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Advice on New Construction Showers

Posted by trinintybay (My Page) on
Sat, Dec 4, 10 at 8:20

I'm getting some conflicting ways of installing our showers. What are the basics we should look for in these estimates? Kind of liner, poured cement pan, or something different???? I searched on this site and saw that we should require a 72 hour flood test but how would I didn't understand all the details. Please help.

Follow-Up Postings:

RE: Advice on New Construction Showers

There's no need for 72 hours. 24's more than sufficient. As for the type of shower pan, there are several acceptable ways of completing them. But in all cases, there should be a slope UNDER the membrane, a well as in the finished surface. The membrane should come up a MINIMUM of 3" above the top of the curb, and preferrably about 6".

Your best bet would be to let them tell you what they intend to do, and then tell us what you heard.

RE: Advice on New Construction Showers

I don't know about a "poured cement pan," sounds kinda iffy to me. In a traditional shower, you install a pre-slope, put the rubber liner over that...going up at least ten inches on the studs and over the curb. Then, the walls go up...usually a concrete board, with a vapor barrier attached to the walls before the concrete. Next, a final mud pan is installed over the rubber liner and the curb is set, generally with a wire lathe and mudded to form a curb that you can tile to.

In other words, you actually need TWO "mud" slopes. The preslope under the liner allows water that migrates thru the top mud slope to travel to the "weep holes" in the drain. The reason for this, and MANY "experts" do NOT put in a preslope is that, if a liner lies flat on the floor...water WILL tend to collect there and become stagnant and mouldy.

The exception to this would be the Schluter "Kerdi" installation. In this, you only put in ONE mud bed and the Kerdi fabric is thinsetted to it. Water never has the chance to migrate to the floor. It is for this reason that you MUST use the Schluter drain....which doesn't have and has no need for "Weepholes." Google "Kerdi Showers" and there are numerous videos dealing with it. Sure, you might pay an extra couple of hundred dollars for the system.....but that is why I guarantee them for life.

RE: Advice on New Construction Showers

Oh my goodness! My mind just can't get wrapped around this information so I copied it and emailed to my DH. This doesn't sound at all like what I heard today from one of the installers giving an esimate but we are meeting with this tile/shower installer again on Monday afternoon so I will re-ask the question and post the answer. Thanks.

RE: Advice on New Construction Showers

the big thing to know and to verify is done, is that a slope be made first, before membraning. This is called a pre-slope, but all it is, is a slope. A floor sloped to receive everything else put on top of it.

The membrane is your waterproofing layer. It is the next thing to see gets done and gets done right.

Onto that slope called a preslope, there are many membranes that one could install. Choose any one method and stick to it. Do not mix various methods inside the same shower. ( Some homeowners buy some of one and some of another. Some installers have bits and pieces of various methods, lying around. And they use up their leftover material... all in one shower.)

A membrane can be a liquid (paintable trowelable). Anyone who say the K - di orange sheet is an exclusive exceptional situation simply doesn't know about the alternatives.

Which drain to use, and how to set it, is another subject that requires attention to detail.

About the slope: one can slope using poured cement. I've done it. On an existing flat level concrete slab floor, I have a sloped floor made with one pour. So, it may be possible that in your situation, this option was discussed. To buy the right product requires knowledge of the various kinds of cements, or else one calls the cement manufacturer and finds out which bag to buy, how many bags, etc. Or you go to the concrete company's web site and read up.

If you don't want a long education in this field of construction, just make sure that you check the slope is made first so that it goes under the membrane. This one thing will not show up later during flood testing. If the slope is not made first, you will get the problems described by lazarus, and more.


RE: Advice on New Construction Showers

Daviddro 1 - Thanks for explaining in simpler terms so I could understand the slope issue. I know I am over my head in this discussion but have forwarded your comments to my DH.

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