Mortar Shower Pan Joint to Wall DenseShield Backer Board Always Wet.

In a new house built in 2013, Shower is tiled with mortar base on sub floor with shower 40ml membrane, I can only assume but probably wrong that the proper layering of materials along with slope were used. Sub-floor, Tar Paper, Lathe, mortar base sloped, Shower membrane, install drain with weep holes, mortar base then tile. I know this system is meant to allow the seeping of water through the mortar to the shower membrane and then drain if all proper as these shower setups are not 100% water proof to drain all water off the tile surface, due to grout, cracks, joints, etc.
I had to open part of the opposite wall of the shower to get to some piping to repair a pin hole leak in a soldier joint. After a few days of drying out the area I happened to pull back the rubber membrane and noticed about 2" of moisture wicking up the edge. It did not reach studs or other exposed surfaces as the rubber is about 6" high around perimeter. Pulled it back and tried to dry all out, still used the shower side though and noticed it just never dried out. The mebrane is doing its job.
Long story short now is this normal to have this section constantly moist? Do i consider it a poor install and question the builder? I believe it should be dry more than wet, what concerns would longer term? The backer board is DenseShield at least but it still wicks water up the fiberglass mesh. I don't think it will get higher than the 6" but you never know....
Comments or suggestions always help. Thanks.

 

As long as the moisture is within the shower pan, you have little to worry about as far as issues with rotting framing and or subfloor. Use a level and check the slope around the drain inside the shower to make sure that a slope was indeed set. One thing I have seen is that the plumber sets the membrane and leaves it straight on the subfloor without any pre-slope. This would cause water to seek its level at the lowest spot which may be the corner you are looking at. Only way to check this out is to look at the drain from underneath for signs of a pre-slope. Other than that would be removing a section of base plate to see if there is mortar under the pan - I would not recommend doing this as you may damage the pan in the process.

What I would do is make sure that the corners in the shower, both horizontal and vertical are well caulked without breaks. I would also get a heavy duty grout sealer and apply multiple coats to the grout. This should assist with some water resistance and slow the migration of water past the tile. You also can squeegee the floor after each shower and prop the door open to promote drying of the shower area. Also be sure to use the fan in the bathroom to pull out excess moisture while you are showering. Setting the fan on a timer sometimes makes it easier for you to run the fan for a length of time after you finish your bathroom activities.

 

Thanks for the comments. Your thoughts are pretty much in line with what I was thinking to mitigate some of the water seepage as well. The builder of course says its to code and is functioning as expected, although the amount of acceptable seepage is debatable. Unless you do it yourself or see them actually build it, you will just never know.

 

I have to ask--why on earth are you performing plumbing repairs (i.e., pin-hole leak) on a new home that's less than one year old? Do Canadian builders not include a new home warranty for such things?

 

You know, I ask myself the same questions regularly on a multitude of services.
Yes we have a 1 yr home warranty (hence dealing with the builders trades people), if you want to wait the 24hrs for the plumber to come by and re-solder a joint, while your water is left turned off. So many trades (not all, met and know lots of great ones) take advantage of home owners and think they have no clue. Well some of us actually do and have done many renovations in the past. I cannot use my guys unless I want to pay out of pocket and then try to get it back. If I didn't feel comfortable I would have left it, I had the water back on in 30 minutes after the discovery.
The Mortar Pan though is so frustrating as I only use pre-fab bases from Schluter or Wedi and their water proofing wall systems. Never had issue. Every time I come across a mortar and membrane system, everyone has had an issue at one time. If i had designed the house/bathroom I would have definitely done it differently.
I talked to the city for the building code some more and all that is required is that it has a water barrier membrane or equivalent to prevent water damage. It does not state how to do it just that it is required. This is also what the builder is telling me. So my only recourse is to see if the warranty portion covers not following OEM install practices of the DenseShield. As it looks like they either used the Dense Shield to form the mortar perimeter or they put it right on top in contact with the mortar bed. The other part of the warranty states that even though an issue may be present, until there is actual damage (mold, rot, etc) there is no claim until it happens. The fine print is ridiculous.

 

Will mold grow on fiber glass or rubber? Or is it only if it comes up to the stud uncovered wood area? I thought it had to have some organic type material in order to grow on.

 

If it's any consolation--mold will grow wherever there is heat, moisture and a food source. Your fiberglass or rubber may have plenty of micro-organisms to keep a mold population quite happy (and productive).

If I'm not prompt in keeping my BBQ grill clean, I've seen mold grow on the steel grates within a week after use.

P.S. The last photo in your initial post reveals something interesting--there doesn't appear to be any grout or caulk to keep water from sneaking in behind the vertical tile/pan tile junction. A tight-fitting butt joint just won't cut it. If this junction were to be sealed, I suspect you might not see a lot of moisture migrating into the wall members on the back side.