Moisture Reading on Ceramic Tile Shower Floor

(system) #1

When my home inspector performed a home inspection, he used a moisture meter to detect moisture around the walls of the shower, but I have not seen him using the moister meter to check the ceramic tile floor of the shower.
Recently another home inspection was done and the inspector used a moisture meter to check the ceramic tile floors. Moisture was detected by the meter. I suspect some area of the grout may be moist and requires re-grouting and application of grout sealant. Visually, the shower floor has no sign of mildew or water damage. There has been no complaints from previous occupants including myself.

My questions are:

(1) What is the standard practice for home inspectors when inspecting the shower floor? Can they use moisture meter to check shower floor?
Another inspector says that he usually do not use moisture meter on the shower floor unless there is visual signs of moisture problem.

(2) If moisture meter can be used on shower ceramic tile floor, what type of moister meter should be used?

(3) (if you can help me further) what are the proper repair processes to address the moisture issue?

Thank you in advance for your help.

(Charley L. Bottger) #2

Shower stalls are somewhat touchy to inspect for leakage if the ceramics are not visually broken. A moisture meter is of little use if the home is occupied and the shower stall was used just hours before the inspection. The grout will retain enough moisture to read high on the moisture meter. I personally prefer to use thermal imaging for shower pan leak detection

(ldapkus1) #3

The standard practice to inspect a shower is a visual inspection only. If any instruments are used to detect moisture, the inspector is going beyond the Standards of Practice. However, most inspectors have moisture meters to inspect suspect areas.

(Joe Funderburk, CMI) #4

Many older homes used wire mesh in the concrete substrate. A moisture meter acts like a metal detector also. Other than destructive testing, observation for visible leaks is the only way to check a shower stall. I flood a shower with 2" of water and look for leaks around (and below) the shower.

(system) #5

I have ceramic tile on the guest bathroom floor and stone tile in the master both and closet.
Moisture readings on both read 95 to 100% on a capacitance type meter is this correct?

(Chuck Evans, CMI TREC 7657) #6

It’s not abnormal. The tile will sit on a mortar bed. The waterproof shower pan will be under the mortar. The capacitance moisture meter will detect moisture in the mortar on the wet side of the shower pan. The tiles and grout are not waterproof. You can’t check for a leak by sticking a moisture meter on the tile.

You have to check for leaks from outside (on the dry side of the shower pan) the shower pan. The fix for a leaking shower pan is to tear out and replace it.

(David A. Andersen, TN HI# 40) #7

Both inspectors don’t know anything about using a moisture meter. For one thing a moisture meter is generally calibrated for wood. Cement products are not water proof.

As Chuck pointed out, testing is to be done on the other side of the tile, and that is not accessible without intrusive inspection (which is outside the scope of a home inspection).

As Charley pointed out, Thermal Imaging is the appropriate non-intrusive test for testing a house you don’t own.

It is very likely that you do not have any problems here, other than having unqualified inspectors.

(David A. Andersen, TN HI# 40) #8

This is a bath tub leak Chuck documented: This is how it’s done if you really want to know.

(Stephen W. Stanczyk, WA License #221) #9

There is also the possibility of a metal shower pan or even metal lathe installed under the tile in which case your moisture meter would most likely get the same readings.