Water rotting bottom plate, where's it coming from?

[bmbouter]

My friend's bathroom is on a concrete slab. Near the shower there, for years, the wood has slowly rotted. Several folks replaced drywall, but didn't look much further. It's next to a shower. The shower's been retiled twice, and the shower pan has been replaced once. Everyone thinks it's coming from the shower somehow. Anyways, it's happening again. On one side of this is a bathroom and the issue is where the wall meets the walk-in shower. On the other side of the wall is a garage. We opened up the wall from the garage side today to see, and found the bottom plate 40% moist and black.

The damage is very localized (see pics). It's on the slab, so (to me) there are only two possibilities of where it's coming from a) the shower, b) standing water from the garage which could have gone unnoticed perhaps. They did have garage water issues and it does slope towards this wall.

I can't see what is behind the triple stud, so it's hard to find the source, but there just isn't much space back there. The part of the bottom plate I can see is dry and seems well in tact (see pic) so I just don't think it's from the shower. The material above the wet spot about 18" up reads a nominal 18% damp so I don't think it's water coming down.

There are two sections of cracks in the tile grout near this spot. Is it possible that water is intering through those cracks? What could be going on here? Also if this were your house what would you do?

Thanks!

 

[ShaunCorbs]

Would say the shower is a fault best thing to do if they have another shower is to let it dry out and see if it either drys out or stays wet over the next month etc

Probably not waterproofed the shower area where it meets the pan

 

[bmbouter]

Well the shower was used today, and now there is a small puddle on the concrete on the other side of the wall. So I think we know the water is coming from the shower.

What I don't understand is how two contractors can have come to fix it, untiled, retiled, reinstalled the pan, etc, etc and it still is basically the same problem. Is this a difficult job to get right? What does fixing this entail? I don't plan to do it myself, but obviously my strategy of deferring to "a professional" doesn't seem to be working. Any advice?

 

[ShaunCorbs]

Tbh rip out and start again new timber work etc backer board, new shower pan and waterproofing the shower area totally have a look a schluter

 

[Timmy D]

I’d bet it’s the shower screen/door. Looking at one of the pics, it looks like it’s been grouted on the outside.....screens are quite particular about how they’re installed and sealed.

I’d have a shower, see the pool in the garage and then take the screen off to check for water behind the wall frame work.

It’s likely water is getting in the frame and the horizontal/vertical wall joint behind the frame is letting water through.

Also step into shower has grout along the bottom edge, it’s cracked. Should be silicone to resist movement.

If the simple stuff like this is wrong, you can bet nothing is right.

 

[bmbouter]

Thank you all for the responses! You all are the best.

When you say "the screen" what does that mean? Is that the shower door hinge?

 

[Timmy D]

Thank you all for the responses! You all are the best.

When you say "the screen" what does that mean? Is that the shower door hinge?

The glass shower inclosure wall mounts.