Is this Blue Grout or is it something else?

[JohnfrWhipple]

I have to laugh sometimes at the other forum. It really is quite sad when such a simple question gets such a bad answer. And even sadder that no pro - step up to offer up another answer.

This lady writes this:

"...Okay, here is my story. A few months ago we installed a new shower. On the floor we used 1x1 Pineapple Onyx and a light tan grout. Under the tile is the thinset, mortar, black rubber thingy for the liner and then mortar. Slope is perfect. Oh yeah and the tile and grout were sealed using 511.

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Pretty much right away I noticed that the tiles around the drain were discolored (wet look). My husband told me that it just takes longer for those tiles to dry because they are by the drain. I bought the excuse and ignored it but it kept bothering me so we stopped using the shower to give that area time to dry. 5 weeks went by and the discoloration was still there. Obviously my husband was wrong.

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I thought maybe it was the weep holes but we protected the weep holes with pebbles. Anyway, today I decided to grind out some of the grout and see what was going on. Under the surface of the discolored grout was blue grout. No blue grout was used, ever.
My question (I have a few)
what would turn the grout blue under the surface?
Is this what caused the tile to appear darker than others?
Is there a way to test the weep holes without removing the tile?
What the heck is going on??

Hopefully my pictures will come through.

Any help will be greatly appreciated...." Source

So the Questions are

1. What would turn the grout blue under the surface?
2. Is this what caused the tile to appear darker than others?
3. Is there a way to test the weep holes without removing the tile?
4. What the heck is going on??

I would answer like this

1. Most likely the tool you used to grind the grout away.
2. I think not
3. Not really - If the weep holes are working you will see dripping down the inside of the drain
4. Pretty sure the weep holes are plugged, or the bottom channels are not being used

One fellow on the JB forum suggested that it might be thin-set under the onyx tile. But for that light coloured stone a white setting material should have been used. The powder and tool marks show me that the cause is from what I think is Metal transfer. A cheap metal rubbing off on the grout.

There is not so much you can do in a job like this. Before any drastic measures are taken I would let the shower sit one session. Let any further shrinkage of mortar and thin-set perhaps help things out with some hair line cracking.

A more drastic approach would be to try and add a few weep holes in the side of the drain's ajustable collar.

A rough approach with huge downside risk would be a sharp blow to the drain assembly.

With care the old drain could be removed and you could get to the bottom of the clamping collar and see.

A year back the NTCA published an email report that was done by some tile guy in California. He was saying that all his samples that he made got plugged and that weep holes that where working at the start stopped later in the test.

I have followed up with bart from the NTCA for over a year and have yet to hear anything else about it.

Next time use one of these.

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Above you can see a lot going on. If you look just right you can see some clear shiny plastic. That is the Noble Company Positive Weep Hole Protector. The blue membrane over top is NobleSeal CIS - custom ACO Flashing I made for this linear drain install. The waffled material allows water flow under the shower mortar bed to the drain.

The key weep holes are the lower channels. Here is a diagram showing the various peepholes on a a typical clamping drain.
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The drain shown is a Sioux Chief. Watch out for the new models. I not sold yet on the bolts. I think they are not the same quality as the older ones.