Marble Shower Entry

[clicata (Christopher Licata)]

I responded to a client that thought his marble shower entry area, at the glass door had mold in it. I inspected the marble, and it has copper colored stains either from the back out or the top down, all the way through the marble. It does not appear to be mold, it is dry and can not be wiped off. It is in the marble. It was white/Grey marble. Now it is spreading throughout the entire piece of marble. A copper color stain with black rings. I have photos, Let me know what you guys think.

[kbrittain (Kenneth Brittain)]

Adhesive bleeding through?

[sstanczyk (Stephen Stanczyk, WA License #221)]

Marble is very porous compared to other stone flooring materials. They will easily stain. This could have been from a potted plant sitting on the sill or hair products with colors added draining to that specific area. It will a stone specialist to determine cause and if it can be repaired or will need to be replaced.

[btoye (Bradley Toye, CMI)]

Wow, that’s a big stain. Marble is very porous and can bleed rust from underneath…could be leaking at the edge onto something like wire lath. You can’t even use thinset mortar on green marble due to bleeding…have to use epoxy.

[cwallace1 (Charles Wallace, OK License # 70001308)]

Looks like Rust to me coming from underneath but only way to verify would be for contractor to pull it up and determine.

[mpagozalski (Mike Pagozalski, CMI)]

@btoye

Wow, that’s a big stain. Marble is very porous and can bleed rust from underneath…could be leaking at the edge onto something like wire lath. You can’t even use thinset mortar on green marble due to bleeding…have to use epoxy.

that would be my guess as well

[fkrivsky (Frank J. Krivsky)]

could it possibly be rust from within?

White marble tile (especially Carrara marble) can contain small deposits of iron.

If these deposits are exposed to water, they can rust and leach through to the surface causing the yellow/brown stains.

Now, the marble would have to get somewhat saturated for this to happen. If water remains on the surface for hours it could absorb enough to rust the iron and then as the rusty water evaporates it is brought back to the surface.

Rust stains are a bit of a nightmare for marble cleaning. Can be tough to remove especially if old and/or deep.

The other, more common cause is water getting trapped underneath the tile (or slab in this case) due to voids or cracks in the grout… or otherwise poor installation.

I would do a man-made quarts overlay to repair the cosmetic issue vs pulling the door off and replacing it. Ceasar Stone sells a 1/2" thick stone and is pretty tough to stain.