I just installed a pedestal sink against an exterior wall.



The exterior wall is of concrete blocks. Unfortunately, the previous owner laid new tiles over existing tiles, causing the concrete block to be about 2-1/2" behind the finished tiles. In between are two layers of tiles, cement board, 1X wood furrings etc...I wanted to get all the way to the concrete blocks, so I decided to use 1/4" Tapcon screws and I drilled two 3/16" holes where the sink mounting holes are.

Because of how far back the block is, I calculated say 1" of minimum block penetration, plus 2.5" of various layers of tiles, plus about 3/4" of the sink ceramic, plus a rubber and metal washer, that's about 4-1/4" so I will need screws at least this long.

It turns out Tapcon screws come in 4" and 5" (nothing longer than 5". However, I couldn't use the 5" version because the recessed "notches" in front of the holes under the sink is like 3.5" long, I can't put the sink down on the pedestal and insert the 5" screws, there is not enough room in that space under the sink to fit a 5" screw EVEN if I try to feed some of it before I sit the sink on the pedestal. I end up using 4" screws which barely fit that depth of space in front of the mounting holes.

As I tightened on the 4" screws they didn't bite real hard on the block as I had hope. It is "spinning" a little.



I put silicone caulk between the sink and wall, and more silicone caulk between the pedestal base and floor. The pedestal base is secured with one Tapcon screw to the floor and that is very secure.

I am trying to figure out if the Tapcon screws not mounted securely to the wall will be an issue...?

I can't drill the holes somewhere else.

I can't use 5" screws. They won't fit into the notch under the sink.

I can't use toggle bolts because I do not feel or see any "air space" behind the two holes.

The only thing I can think of to do may be to back out the Tapcon screws, and inject some epoxy into the 3/16" holes, then put the Tapcon screws back.

or leave it alone?

Thoughts?



Edited 1 times.

Epoxy and threaded rods/nuts.

the time to have solved this was before the sink was installed not after..
3/8 lag screws may do the trick.

I couldn't find a 1/4" hanger bolt that is that long. I probably could have gone with a bigger diameter.

The problem I see now is I should have epoxied in two threaded rods into the wall beforehand. I was hoping the Tapcon screws will get a good bite but they didn't. I think it has almost an inch of penetration into the block but didn't bite hard. I don't even know if I can back it off now because the ceramic notch under the sink is only about 3.5" deep and the screw head will hit the back of that notch before the whole screw is backed out.

I guess one other thing I could do is to back out the Tapcon screws half way, use an angle grinder to cut the shaft off, then continue to back them out all the way. Then go to the outside of the same wall, and break open the far side of the concrete block, feed two threaded rods from the back side through the front of the block, through the tiles and then use nuts on both sides. Just not sure if it's worth the effort.

Is it in a rental ? They'll tear it loose if it can be tore loose. If it's in your personal home I'd leave it be.

Its a rental. So it may take some abuse. I have to keep thinking.

next time use these.. install them BEFORE..

packy I used these hanger bolts previously for pedestal sinks and they worked well. The only thing is I thought they are for attaching to wood. Last time was an interior wall and I mounted a 2X4 between the studs and then attached the hanger bolts to the wood framing, with the bolt end sticking out about 1.5" from the finished tile surface, enough for the thickness of the ceramic, a rubber washer, a metal washer and a nut.

In this case it is an exterior wall with concrete blocks, and the last owner tiled over tiles. So I have two layers of tiles, plus cement board, and furring, building up to a total of 2.5" between finished wall surface and the block face. Added in the thickness of the ceramic with 1" of penetration to the blocks, I used the longest 1/4" Tapcon I can find which was 4". I couldn't find hanger bolts for masonry attachments.

I also thought about using larger diameter screws like 5/16" or even 3/8", problem is the two ceramic mounting holes are not that much bigger than 1/4". I was really concerned with a 3/8" bolt there is no wiggle room at all for the attachment.

sum, i've never had much luck simply bolting the sink to a wall using a one step process.
i always use the two step. insert the lag screw to the proper depth and then nut and washer to tighten sink.

You could sketch the outline of the basin on the tile, remove the sink, cut an opening in the tile that will be hid by the basin and tapcon a 2" X 4" to the block wall. You could add a piece of plywood to make the block sit flush with the tile. A diamond blade on a handheld grinder cuts tile surprisingly well.