enter image description hereenter image description hereSo I have recently had a tenant move out and have found water damage around the basement shower floor. Looks like black mold so I started ripping it out. Now I am at the point where I have found what looks like a undersized water barrier but not sure if I need to bust out the concrete or just remove the perimeter and pour over the entire thing... if I do need to remove the shower sub-floor what the best way to do so with out damaging the foundation. Also notice how it looks wet, yet it hasn't been used on 25 days. There was a tiled corner chair I have since removed, thats what was in the corner.enter image description here

Thanks for you helpenter image description here

  • What's the hump for on that breaker bar? I've never seen one like that.
    – Mazura
    Mar 28, 2016 at 2:01
  • @mazura for pulling nails - with a normal one you'd put a wood block under so you can push the other end down. This one rocks on the curve. Pretty smart idea actually.
    – Grant
    Mar 28, 2016 at 3:50
  • Yeah its called a super bar at most places, had this one at least 15 years.
    – JoeLaser
    Mar 28, 2016 at 12:03
  • The wet 2x4 makes me wonder if water was just getting around the door instead of through the membrane. Either way, at your current point of demolition, I'd keep going, remove the 2x4 and existing water barrier.
    – BMitch
    Mar 28, 2016 at 12:20
  • @Mazura You should post that as a separate question.
    – Tester101
    Mar 28, 2016 at 16:28

2 Answers 2


The tile adhesive is not bonded to your foundation. The rubber membrane is installed between the foundation and adhesive. You definitely want to remove/replace. enter image description here

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  • 1
    Awesome advice, I actually came on to say I figured it out... once I popped that front board off I could sledge the pry bar under the slab raise it a bit an pop it with the sledge on top busted up nicely but holy crap it is heavy. Hope the kids feel strong this spring break. LOL I will post the followup pic. So where do I get a form that will fir exact?
    – JoeLaser
    Mar 28, 2016 at 11:59
  • 1
    Depends on how you plan on finishing the shower and the dimensions of the shower space. But, if you are trying to basically go back with what was there before (except better), you can pick up the pan liners and liner adhesive at Lowes, HD, or a plumbing supply house. Usually you'll find the Oatey brand. I'm going to post some photos that I hope you will find very helpful. Also, I too believe the water damage is from leaks at the corners of the threshold and not a leaking pan.
    – bigbull15
    Mar 28, 2016 at 15:06
  • Actually I think the biggest issue was the corner tile chair they built in. I didnt cut the barrier, it only went that high up the seat. Also was for sure leaking at the 2x4 the the sliding door was on, the builder did over wrap the barrier as in your pic it just went up as high as you see it nailed there. I will post the pic before I started to show the tiled chair.... barrier should have went all the way up imo.
    – JoeLaser
    Mar 29, 2016 at 5:40

All of that should be torn out and replaced with backerboard, which is then coated in a waterproofing membrane, to be tiled over and sealed.

Or it can be replaced with the same modern type of dry-pack mortar bed, of which I'm not a fan and neither are you anymore I bet. That's why I opt for precast shower pans whenever possible (they also come with a lip).

"We're just going to go over the old stuff," are words I never want to hear. There's no way to verify the substrate unless you just put it in, or at least get down to it to inspect it. This is your opportunity to do so, to insure your install lasts the next 30 years no problem.

(I wrote the above without realizing this install must be on a slab, but then why is there a 2x4 in the floor? And why would you dry-pack over a slab?)

Re: damaging the foundation, you probably will to some extant but hopefully it will just chip in some places which is easily leveled back off with some patching. If cracks do develop in the slab then you might be looking at having to re-pour that whole section.

Chip at it from an angle with a hammer and chisel or the equivalent power tool, don't just start whacking it with a sledge hammer.

This is a rental, it's not choose your own adventure bath time. Get a manufactured shower pan and slap it in there; no self-built or on-site custom shower pans (as you've learned, they like to leak). Purchased pans are like mini bathtubs; they only leak if you install them wrong.

  • You dry-pack over a slab to create the necessary slope to the drain weep holes, then you apply a waterproofing membrane on top of that. Then you dry-pack again to create a sloped finish substrate to which you bond your tile. Mar 28, 2016 at 3:03
  • Thanks again. I was able to get the superbar under it a bit and pry it up and hit it with the sledge while it was lifted. Broke up pretty nicely.
    – JoeLaser
    Mar 29, 2016 at 5:47

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