Custom fiberglass pan below tile shower floor

[TileGuyCanada73]

I was talking to a friend who has a lot of expertise with fiberglass for boat repairs. When he built his shower, he wanted it to be a custom size/shape and didn't want to use a product like Kerdi. Instead, he manufactured a custom fiberglass shower pan in place. First he built the base of the shower in plywood. Then he started adding sheets of fiberglass and resin. This was all done in-place in his house. On the top layer of resin, he put sand into the mix so it would give the mortar something to adhere to. Then he just tiled the floor as you normally would. He seemed to think this was all pretty normal but it sounds fairly unique to me. Have you seen this technique used before?

[ss3964spd]

Lots of un-knowns there, Steven. How did he seal the drain to the fiberglass pan? Did he slope the pan towards the drain? Does he know the mortar adhered to the sandy resin or is it, and thus the tile, just sitting on top of it? Where does any moisture that gets into the mortar go?

[cx]

The problem, Steven, begins with having no good method of connecting the fiberglass liner to an appropriate shower drain. Perhaps he found a way to do that, perhaps not.

Bonding tile directly to fiberglass may work OK. May being the operative word there.

I can't imagine that he is saving any money or time using fiberglass to manufacturer his own fiberglass receptors and I can't think of a good reason to do it, but if he likes his method and wants to use it, that's fine with me.

But I'll not be recommending it to our visitors here.

[TileGuyCanada73]

Yeah he did talk about how he sloped it and mentioned the specific challenges of ensuring he could achieve a good seal to the drain. I won't be doing it myself. I'm more just wondering if anyone has ever seen this done before?

[cx]

Built-on-site fiberglass receptors are almost de rigueur in The People's Republic of Austin, Texas, Steven. I've never actually seen one go in, but it's my understanding that they use the fiberglass as a liner in a traditional installation with a second mortar bed on top of the fiberglass. I don't know how they connect their fiberglass to a drain, nor even what kind of drain.

The only major remodeling project I ever did up there I brought my own tile man from San Antonio and we did traditional receptors using PVC liners.

[e3]

I don't believe that this method would meet the National plumbing codes...(UPC or ICC)

[Davy]

When I was in high school, I remember my dad installing a few fiberglass pans. While the fiberglass was still wet, he would bolt the top flange in place. I have no idea how well everything sealed off. I know one thing, that stuff sure stinks up the house.