tapcon screws to hit the concrete so there's something solid to mount into. These: https://www.homedepot.ca/product/tapcon-3-16-inch-x-3-1-4-inch-flat-head-phillips-drive-concrete-screw-with-bit-10-pack/1000540225 I have to use these screws because they fit through the clip and it keeps the structure of the umbra curtain rod intact.

Mortar Hole 1.jpg
Mortar Hole 2.jpg

So I cleaned it up, put drywall mud to cover the ugly mortar, painted it and drilled a pilot hole and was hoping the 3 1/4" tapcons would grab the concrete behind and all would be good. That did not work and now I'm super frustrated that the screws aren't grabbing into anything and the clip is loose.

If you have any other suggestions I'd be grateful.

Caveat: spring toggle bolts won't work because there's not enough space behind the plaster for them to pop open
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Mar 13, 2008
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You did everything right.
You filled the hole, but you need to fill it with concrete not mortar. You need to roughen the inside wall of the hole to allow for mechanical grip. Let it cure for a few days. Don't apply your dry wall putty just yet.
Once cured, drill a tap on into it and if it cured and bonded well it will give the bite the tspcon needs. Then there's the matter of load. Curtains are heavy, so get a deep tapcon, and hammer drill the pilot so it bites into the exterior brick part way. Now you have two places holding the tapcon to carry the weight.

Then try the curtain for a week. ..if it holds, then go back a drywall putty and make it look pretty.

Please let me know if this works
-ZdpZ... ;)
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Jan 19, 2011
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You state there is a gap between the plaster and the concrete block, but that is impossible, either the coarse plaster has been applied directly to the block, or furring strips (much like older lath and plaster / plaster and lath construction) will have been used.

If furring strips, they will be approximately two inches by a quarter inch laid flat, with about a quarter inch space between each to allow the coarse plaster to 'key' through the gaps and hold the plaster in place.

if furring strips, you should be able to mount anything by screwing it in with a regular wood screw, but be sure to drill a pilot hole though the plaster first to avoid having it break
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Deal Addict
Apr 26, 2003
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zdpz wrote: You did everything right.
You filled the hole, but you need to fill it with concrete not mortar. You need to roughen the inside wall of the hole to allow for mechanical grip. Let it cure for a few days. Don't apply your dry wall putty just yet.
Once cured, drill a tap on into it and if it cured and bonded well it will give the bite the tspcon needs. Then there's the matter of load. Curtains are heavy, so get a deep tapcon, and hammer drill the pilot so it bites into the exterior brick part way. Now you have two places holding the tapcon to carry the weight.

Then try the curtain for a week. ..if it holds, then go back a drywall putty and make it look pretty.

Please let me know if this works
The mortar was dried already and I drilled through it with a tapcon bit, but the tapcon didn't catch and it's loose right now and pulls right out. I wasn't thinking the mortar would hold it, but the concrete behind it.
Last edited by exrcoupe on May 11th, 2021 11:31 pm, edited 1 time in total.
Deal Addict
Apr 26, 2003
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fieldhousehandyman wrote: You state there is a gap between the plaster and the concrete block, but that is impossible, either the coarse plaster has been applied directly to the block, or furring strips (much like older lath and plaster / plaster and lath construction) will have been used.

If furring strips, they will be approximately two inches by a quarter inch laid flat, with about a quarter inch space between each to allow the coarse plaster to 'key' through the gaps and hold the plaster in place.

if furring strips, you should be able to mount anything by screwing it in with a regular wood screw, but be sure to drill a pilot hole though the plaster first to avoid having it break
It's not lath and plaster as you asked, but looking the pictures again, I think there might be a thin board behind the layer of plaster that was used to apply it to.
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exrcoupe wrote: The mortar was dried already and I drilled through it with a tapcon bit, but the tapcon didn't catch and it's loose right now and pulls right out. I wasn't thinking the mortar would hold it, but the concrete behind it.
Yes sir, mortar won't take the load, and the greatest downward force is at the head of the tapcon so this part needs to be the strongest. You need tightly packed concrete and the hole needs to be roughened on the inside, and break apart from deep inside so there's a T shaped cavity. This will allow the concrete to have the greatest surface area to bond Into and mass. Let it cure for atleast a week since it's indoors.

We use tapcons in concrete basements and concrete walls on the garage for decades so believe me, this will work. Make sure you mix the right amount of and size of gravel for this particular size...it shouldn't just be a sandmix with water.
-ZdpZ... ;)
Member
Feb 28, 2021
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Could you use a longer tapcon to grab the first layer of brick?
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Apr 26, 2003
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thebluegoat wrote: Could you use a longer tapcon to grab the first layer of brick?
Going to grab some 4" screws and see if that works. Curbside pickups suck.
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Mar 24, 2009
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KW
Shouldn’t you call the contractor back to install them properly?
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They will be coming back for punch list items that are still outstanding and this was one of them, but because of Covid numbers, we've held off for a while just so things calm down a bit. This isn't super urgent enough for them to come back for this only and not having curtains in the front living room is annoying since it's like living in a fish bowl at night, so I'm tackling this first.
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Nov 27, 2020
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My own similar experience has lead me to install all window coverings into the wooden window frames. All else fails eventually.
Deal Addict
Nov 17, 2004
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Get some 4 inch 1/4” tapcon and use a 5/32 drill bit as instructed for 3/16” tapcons.

Brick and concrete blocks tend to crumble a bit when drilling (vs solid concrete pours), so the above is the fool-proof way of making sure that tapcon will bite and hold properly every time.

I also have a double-brick house and I go straight to long tapcons to mount things to the exterior walls and use the method above, otherwise about 25% of my tapcons require a new hole when I try to use 3/16 tapcons or I have to use a 1/4” in the hole anyway.
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lamin wrote: What you can do is get some decorative wooden blocks and pl them to the wall and put one long tapcon in the middle of rod holder. Also, is that wood behind the plaster?

https://www.homedepot.ca/en/home/catego ... lding.html

1001541129 look up this sku
If longer tapcons don't work, I think I might have to go this route.
CensoredByRFD wrote: Get some 4 inch 1/4” tapcon and use a 5/32 drill bit as instructed for 3/16” tapcons.

Brick and concrete blocks tend to crumble a bit when drilling (vs solid concrete pours), so the above is the fool-proof way of making sure that tapcon will bite and hold properly every time.

I also have a double-brick house and I go straight to long tapcons to mount things to the exterior walls and use the method above, otherwise about 25% of my tapcons require a new hole when I try to use 3/16 tapcons or I have to use a 1/4” in the hole anyway.
Yeah, put in an order for 4" Cobratap screws from Rona since they don't have anything longer than 3 1/4" in Tapcon at HomeDepot. I remeasured the hole with the bit and the 4" screws should give enough bite into the concrete to grab it well once and for all.
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Jan 21, 2011
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exrcoupe wrote: If longer tapcons don't work, I think I might have to go this route.

Better to go this route now, deal with it once, the wood block will always be there so you don’t have to go through this again unless you change your window treatment drastically. You don’t have to you pl, silicone works just as well.

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