Tiling Fiberglass [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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07-31-2019, 01:04 AM
I know, I know. But I think I have an unusual situation. The house I bought last year was built in the early 70's. It has an original fiberglass shower receptor that was MADE to be tiled. Needless to say several tiles are loose, and judging by the gobs of different colored caulking smeared about, has been failing for some time.

I don't see any way of replacing the receptor without it snowballing into an entire bathroom gut job and am not ready to tackle that anytime soon.

And to complicate things, yes, there is a small amount of flex.

Last night after taking this pic I got crazy and tore all the tiles out with unsurprisingly little effort.

So I'm looking for suggestions. Right now I'm leaning towards a marine polyurethane adhesive to secure new 2" tiles and Mapei's Flexcolor CQ (its available locally) for grout. And crossed fingers.

I would appreciate any suggestions or thoughts.

BTW, the tiled section is less than 2' x 3'.

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07-31-2019, 02:00 AM
Welcome back, Jill. :)

You're in uncharted territory with that project. Even if I had a good answer for you, I'd still be skeptical because of the flexing of the floor.

Tile and grout don't like movement, and they tolerate very, very little of it before they start cracking and releasing.

How much flex are we talking about here, and more importantly, do you see any evidence of a crack in the receptor?

07-31-2019, 02:18 AM
I don't see any evidence of cracks or leaking, but I haven't scrubbed down past the globs of caulking yet.
And as far as the flex goes, how do you measure it? I don't feel any flex, but occasionally I will hear a creak, as you would in a wooden floor, so I assume there is at least some flex.
I realize this is an iffy situation, just trying to better my odds.

Tool Guy - Kg
07-31-2019, 04:47 AM
I think it would be key to eliminate as much flex as possible before adhering the tiles. Can you access the underside in a way to fill it with support material?


07-31-2019, 07:45 AM
No, not that I can DIY.

I may just wait and bump this thread in a couple of weeks. I just found out I'm soon going to have a house guest for 2 or 3 weeks and was hoping to do this quickly to get a second shower.

07-31-2019, 09:45 AM
is the fiberglass under the tiles glossy/polished??

if not, id try epoxy, at least to make it look better for the guests. honestly, in the long run nothing will probably work if there is flexing and you can't get under it to fill it with something stiff.

08-01-2019, 08:36 AM
is the fiberglass under the tiles glossy/polished??

No, it's not polished.

if not, id try epoxy,

Do you mean an epoxy grout, or an as adhesive, or both? Any product suggestions?

08-01-2019, 09:58 AM
I don't think it will hold long term, but just to stick it on and see try a two part epoxy adhesive. cover the entire back of the tile evenly. I wouldn't want to spend the money on epoxy grout. No offense but your grout looks horrid. It will be tough to match. Clean it real well then just get a caulk that matches and call it a day. Remember, this is just a temp fix that MIGHT work for longer term. If it doesn't, there is no harm done and less than 20 bucks invested.


this epoxy is good and real strong, but is kind of like thick paste. Just use the caulk as grout. It will remain flexible like your pan. A hard grout may make the tiles pop easier.

Make sure you have enough room under the tiles for epoxy. Like, if you dry set them back in, how close are they to even with the surrounding tiles? If they are VERY close and practically even, you will want a less viscous epoxy like this: https://www.amazon.com/dp/B001Z3C3AG/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B001Z3C3AG&pd_rd_w=pdlr0&pf_rd_p=8a8f3917-7900-4ce8-ad90-adf0d53c0985&pd_rd_wg=udxel&pf_rd_r=WVF09PWNYNH9SM5YA7CJ&pd_rd_r=8ae5016a-d1e3-43a4-a789-e46b092f0e78&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUE4Ujg3Q0U0VDZVTlImZW5jcnlwdGVkSWQ9QTAyMzE2MjAyQkM2M0RaOElLWDNOJmVuY3J 5cHRlZEFkSWQ9QTA3NTcwNjIzU0cyUEgxNFYzVzk5JndpZGdldE5hbWU9c3BfZGV0YWlsJmFjdGlvbj1jbGlja1JlZGlyZWN0JmR vTm90TG9nQ2xpY2s9dHJ1ZQ==

08-01-2019, 11:28 PM
Sorry Mike if I wasn't clear. ALL the tiles are history. Already on the way to the landfill. There were multiple areas that were coming loose so I just took a pic of one of them. This is my current situation.

The area to be tiled is about 2 feet by 3 feet. And I'm thinking of using 2" tiles.

The epoxy you suggested sounds better than the adhesive I found. Thanks for the suggestion.

I know a traditional sanded grout won't last but I WAS hoping something named FLEXcolor might actually allow a bit of flex. Ah, well.

08-02-2019, 12:11 AM
I WAS hoping something named FLEXcolor might actually allow a bit of flex. Ah, well.

That's actually not describing any flexibility of the actual grout. As far as flexibility goes, it has the same as any other grout. Which is pretty much zero.

clifton clowers
08-02-2019, 01:32 AM
I think epoxy is likely to fail. I might adhere the tiles with an underwater construction adhesive instead.

For grout? Not sure. Maybe use a sanded caulk instead?

08-02-2019, 07:30 AM
if you are dead set on keeping that pan and re-tiling it, just bear in mind that it will likely fail no matter what you use.

that said, I would use an epoxy thinset to re-tile.

I think it is too expensive though for your application, given the way your shower pan aesthetically looks and its structural rigidity. But it is only money, and it is yours to spend!

As to the grout, Flexcolor CQ


The product rep has stated it remains flexible and so do the ads:
-An acrylic, resin-based grouting mortar dispersed in water, with a mineral filler and additives
-Ready-to-use paste, with a consistency that makes it easy to apply
-Particularly suitable for exterior facades and flexible substrates
-Easy to apply, remove and clean from surface of tiles
-When it dries, it has a uniform color, smooth finish and is resistant to water and formation of mold

I know others here will hammer on my for this and say it is not flexible in any way, but I am simply repeating the literature and product rep comments.

It is also an expensive grout, at about 50-60 bucks for a gallon.

good luck....

08-02-2019, 10:05 AM
That flexibility is rather a relative thing, Mike. I can tell you that 2500psi concrete is not as hard as 3000psi concrete and that would be demonstrably true. But if you hit your head on the "softer" one, you wouldn't note a perceptable advantage. And that would apply even to those of us with particularly hard heads, eh?

The manufacturers of those Single Component grouts still recommend the same movement accommodation methods and spacing as they do with their cementitious, less flexible, grouts.

08-02-2019, 10:52 AM
Jill, if nobody has mentioned it this far, when you get ready to tile the pan, I would recommend you dry-lay all the tile first before you mix up any adhesive. If you don't, your adhesive will likely dry out before you can get all your cuts made and installed.

I do this on all shower floors.

08-02-2019, 11:05 AM
Thanks everyone, for your comments and suggestions. You've given me a lot to think about.

Like I mentioned, this may be on my back burner for a while.

I'll come back and let y'all know what I do and post more pics.

Thanks again.

08-02-2019, 11:39 AM
makes sense CX.

08-02-2019, 01:23 PM
I know this is a tile forum and your question was about re-tiling the pan, but if it's just to buy you time maybe you could just fill the void in the pan with epoxy? I'm thinking something like the bar top kind that is made to set up thick. You could either fill the pan with something like pebbles to add some visual interest and then just pour it in or just fill the void with epoxy and then paint on some tub and tile refinisher.

08-02-2019, 01:26 PM
She already removed ALL the tiles from the pan....

08-02-2019, 01:40 PM
Yes, I know. They'd pretty much have to be gone to do what I was saying. At least if she wanted the epoxy to adhere to the base.

08-02-2019, 01:50 PM
that would be awfully slippery

08-02-2019, 02:06 PM
Mike, that's a good point. Maybe she could cast some sand across the surface, or rough it up a bit before applying the coating I mentioned. I'm just trying to think outside the box. Anything at this point seems like a band-aid, I think the trick is to find the most cost-effective and durable band-aid.

I wonder if Redi Poxy, the epoxy used for the Tile Redi system, would work well for installing new tile?

08-02-2019, 11:57 PM
..maybe you could just fill the void in the pan with epoxy? I'm thinking something like the bar top kind that is made to set up thick.

I hadn't considered that. It sounds like a possibility worth a bit of research. I understand some may have limits as to thickness etc. and this would have to be 1/4 inch thick or so. Thanks for the idea.

08-03-2019, 09:34 AM
Digging around your old threads lead me to this place.


This just might be the way to go if they will ship small quantities. If I ever get this project done I'll post pics and an update.

08-03-2019, 09:53 AM
it's just 100% silicone. you can buy that at any hardware store.it is also not meant for tile on the floor to walk on.

08-03-2019, 11:12 AM
I found this stuff while poking around, maybe this could work? It's cheap, flexible and durable. I'd roughen up the fiberglass quite a bit before installing something like this if I were you.

https://www.homedepot.com/p/SpreadRock-Granite-Stone-Coating-1-gal-Flint-Gray-Satin-Interior-Exterior-Concrete-Resurfacer-and-Sealer-SPR-FG-004/309774897?cm_mmc=Shopping%7CG%7CBase%7CD24%7CMulti%7CNA%7CPLA%7CAll_Paint_Smart%7c71700000048001153% 7c58700004793621602%7c92700041080545918&gclid=CjwKCAjw4ZTqBRBZEiwAHHxpfjtTsISvzMjbccveoAPCnZqCBS48sb_VzlmWqXYjn_MF9G14o10dghoC-jMQAvD_BwE&gclsrc=aw.ds

08-03-2019, 11:21 AM
You may be right Mike.

Matthew, I would have to build it up to at least 1/4 inch for it to drain properly. I would definitely have to do a sample piece if I go this way.

Thanks again guys.

08-05-2019, 12:20 PM
...maybe you could just fill the void in the pan with epoxy? I'm thinking something like the bar top kind that is made to set up thick.

After way too much time on Google and Youtube I'm liking this idea more and more. I'd mix it with a coarse sand or some other fine aggregate. It would add texture to make it less slippery and would allow me to put a slope on it.

Plus I've always wanted to play with this stuff.

BTW, the Spreadrock says not recommended for shower floors, otherwise I might have gone that way.

One last question even though I know its waaaay off topic.

Do you think it's worth spending a couple more bucks for a marine product versus the standard bar top epoxy resin?