You very likely have a waterproofing failure behind that tile. Do you have pictures of the in progress construction?

No , we haven't done anything to it yet. We were trying to figure out what to put on the floor first then we were going to proceed

I meant the original construction. That is where your issues originate. It's likely to be a tearout in that shower.

The guy who came in to see the problem said that water seeping through is a common problem with small tile? hence the reason why we were looking for a different floor?

every problem floor might have small tiles because every shower like that has small tiles. showers without problems have small tiles too. its not the tiles.

The guy that came in can be ruled out as a hack. You will know when your talking to a real tile pro.

They will look at your shower and tell you a few things based on their experience and tile knowledge. Heres a few things youll want to be looking for.

A. Tile size matters NOT when dealing with a mortar bed pan .

B. They will educate you on the type pan you have based on the"drain strainer" being of the clamping drain type.

C. They will all baulk at touching the job without telling you its possible the entire thing will need to be replaced the second we start opening it up depending on what they find.

D. 6 yr old shower works fine for 4 yrs and all of a sudden 2 yrs after that you are panicked about stains that have been brewing.could simply be body oils or improper cleaning.

Few tech notes :

If it were a shower pan grading issue where water is pooling under the tile in the mud bed it would have been happening day 1 and by now a festering mildewey mess.

If it is clogged weep holes the staining or water buildup would have started at the drain and worked its way outward

in mud bed showers weep holes can get blocked up and the best way to check is to simply use duct tape on the drain strainer ( very carefully dry and clean the strainer then cover it perfectly with duct tape and seal it up) Then simply fill your shower pan to the top of curb and let it drain. You will check 3 things A. weep holes functioning. B. If theres a bigger leak anywhere it will rear its head. C. When its over you will see exactly how your pan floor dries out and where the moisture remains after a few days.

Thats the first and best way to test it yourself now while continuing to look for and find a real tile professional to help you make a smart decision.

The issue is not the mosaic size; they could have been 2x2, 1x1 or the 5/8 x 5/8. There is water that is keeping the area wet and that's the issue. I suggest you talk to someone else, changing the mosaic size will not fix the problem as the current person is telling you.

Forgive my curiosity, but why is there a tub faucet in the shower?

We do not believe the problem to be the tile. It could have been pitched wrong or the seal underneath may not have been done properly. We suggest you tare the bottom to expose the floor. Has to be resealed and re-tiled. We suggest using tile in the shades already used. Try a porcelain tile as it is more resistant to staining. If the mosaic you are using has marble it may well be stained marble due to water being left there for too long and even the products you use can stain it. Marble is like a little sponge susceptible to staining.

WOW!!! Ok, so this is a BIG eye opener....I cannot thank you all enough for your input. It looks like we won't be jumping just yet to purchasing a new tile for the floor. After a very long discussion with my husband, it looks like we'll be getting a new person to come in and have a look.

I've also now had a change of heart and am thinking about replacing ALL the mosaic tile with a solid colour but keeping the dark tile. But that's for a different forum :)

@Mike re: the faucet in the shower....No real reason, it was just a preference we had.

Thank you all for your excellent input!

Totally speculating here, but the tile floor and grout might not hold up to the force of the water coming out of that faucet. Falling water from a shower head at 2 gallons per minute is what tile and grout is designed for, not 10 gallons per minute out of a faucet. I'm not a pro, just an engineer.

@Mike I understand what you mean, however, if that were the case, why wouldn't the spot be right under the spout rather than where it currently is? We don't use the spout very often anyway.

Tub spout has zero to do with the issue. The shower pan was not built properly, or was waterproofed incorrectly.

Any changes here mean gutting it all and redoing it all. Correctly this time.

As someone who is preparing to embark on two shower renovations, this has been an interesting read for me. Live_wire_oak, you mentioned pictures of in-progress construction. Are these typically provided by the contractor, or should the homeowners plan on taking those? I am assuming these would serve as proof of all step completed correctly (or not, as the case may be).

Everything.

In progress photos should be taken by the homeowner. Yes, a good contractor can take them as well, to serve as documentation of proper installation. Too many contractors simply do not do shower installs correctly at all. Either they botch the framing, botch the pre-slope, botch the waterproofing, or botch the tile installation. Or you get the quadfecta of all four incorrectly done.

Only the last step, the tile work, is visible enough to cause concern to a homeowner at the end. But, much like an iceberg, that hidden 3/4 of the project is more important than the visible 1/4. y the time you get to the decorative covering over the waterproofing, it's usually too late to do anything about the 3/4 without going back to step one.

Please get a real professional tile contractor in there. The size of the tile is absolutely not an issue (and mosaics are actually often preferred for a shower floor for multiple reasons).

adding to LWO

which is why you the homeowners must educate yourself on shower pan flood testing. How its done, how to measure and monitor, where to set the test plug for various types of builds/drains and how to confirm it drains properly.

Dont simply trust the contractor or inspector, but watch it yourself and be present. this is the second most important step second only to the actual hiring /selecting process.

Thanks so much LWO and thatsmuchbetter. Very educational...