Hello All, this is my first post, so thanks for any help you may be able to lend. I have an approximate 6' X 6' bath I am remodeling. It has only the tub/shower and toilet in it. Demo is almost complete (not much to do in so little space). Main questions are about vapor barriers. This is the master bath and am putting in a jetted tub 3' X 6' along the interior wall, except for an open chase up to the attic space in part of one wall this seems to be " normal" for CBU and a Mapie(?) sealer for the vapor barrier, I think (Please let me know if I am off base here). The rest of the side wall is partly exterior, partly open to the attic space and partly interior, there was no insulation behind the existing tub/shower enclosure. The remaining walls are door to master and exterior. We are planning to have house resided soon and all walls will be wrapped with Tyvek. ANY suggestions. 18 X 18" tile on walls only around tub/shower and 1" mosaic on floor.
THANKS, Mel

Welcome Mel
First, we are going to get you to answer a few questions for clarification.
1. Is the new tub/shower on an exterior wall or interior wall?
2. Can you give us the actual product name of the Mapei item you're thinking of using? I'm not aware of any sealers from Mapei other than their concrete sealers. Do you mean waterproof membrane?

The Tyvek will have no bearing on the insulation or vapor barrier within the home. It's primary purpose is to reduce the air flow into the wall cavities. It's not a vapor barrier.

Thanks, Randall. The new tub is all interior walls. But on the short side with the drain the slope of the roof that is over the lower level cuts across the area that will be tiled wall. Sorry the Mapei Aqua Defense is a membrane(I am used to calling sheet goods membranes and anything in a pail sealer).
I am trying to figure out the best soundproofing and insulating system to fix the nonexistent system that was here. Thinking foam board or something like it and if the Tyvek won't hurt may cover the spaces between studs with it, this bath has always been hot in summer and cold in winter,now know why. I just don't want problems with moisture, this is Georgia and we have a gracious plentitude of that.

If you could possibly post some pictures of the area in question,that would help.

As you know any area that is considered to be exterior exposure must be insulated and covered on the interior side with a 6 mil vapor barrier as per your local building codes. The exterior side of the wall may or may or may not be required to have an air barrier as per local codes.

Now, the complicating factor is the introduction of a waterproof membrane. What you don't want is to possibly trap moisture in the tile underlayment layer, especially if it's not cement board.

I'm not 100% sure that Aqua Defence is rated as a vapor barrier. You may want to contact Mapei technical support for that one. I do know that Laticrete HydroBan is not considered as a vapor barrier and is ok to use over an existing poly barrier exterior wall.(as per technical support)

As for foam board, the same theory applies.

If you were to use a full vapor barrier rated waterproof membrane or underlayment board on the tiled walls that are on the exterior wall then you would not use a vapor barrier over the studs/insulation. (Please note that this would be against building code, so if this is being inspected it would not pass.)
Some of the products that would be in the above category are as follows:
Schluter Kerdi membrane
Schluter Kerdi Board
RedGard waterproof membrane (liquid)
Wedi Board
DensShield Board

There are other manufacturers products which may be available in your area that I have not mentioned.

As you can see this is not an easy issue to sort out.
You need to know exactly what products you are going to use and follow the manufacturers installation specifications.

If you can tell us for sure what products you intend to use, we can assist you further on the appropriate installation method.

Clear as mud!

Thanks Randall, the Aqua Defense is a waterproofing and crack isolation membrane. I have some pictures but don't know how to get them onto this post. Will switch to a computer from this Ipad and it may be self evident.
If I am following so far it will be alright to wrap the areas that are exterior but will not be wrapped with tyvek when the siding is done (roofline and attic openings), then insulate all walls with foam board (for sound and temp control), then 6 mil poly vapor barrier over the exterior walls (how do you transition or end the vapor barrier when the wall area continues to interior? This area is the upper wall of the living room, no high humidity or cold air). I will check how to close up the ceiling openings into the attic. Then CBU's then Waterproofing crack membrane, mud, tile, grout, sealer. The area outside the tub/shower area will be green board and paint. Have a lot of work to do on the floor, but that is covered pretty well in the other posts. I do have one other question on the wall tile, we want to put an accent strip of the 1" mosaic about 5" high, this tile is thinner than the 18" X 18" tile which has a rounded edge and we don't mind the difference in thickness as long as it doesn't cause any other problems, question is how do you treat the grout at the meeting edge, just try to smooth with sponge?

The Tyvek is only applied to the exterior side of an exterior wall, not the interior side.

Foam board is not a good sound barrier. It actually amplifies the sound transmission. You are better off with glass type insulation bats. If you do use foam board such as Styrofoam SM or equivalent,then DO NOT put a poly barrier over the foam board.

There is also no need for green board outside the tub area. Regular drywall works just fine and is less expensive.

For the mosaic strip you normally would build up this space with thinset first so that the two different tile surfaces become flush.

If you need help on the above method I could explain it further in more detail.

have some pictures, (Harry) how do you post pictures? Thanks, Mel

Go to the Forum titled Ceramic Tile and under the sub heading Post PHOTOS of the project you're having trouble with.
Follow the instructions in the sub heading forum to insert your photos.

Any replys will be posted in that forum for the photos you have inserted.

Thanks Randall, will try to post in the next few minutes

Any special kind of tape? is the support of the studs enough for CBUs without any additional bracing to screw them to? What about ceiling, does it need any slope, I may need/want to tile the ceiling over the tub, if so there will be a box dropped from ceiling to support track for floating shower closure panels. Thanks

The tape is called sheathing tape and is red or white in color. It's used for Tyvek seams, Styrofoam board seams and poly vapor barrier seams.

The ceiling does not need to be sloped. That's only a requirement for steam showers.

Ceiling joists should ideally be on 12" centers for cement board but not absolutely necessarily. Make sure to follow the manufacturer's installation instructions for the product your going to use.