Moisture in Shower


I am in the process of purchasing a house. Our inspector found high moisture readings behind the ensuite shower tiles, the sellers brought in their own inspector. I am just wondering if any professionals can give me some insights here on whether there looks to be an issue here or not. I have copied and pasted both inspectors findings related to this specific issue.

Thanks for your help.


Ceramic tile. High moisture readings were observed behind the tiles at the lower 3 sets of tiles at the left and right walls and the side of the door and about 4-6 ft high at the rear wall at the time of the inspection. This is an indication of water penetration behind the tiles and damage to the wallboard. These readings were approx. 20 to 90%. Recommend review by a licensed professional for repair or replacement as necessary.


2.2 (1) The shower in the master ensuite showed no visible signs of leaking, in addition, none of the grout was cracked or missing. The humidity levels that I received on the thermal camera (reference only) were in the low 20’s. Showers in general will always have fluctuating levels of humidity, especially ones like the enclosed shower in the master ensuite. Grout will typically hold moisture for 48-72 hours and if used on average twice a day everyday, the grout never really has the time to fully dry. Although there are no concerns for leaks at this time, re-sealing the grout is good practice for home maintenance (let the grout dry for 48-72 hours prior to sealing). Be sure to read the sealant specifications before using the shower again as they could require 24-72 hours depending on the brand used.

2.2 Item 1(Picture) Ensuite Shower Floor
(2) This Picture was taken in the kitchen below the ensuite shower. There appears to be no signs of moisture or water leak damage directly below the area of concern.

How did your inspector measure the wall behind the tiles? Was the inspector able to get to the interior of the wall? Showers should have a continuous moisture barrier. Water will leak through the grout/tile. If your getting moisture into the wall, you have the potential for mold and deterioration. Some pictures may help us help you. If the inspector measured the grout, moisture would be expected. Sealing the grout is not intended to take the place of proper waterproofing of the walls. Sealing keeps the grout from staining and make cleaning easier.

Thanks for replying Andrew. Our inspector used a moisture meter. Their inspector used a Thermal camera. They were not able to get into the interior of the wall, but their inspector did point out there is no damage to the ceiling in the kitchen which is directly underneath this shower.

A moisture meter does not measure moisture.
It measures electrical resistance or density changes (sometimes related to moisture).

A moisture meter is not calibrated for any and all materials.
The readings must be calculated for the material tested.

A Thermal Imaging Camera also does not detect moisture, humidity, conductivity, or temperature.
It measures Thermal Radiation, not the speed of atoms in a material or it’s temperature like a thermometer. If you want to know these things you must calculate them.

What is “reference only”?
I own a thermal camera but don’t know what the hell I’m doing with it so I am just referencing what I think it might be…

This wasn’t Bob was it?