Hydro Ban or Redgard (and insulation bonus question!)

SignmasterJune 25, 2011

First post, I've been lurking for a while and finally registered and got done with some lengthy searches.

We're doing a remodel in the bath, and I wanted opinions on the use of waterproofing materials to use over the Hardibacker. I want to do things right, and the differences in opinion on these two products seem to be at best, very great.

I like the idea that the Hydro Ban is not a vapor barrier, as I could use poly/felt to put a barrier over the wall studs. On the flip side, it's twice the price of the Redgard which some seem to say will do the same job. In my case I'll only need a couple of gallons (above tub tile only) to I'd rather eat the extra money if needed.

Does use of Hydro Ban actually require using their thinset for the tile, or will other brands of thinset work and adhere just as well?

The above leads to my second question. The home is split level, with the bath being the "split" and the first thing on the second level. Essentially the long side of the tub faces my downstairs attic, with only the studs between the two.

I want to increase the insulation between the tub wall and attic to minimize temperature swings and drafts. I'm assuming if I use the Redgard on the wall that I have to use a vapor barrier free insulation to do this to avoid the "moisture sandwich" situation. But if I use the Hydro Ban and a felt/poly barrier, could I use an insulation with a vapor barrier? They would essentially be a single vapor barrier consisting of two back to back materials, which in my mind would be similar to adding two layers of poly or felt rather than one. Is my thinking backwards in this regard?

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collins design

I can't answer all your questions, but I did use Hydroban and loved it.

I chose Hydroban on the advice of several pros. I'd had mold issues before and wanted to do everything I could to ensure I was using the BEST product out there. Hydroban was wonderful to work with!! You do not need to use their thinset.

    Bookmark   June 25, 2011 at 9:22AM
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If you use either membrane on the face of the hardi, there's no need for the vapor barrier in a standard tub/shower combo. The surface membrane would mbe more than sufficient. The only time I would worry about the vapor barrier in conjunction with a waterproofing barrier would be in the case of a steam shower. That said, if you WANT to use the vapor barrier behind the hardi, then you want to go with the Hydroban, for the very reasons you cited.

    Bookmark   June 25, 2011 at 9:38AM
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Everything that Bill said is correct and I will add that if you want to use Red Guard then use their thinsets, grout etc... If you want to use HydroBan then use the Laticrete products!!! IMHO, Laticrete has the best products on the market and offer the best comprehensive warranties as long as you use the products correctly. HydroBan is my go-to choice and I use all of the products as well.
On a side note, I find Durrock Next Gen to be a much better product for preparation of shower walls if that is available to you.

Todd Stull
Enola, PA

    Bookmark   June 25, 2011 at 11:42PM
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Thanks for the input everyone.

I've seen your DIY results and it's good to know that you were happy with the Hydro Ban. It does me no good to have a great product that isn't DIY skill level friendly.

Call me paranoid but I did want to use a vapor barrier over the studs if possible. On the attic side I think it will help reduce temp variations, and on top of that it will just help me sleep better at night... and I can use the sleep. In the scope of the overall renovation the money is a drop in the bucket for the extra insurance (at least in my mind).

I'll look into the Durrock Next Gen, and points taken on staying within a product line for the waterproofing and thinset products.

I'm still not sure of my concern about the back to back vapor barriers. Does anyone have any input on this?

I've got special orders coming in, not far from the demo stage at this point. :)


    Bookmark   June 26, 2011 at 1:43PM
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For what you're asking, use unfaced insulation. Then put 6-mil poly the wall, that'll give you a decent and continuous vapor barrier.

While there's nothing wrong with Hardie, it's sort of double-edged...I think DIYers find Hardie easier to cut/fasten/install than Durock but they find Durock a lot easier to tile over due to the water-wicking nature of Hardie. Nothing wrong with either, but personally I prefer cement board over fiber-cement.

I'd recommend Hydroban due to you wanting to use poly as a true vapor barrier. Personally I wouldn't use Redgard on an exterior wall that has a vapor barrier behind it. If you prefer to use RedGard, then ditch the poly and use tar paper between the studs and the cement board.

Tar paper isn't a true vapor barrier, it's a somewhat weak vapor retarder at best. Its perm rating varies depending on humidity, but it's always well above the threshold needed for it to qualify as a true barrier.

You can use anyone's thinset over Hydroban. Or RedGard. But I do think Laticrete's thinsets are a little more consistent than Custom's. That written, I've used my share of Custom's modified thinsets over the years and haven't had problems.

    Bookmark   June 26, 2011 at 4:57PM
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Thanks a lot for that input Mongoct. Since it was grey area for me I was assuming tar paper was considered a true vapor barrier. I'm having trouble locating Hydro Ban locally, and it may save me some time and expense to be able to go with the Redgard in that case.

Between the input from yourself and Todd, I'm pretty much sold on going with the Durock now.

    Bookmark   June 28, 2011 at 5:17AM
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Just another idea...

If expense and sourcing is a concern, do understand that you don't need either RG or HB.

This is a tub, and tubs surrounds see water exposure, but not as much as the lower walls of a fully tiled non-tub shower or the tiled pan of a shower floor.

Let's say your horizontal tub flange is will be 18" above the floor after the tub is installed. Run a 24" high strip of 6-mil poly horizontally across the bottom of the tub wall. Detail the poly at the sole plate as required. Set the tub. That previously installed piece of poly will now extend 6" above the height of the tub flange.

Now run a generous bead of caulk horizontally across that exposed 6" of poly, say 3" above the tub flange.

Now hang another sheet of poly horizontally across the wall from the ceiling down to a couple of inches below the tub flange, with the bottom edge hanging into the tub. Detail it at the ceiling, lower down press it into the bead of caulk. Let the excess overlap the tub flange and hang into the tub a few inches. Depending on the style of your tub flange you can just let the poly sit as-is, or you could lift that overhang and run another bead of sealant on the tub flange to seal the poly to the flange.

Install your cement board. Cut the excess overhanging poly off at the bottom edge of the cement board with a sharp utility knife.

That'll provide you with a continuous VB behind the tub, as well as draping the poly over the tub flange if needed for drainage, and save you the cost and labor of installing the topical membrane.

    Bookmark   June 28, 2011 at 11:31AM
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Signmaster-- where abouts are you that you're having a hard time finding Hydroban? You can email me, if you'd rather not say in public.

    Bookmark   June 28, 2011 at 6:18PM
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Thanks for the additional scoop. I am aware I don't need both the barrier and topical membrane, but I wanted the extra insurance more than anything. I'm also doing a couple niches on the back wall and most think that should involve the waterproofers, so at that point I figured it would work well and be safer to use on the entire backer surface.

Piece of mind = sleep better at night. Sleep is good.


I'm in Virginia Beach. I tried a few places and got either no Hydro Ban or contractor only sales. I haven't had much time to dig for other sources yet. If you know of one that sells retail it might be a time saver. I wouldn't even mind buying from a contractor that sells it as long as they don't try to bend me in half on price.

    Bookmark   June 28, 2011 at 10:29PM
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Might be a bit of a drive, but try this place:

4253 Lankford Hwy.
Exmore, VA 23350
Phone 757-414-0567

Talk to Dona and tell her I sent you.

    Bookmark   June 29, 2011 at 9:48PM
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bill I posted a message about redgard earlier I believe on a different page but it was asking if redgard would stick to rock. and can I go under my morter or should I go over the morter? I have a pour a 10x12 pan with a drain and go 2 ft up walls ALSO new question... this waterproofing is going to be for a small brewery where there could possibly be a spill. it is going to have ceramic tile.. but for waterproofing a 10x12 area would laticrete9235 or hydroban be better than redgard??????? Thank you!!!

    Bookmark   April 28, 2013 at 2:53AM
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