Moisture in the shower

Not an inspector, but I found this site through my web search and thought it might be the right place to ask a question, sorry if this isn’t acceptable.

I’m in the process of selling my house and just got back some requests from the buyer regarding repairs based on the home inspection. I have not yet seen the inspection report, waiting for my real estate agent to get it from the buyers. One of the requests requests in the repair addendum requests that we “investigate and repair elevated moisture readings at the bench in the shower.”

The shower in question is our master shower which I remodeled myself about 1 year ago. I used the USG Durock Shower System with waterproofing membrane to completely seal the shower (including the bench) and performed a leak test prior to installing tile. Once I confirmed there was no leak, I tiled and grouted and have used the shower for the past year without any issues. I have pictures of the construction process proving how everything was done.

I’m not sure how the inspector detected “moisture at the bench,” other than on the surface without tearing the shower apart. I assume he used a conductance type of moisture meter, which probably picked up surface water given that I showered a few hours before the inspection. I doubt he used thermal imaging, but I guess I’ll find out when I get the actual report. I’ll admit that the expansion joints between the bench and the shower wall are not 100% sealed and allow water to get behind the tile but it’s still contained by the waterproof membrane. The lack of complete seal is because silicone is such a pain to work with and I know the waterproofing is underneath that anyway.

I know that the shower is 100% water tight behind the tiles because of the waterproof membrane, and suspect any “elevated moisture reading” is due to superficial water. How can I go about proving that this is not an issue without having to tear the shower apart and rebuild it. Would a thermal scan be able to confirm there is no underlying damage? What kind of contractor or technician would be the type I’d need to hire to do this? Should I hire my own inspector to retest? Thanks for any help you can offer!

If your 100% confident in your work and abilities, then why fret? Stop jumping to conclusions and wait until you have some concrete documentation/evidence to support the findings.

Because the home inspector is claiming there is a moisture issue and the buyer is requiring me to address it before they will purchase the home. I am asking how I can go about proving that there isn’t actually a moisture issue short of tearing apart the shower.

Often, the above bolded happens. Early in my career, I did it myself. :flushed:

Some contracts may provide for dispute resolution… meaning
You are entitled to have your own inspection as a second opinion, you pay.
If contrary to the first, the two parties will choose and agree to whom the third and tie-breaking inspector will be, they share the cost.
The third is binding.
If that would not come out to you favor, tell them (you may have already) why you say it’s OK. Now take it or leave it & here’s your deposit back goodbye.
How’s that one! :cowboy_hat_face:

If the “expansion joint is not 100% sealed” where this water what penetrate this gap will go?

I’m hoping this is all there was and it’s an easy fix.

Thanks for the info, this may be what is comes down to. I guess I’ll just have to hunt around for an inspector who has a thermal camera.

The expansion joint is between the tiles on adjoining walls to prevent cracking/breaking with wall expansion, as per the TCNA standards. There is no gap in the waterproof membrane under the tiles. So in any place that water gets through a gap in the silicone, it will run underneath the tiles along the waterproof membrane and down the shower drain. This is what happens (or should) in every shower. Apparently it’s not common knowledge that tiles and grout are not water impermeable and all showers should be constructed with a waterproof backer…

It is good practice to avoid water behind the tiles, moisture could be trapped between tiles and waterproof membrane. It is possible that this was condition what your inspector found.
I would recommend sealing the gaps. Be sure that everything is dry first.

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Just out of curiosity where are you located?

I have been a bath remodeler for years. Silicone is the best option, but if you don’t want to use that, you can go to a tile supply shop and buy latex caulking that matches your grout color. Just use that and fill the gaps where the walls meet the bench. Very easy to use, cleans up with water.
That should always be done, even if the walls and bench are waterproofed.

Do your bench has a right pitch. Standing water could be defined as a wet condition.

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In some cases if you used caulk instead of grout between the pan and the shower wall the moisture that gets behind the tile in the shower can not get out no matter how tight the membrane. I use to install showers and always took pictures of the project just in case.

Just say “No”!

If they do not document water leaving the shower enclosure, consider it not leaking.
There is no test done from inside an activity used shower that will not pick up false positives.

You are not required to repair anything in a home inspection report. The buyer just has an option to “walk” from the purchase agreement.

As David said above. I might add that moisture meters are designed exclusively for wood. All other materials give ‘relative’ readings. Concrete and ceramic tile are notorious for giving false readings!

Some meters work on density. Tile is dense.
Some meters work on conductivity. Grout holds water for a long time with no ill effect.

Moisture in a bath area is to be expected if it has been used recently.

As Robert points out, you may indicate the presents of moisture, but you better explain how you achieved your findings and their validity or you may get a big fat bill for someone tearing out a shower/tub wall.

To determine a moisture issue, you must drill through to the inner wall and directly measure the moisture content beyond the water barrier. Something we are never allowed to do on someone else’s house…

Agree with David 100%

IR cameras are only accurate under certain conditions. There’s not always a perfect answer. Describe the high quality of the construction. Allow them to come back and test again after you have not just been showering (!), and decide how important this issue or non-issue is to yur negotiations… and then move one way or the other.