I have asked this question over at John Bridge, and they didn't know the answer, so here goes.

I have a second-floor studio, I'm putting in a small bathroom with shower. I had the shower professionally glass-matted when the studio was built, and am just now getting around to tiling. Ran out of money, time, we all know the story.

Anyway, I'm wondering how I should proceed from here. The fiberglass is thick and heavy, and includes thin 'extensions' up the walls about 18". The 'glass is laid up and over the top of the kerb. The preslope is formed in the 'glass.

For the walls, I'm planning 1/4" Hardibacker, with shims to keep it flat down at the bottom where the fiberglass comes up the sides. Also making sure not to pierce the 'glass with screws or nails.

So what do I need to do on the shower floor? Can I just thinset the tiles right on the fiberglass, or do I need a membrane? I have about a gallon of Mapei Aquashield, I used it on the bathroom floor before I tiled it (over Hardibacker: I love that stuff.) I was thinking about a couple coats of Aquashield over the Hardi and the fiberglass floor, THEN set the floor and wall tiles.

Speaking of which, is it better to set the floor first, or the walls? Does it matter that much?

Thanks so much!

chris

Follow-up question: How does everyone feel about epoxy grout? I'd like to do that 'pebble' tile on the shower floor, but it means there's a lot of grout between the 'stones', a friend who has it says it's kind of hard to keep clean. Seems like epoxy grout would reduce that problem.

Whaddya think?

Fiberglass, if done right, should be water proof. I would start with a water test. Plug the drain so absolutely no water can escape that way, and fill the pan with water. with a sharp pencil draw a line at the water line. Let sit for 24 hours. If it proves water tight, then no further water proofing is necessary.
Just rough it up a little with coarse sand paper and tile over.

Yes, water proof the hardy. Generally I set the floor first. this is because you are putting a rectangular product in a dished space and all the edges are tapered. the wall tiles hide the edges.

You might want to try GreenE board, which is a white magnesium board well suited to tiled showers and much easier to work with.

How will the water that seeps under the tile escape down your drain? Just check that it can or you will end up with moldy grout.

Thanks Pete! So, no mud bed required between the raw fiberglass and the thinset/tile, right? The laid-up fiberglass is solid as a rock, it's not anything like those flexy pre-made pans.

I've got the drain pieces but have not checked everything out yet, so I'll have to see how it's set up to allow drainage. I think I understand the concept though: there are basically two drains, one for 'above the tile' and one for 'below the tile'. I've just gotta get in there and see what's what. And do that leak test before I go much further, that's a great idea and cheap insurance to prevent a disaster.

I've been concentrating on the floor and getting the throne set in place, the shower is next up on the list.

Time to get busy: getting married this year and the little missus insists on two bathrooms. Can't say I blame her, actually.

Thanks again, I'll probably pick your brain again soon...

c.

Yes, no mud bed required if there is no jell coat. I'm assuming you have a somewhat rough fiberglass pan. On the drain there should be two slots in the threaded part to allow water to escape.

Pete, thank you so much! You have made my week. Month. Now I know I can have a functioning shower before my lovely bride moves in. Relief.

You're exactly right, the 'glass is rough, no glossy finish coat. It looks about 3/4" thick in the floor, thinner up on the curb, but still pretty beefy.

Now I can start shopping for shower floor and wall tile. Yeehaw!

Thanks again!

c.

Update:

Checked out the shower drain, it does indeed have several weep holes around the perimeter of the main drain. Looks like I'm ready to rock the walls, apply Aquashield, and start tiling.

I found several pieces of granite at a local place, they leave their scraps out for scavengers like me. It's already bullnosed, perfect to make niche shelves, and FREE. I'll still have them cut and bevel the curb topper for me though.

Trying to find decent-looking 2x2 tile for the floor. Found some gorgeous stone, but it's $$ and requires extra care, like sealing and whatnot. 2x2 ceramic tiles are very plain, but hey, I'm not building the Taj Mahal.

Did some research on Mapei Opticolor two-part grout: the folks over at John Bridge forums seem to like it. And Lowe's carries Mapei, that makes it easy.

Thanks again for the help!

c.