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vapor barrier needed in basement bath??

9112 Views 9 Replies 4 Participants Last post by  AGWhitehouse
i am rebuilding a basement bathroom from the frameing up. In the new shower & room walls should i be putting some type of plastic on the frameing before wallboard or hardibacker. i have 1 small window and no fan. i asked this question in the plumbing forum and some links were suggested but they did not answer this question. i have heard "yes" it's needed and I've heard it makes things worse. any ideas? thanks, j.
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Yow that is arguable either way you won't get a right or wrong answer when masonry or concrete walls are involved underground.

If it were me...I would not. I would however waterproof the face of the wallboard and even that will raise an argument from some.:yes:
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to vp or not

thanks Bud. One wall of the shower is against the foundation wall, all of it but 1 foot is below grade. we don't have any moisture issues, no water in the basement, no effervecence (sp?) etc. When you say "water proof the face of the wall board" do you mean the drywall/sheetrock or the hardibacker or both? and with what? should i seal the hardibacker before tile?, and again, if so, with what? I did seal the foundation wall with an elastomeric type material though. jv.
Waterproof any wallboard inside the shower. I'm hoping you don't have any drywall in the shower interior.

There are several liquid waterproofing products available to you.

Home depot selld Redgard.
Menard's sells Mapei HPG
Lowe's has a TEC product I think.
Latticrete sells "Wall and Floor Waterproofing", "Hydroban", "Product 9235", there are several others.
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I wouldn't; I estimate that you are in a 'cold' zone and in cold zones, we try to have the moisture that comes through the foundation walls, dry to the inside of the basement. We no longer put up 6mil plastic vapour barriers that only trap the moisture inside the concrete.

So if you had no shower at all, you'd have an insulated stud wall where water vapour comes into the basement. But now you have a shower down there, you want to continue drawing moisture into the basement but you have to manage it appropriately by installing a good fan that takes the excess moisture out of the bathroom and sends it outside.

That's the way to control water vapour; now as for physical water, waterproof the drywall - or whatever you make you shower walls from - by using a waterproofing membrane. These membranes slow down the transmission of vapour but prevent the drywall from even getting wet at all.

So 2 water things you have to manage: vapour and droplets.

Your local building codes may have something to say on the matter, so check it out.

Sure, you'll get a variety of opinions on this but the choices are clearer for those of us in cold zones, where, during the winter, we need moisture on the inside.
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not to vp!

thanks guys. The interior of the shower is "hardibacker" brand wall board then tile. I have been reading about taping and Redgaurd. I understand if i do tape that it goes on JUST ahead of the tile so as to not get bumps and the redgaurd would be first? Do i need these steps with the hardibacker? I have also been hearing the term "hotmopping" what is that? I have done some small tile projects and am pretty handy but there really is so much more to this tiled shower!! I plan on having a pro tile friend come and help me thru the crub and pan process. I have jack hammered the floor to get the drain right and have a plumber on site as we speak who will be connecting it to the old pipe. Any other thoughts? Really appreciate the feedback. jv.
ccarlisle: "I wouldn't;............."
See what I mean!
It's Arguable.:yes:
Yeah even old farts, even those born in 1947, don't always see eye to eye...LOL
As was said, I would only recommend waterproofing within the shower stall. All other walls of the bathroom should be left as standard construction to allow for moisture dissipation if it should get in the walls. Being in a basement area, moisture is always present even if you can't see it. Concrete never stops giving off moisture. You need to allow the space to dry, so I would only recommend ensuring that the direct water from the shower is properly controlled (waterproofing) into the drain. The rest, I would put up moisture-resistant sheetrock, paint and enjoy...
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