Please help! Shower bench pitched incorrectly and made of OSB

[swbosley]

Hello!

First of all, I sincerely appreciate any input/advice you guys and gals can give me.

The problem: we have a shower enclosure with a ledge/bench topped with white subway tile. The tile was pitched incorrectly when it was built so water would just pool at the back, even after using a squeegee. The house is about three years old.

I'm a pretty handy guy, so I thought it might be a simple fix (too much thinnest buildup on the front - so just remove the tile, and reinstall the tile with less thinset and pitch it correctly); however, when I was tapping on the tile on the left side of the bench this morning, it just popped right off with next to no effort. The enclosure is made of OSB, and the OSB is soaking wet and just crumbles apart.

Clearly, this is not going to be a simple fix. I am attaching several pictures so you can see what I am talking about.

Two questions:

1. What did the builder do wrong?

2. How do I fix it?

Going after the builder probably isn't possible, so just assume I have to fix it myself or have it fixed.

Again, I appreciate any advice. I'm here to learn!

[speed51133]

First off, sloping the tile will not really help much. The water still gets through tile and grout. The substrate below the tile, the actual bench itself should have been built with a sloped top. Basically, anything directly under the waterproofing layer should be sloped on any horizontal surface.

Your osb bench looks like it has some kind of green coating on it. Could have been a painted on waterproofing coating. Thing is, osb should never be used as a substrate in a shower, and is not at all meant for waterproofing.

I recommend you tap around the whole shower and especially the curb and see if any other tiles pop off...

[Kman]

Welcome to the forum, Scott.

Looks like a waterproofing membrane (maybe Aquadefense?) over sheetrock.

The reverse slope is what killed it.

You have some demolition to do, and it likely won't end with just the bench. If you just fix the bench, the problem will likely move to another area, if it's not done so already.

For starters, remove the glass. Take careful measurements of the opening and height of the bench, as you'll want to try to replicate them if possible. You may not be able to reuse the glass, though, considering you'll be changing the slope of the bench.

Demo the bench and see what that looks like underneath. Then you'll have an idea of how much further you'll have to go.

The bench will have to be sloped from the glass to the edge to shed water. My bet is you'll find damage around the front and back of the tub.

[swbosley]

Thanks so much for the responses! Is it ever acceptable to use OSB board in a shower setting? How about around the bathtub? I’m assuming if the bench/ledge is made from OSB, the surround around the bathtub will be, as well.

[cx]

Welcome, Scott.

Nothing at all wrong with that material in those applications if used correctly. Doesn't appear yours were.

My opinion; worth price charged.

[swbosley]

Thanks CX! I’m curious: what are the steps you would take to fix the issue?

[cx]

You don't wanna know.

I'm not thinking that's a repair job at all. Unless you just need to hold off on a full replacement for a little bit while you save up for a new shower.

And for that I'd need to see more demolition of the bench area to even suggest a temporary patch.

My opinion; worth price charged.

[swbosley]

I would love to hear some other opinions. If I were a customer and I called you out to my house, what would you tell me? What would your advice be?

[Mdsims]

I'm just like you: a homeowner. That said, I just finished building my own shower and have a lot of construction experience. I had the cash to hire someone, but wanted it done right and my labor market is full of 'know-it-alls'.

"If I were a customer and I called you out to my house, what would you tell me? What would your advice be?"

1. Demo the rest of the bench, see what you're working with. What you see for the bench is likely to be how the tub surround was built. With a flashlight you may be able to see what's going on under the tub ledge.
2. Carefully remove all the glass, measure to reinstall later.
3. full demo down to framing, if this was a recent job, reuse framing but level it all out, if old job, new framing. Remember that on items like benches, the framing sets your slope and pitch, not the tile, not the thin set.
4. Pick a membrane based waterproofing system (Kerdi or USG Durock) and get to work.

[Davy]

With the seat built like it is, you can guess how the rest of it is built. If you called me out, I'd give you one price, to replace the whole thing.

[rmckee84]

Like Davy said, if I came out to look at your job I would shoot you an estimate for a full gut and redo. I wouldn't give an option to fix it.

[swbosley]

By full gut and redo, are you just referring to the bench, or are you referring to the entire shower, bench, and bathtub - meaning, 100% of the tile?

[Lou_MA]

If you called me out for the work, I’d quote full gut of all tile and complete re-do. Once I touch the work, I own it.

And even if clients tell me they’re ok with “just fixing part of it”, when the “other part” has problems they usually feel like the last person who worked on it is responsible.

[Davy]

The shower seat is a continuation of the tub deck and it's most likely built the same. I'll bet the moisture goes back under the glass into the deck. So yes, the whole thing.

[swbosley]

If you were to use OSB in a shower, what would you need to do to make sure it is waterproofed correctly?