Is this a mold?

[Steve in PA]

I went to look at a possible repair today. I'm just not sure what I'm up against. I have never seen anything like this on a shower floor.

Homeowner says they don't have hard water. I saw a little standing water near the drain. I'm thinking there was no pre slope. These pictures aren't the best but they show what I am talking about. This stuff is real hard and pretty white and sharp at the top. ???

[Shaughnn]

Efflorescence. Is this an issolated bloom or is it throughout the shower pan? It looks like it's close to a wall? If so, is it a control wall (with valves)? A leak in the wall or a penetration that collects water from shower use could channel salts down behind the tile and collect at that point in the pan. A better idea of the bloom's location in relation to the rest of the fixtures would be helpful
Shaughnn

[Steve in PA]

it's issolated. the wall it is closest to is not the control wall. the shower head and valve are on the wall to the right. red line in the pic is close to where this bloom is.

[Shaughnn]

So, if I'm picturing this correctly, the shower blows onto the wall directly above the bloom? And it IS a thick-bed installation (floated)?
Shaughnn

[John Bridge]

I concur with Shaughnn. It's efflorescence, and as far as I know there is only one cure in this case (if it can be cured at all)

You need to replace the shower floor tile and the mortar bed. If there is no pre-slope you need to do a pan replacement.

You can't just make it go away. I have tried.

[Shaughnn]

John,
Couldn't a tile stone be used to smooth out the rough parts for the time being until the homeowner can afford to replace everything? I know that I've seen enough heartbroken customers when they're presented with the "it all must go" option to know that offering a more gentle short-term remedy helps the bitter pill go down.
Shaughnn

[John Bridge]

Yes, you can reduce it somewhat, but in my experience when it's gone on that long, the glaze of the tiles has been destroyed. The stuff actually gets into the clay beneath the glaze and pops it up.

I've never been a naysayer, but this stuff is murder.

[Shaughnn]

Oh, I deffinately agree John. But since this bloom is "jagged" and most people aren't prepared to drop a big chunk of change at the drop of a hat I was just suggesting a quick fix. I'm sure the glaze is shot.
Shaughnn

[rob 223]

WHat is the cause of efflorescence, and the way to avoid it? Can it happen just from having standing water?
Thanks

[Shaughnn]

It's caused by the migration of mineral salts. You will see it in masonry retaining walls where the soil behind the wall is high in fertilizers and drainage is inadequate. In this case, as I indicated earlier, the shower head may be blowing onto the wall. This added pressure drives just a bit more moisture into the substrate which then collects mineral salts from the mortar bed (if it is a mortar bed). These salts then migrate down the wall and are collecting at the point of the bloom, most likely because their normal path to the weep holes in the drain is obstructed. In any established mud pan, you can expect to see some ammount of effloescence seeping through the weep holes if you remove the drain cover and peek inside. I suspect that these weep holes are blocked and/or there is a depression at the site of the bloom which is causing mineral salts to accumulate and "burst forth in vibrant glory".
Shaughnn