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Shower pan install

Posted by tylerstem (My Page) on
Tue, Feb 18, 14 at 3:41

I began the slow process of building a shower pan. It has a wood subfloor. I got in a hurry and forgot to put down tarpaper before filling my floor mud in! Do I have to take it all up and start over? I only used about 100-140 fluid ounces of water to make all my mud. Is that enough to rot the subfloor?


Follow-Up Postings:

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RE: Shower pan install

The tar paper isn't to protect the subfloor from the moisture in the mud. The paper is placed to act as a slip sheet to prevent the mud from sticking to the subfloor.

The moisture in the mud will be consumed by hydration, or the curing process of the mud. Any excess moisture will evaporate out.

What are you going to use for waterproofing on top of the mud?


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RE: Shower pan install

I am using Oatey 40 mil. I always thought that a moisture barrier had to be between wood and any mixture that had water in it. Example, every time I install a laminate or floating floor on top of a concrete slab, I always put down a moisture barrier so the floor doesnt absorb the water out of the concrete.


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RE: Shower pan install

A moisture barrier over a slab-on-grade is a different thing. Because the slab is on earth, the slab will always allow moisture to go through it. Moisture will move from the more moist area (the earth under the slab) to the drier area (inside your house).

The barrier you put on top of your slab prevents moisture from the earth from continually coming though the slab and causing your floor boards to warp/buckle, etc. The earth under your slab will never "run out" of moisture.

With your deck mud mix over a plywood subfloor, there is no continual source of moisture. There's only the water you added to the deck mud. Once that moisture has been consumed via hydration or evaporated away, that's it. It's dry. The deck mud preslope will be dry. Your subfloor will be dry.

Your Oatey membrane will keep the deck mud preslope, as well as your wood subfloor, isolated from the wet shower.


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RE: Shower pan install

Well, when you say it like that.......it makes sense!! Lol. Thanks! I feel 1000% better! Tomorrow I start the rest of the shower pan. Thank again!


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RE: Shower pan install

No worries. Good luck with it!


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RE: Shower pan install

No worries. Good luck with it!


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