it means he doesn't know grout. Have you asked him how many years experience he has? Just to double-check something here: is the membrane (waterproofing) lying flat under the tiles? Very flat? Very level? Totally horizontal? What do you see? What answer does he give when you ask him about this?

He specializes in tiling (he says), but his website has a lot of bathrooms and kitchens on it which he has tiled. He's taking up the tile in the shower now, so I haven't been able to see the membrane underneath and didn't know to ask. I'll check.

We bought it ourselves when we bought the tile from the tile supplier- Emser Tile. I'll check the brand, the bag should be in my garage.

Polyblend Sanded Grout- Min grout lines 1/8", Max 1/2". Bought from the tile company- Emser.

I also ran into a problem with this grout. Had 2 different tile installers use the same grout within 1 month of each other, taking grout from the color grout -Custom Building Products Polyblend Sanded grout.

The first guy used a "blender" to mix his and the second guy just mix it with his trowel. The first turned out perfect. The second was "blotchy" with uneven color - some tan and some brown! The second regrouted using a new bag of grout - same problem. What could be going wrong? Is it the grout product? Is it the mixing method?

They even went to the mfg rep who said there was nothing wrong with the grout. Help!

From what I saw when he grouted the shower originally he mixed it with a trowel. And, yes, it is slightly darker in some spots. Really, I do have confidence he knows what he's doing. He does a lot of bathrooms and is meticulous in all his work. This one area in the center of the shower floor is the only problem we have had and this is a complete renovation including all new pipes and connections for a new tub and vastly expanded shower area. (House was built in the mid-80s in boomtown Atlanta, so everything was done substandard with building inspectors looking the other way- such as no flashing anywhere, pipes installed incorrectly and on and on.)

I've only had one problem with Custom's Polyblend Unsanded Grout over the years, it was probably back in '96. I called their Tech Support, they admitted to a bad batch, they threw several hundred dollars my way, and despite me begging them not to, they UPS'd me several bags of grout. Hey, I'm all for free product, but it would have been a lot easier for them and me had they just sent me a coupon or an extra $30 or something.

I show Tech Support at 800-282-8786. Have the bag info handy, the rough date of purchase, where it was bought, the bag might even have a lot number on it. Give them the time between installation and the first time water hit it. Have a few photos handy, you might be able to email them to the tech guy while you're speaking with him. Tell them if it was mixed with water, or water and an admix, or admix? Was it sealed, etc.

I do thoroughly dry mix the contents of the bag before adding water, then thoroughly mix again. I've mixed more than my share by hand with a margin trowel, and mixed more than one bag at a time with a paddle.

A problem with grout can be undermixing. Mix it properly and grout hits that magic spot, it handles beautifully. Some guys undermix if mixing by hand. Some use a paddle on too high a drill speed and can entrain air into the grout. Some add too much water so it doesn't set properly, or use too much water in cleanup which can wash pigment away, creating blotchy areas of mixed coloration.

There are a lot of ways to screw up grout.

Do report back, I'm interested in any troubleshooting they do.

I don't really trust the HD grouts. The "Polyblend" has bitten me in the butt many times. Colour is inconsistant and has "blotched" on many occations. Pick a colour and then pick the one a shade darker. It will be whAt you want. Personally, I like the Mapai grout. Seems closer to the colour chip. Laticrete is the best (Lowe's)

Hello Patty,
Getting back to your original question, "Why is this happening?", I suspect that the grout was still uncured when you had started using the shower, and that is the reason for it washing away under the pressure of the shower stream. Cementitious grouts require time to reach their full strength. Merely waiting a few days before using the shower isn't going to be enough, I'm afraid. But neither should you have to wait the full 30 days for a complete cure.
A second possible scenario is that there was water standing in the joints, perhaps from cleaning the tiles prior to grouting, when your installed grouted the shower pan? This would both prevent a bond and dilute the cementitious grout to prevent a proper cure, causing the grout to "powder out" when exposed to use.
I'm unclear about the reason your installer is choosing to remove and replace the pan tiles though? Has he/she given a reason for this repair, or have they just told you that this is what they will do to fix the issue?
Shaughnn

Hi Shaughnn- Thanks for responding. I am a complete novice with any of these tiling terms so I will do the best I can. Our installer has taken out only the floor tiles in the shower around the drain for about a foot as this is the only area where the grout has washed away (both times). He has removed them and underneath those I see what looks to be grout or grout and tiles. He's coming back Friday so I can't ask him what that is till then, but it is whatever you put over the shower pan. These must be the pan tiles you refer to??? He's not removing them, just the decorative tiles which make up the shower floor in that area. Is this making sense to you? He removed the decorative shower floor tiles yesterday and we have a fan on the shower floor to be sure all is dry underneath.

I seriously doubt there was any water standing when he installed the floor originally. Could it have been damp when he grouted the 2nd time after it originally washed away. Could have been as he did not remove the floor tiles then, just regrouted.

As for waiting until using the shower after grouting and sealing, we waited 3-4 days which is what he told us to do. (We do what we're told, believe me!) How long should we wait this time?????. We have 2 other bathrooms with showers, so we will wait as long as you tell us to. I had already decided we would wait a lot longer than what we were told to wait these other 2 times which was 3-4 days Actually I think we even waited several days longer the 2nd time he grouted and sealed. We'll wait as long as you say and probably longer than that. (: This just has to be the last time this happens!

patty, take a picture, post it and link to it here. It will answer questions better than you trying to use words. Your first paragraph above is not helping. The problem might be a fairly simple thing that can be fixed easily once and for all.

It might be serious, and the guy you hired may be covering up instead of ....

I'm not a professional per se but I've done 20 or so tiled shower pans. I can say for almost every grout I've used it normally says that machine mixing is required. Therefore I have always mixed my grout with a good drill and mixer and have never had any problems unless a tile did not properly set and had some wiggle to it.It could be a problem with a bubble under the membrane or a improper mudbed under that causing tiles to break bond. This can be especially difficult to identify if your tiles came on the mesh mats.

Machine mixing (or the lack thereof) wouldn't cause this. It would cause uneven color or mixing (meatballs), but not grout washing out. At this point, I'm with Shaughnn-- incomplete curing (or actually in this case, drying). However, 3 days SHOULD be enough time to dry completely. Not sure without physically examining it.

Sorry it has taken so long for me to get back to all you guys who offered help. Our guy finally finished the regrouting and sealing the shower floor several weeks ago and all seems fine so far! We let the new grout dry far longer than he said would be okay; I insisted. For instance, he said he'd be back on Monday morning after grouting on Thursday and I said no- don't come until at least next Thurs afternoon and you can wait another week after that if you want to. This grout is going to be D-R-Y!! Then he sealed it with what he said was a much more expensive sealer, too (at no charge to us). We let that dry a good 2 or 3 days longer than he said.

So far so good. The floor looks great so far, so keep your fingers crossed. Thanks for all the information and help!