​During many recent inspections of hollow and thin-set tile installations, I've come across numerous cases where the thin-set was not bonded to the tile itself, but was instead solidly stuck to the concrete or matting system beneath it.
ANSI stands for the American National Standards Institute, and not all floor and wall tile is manufactured to the ANSI standard. Even though we, as inspectors, use ANSI and TCNA (Tile Council of North America) guidelines as our reference points, not all tile is produced to meet them.
How do we know this, or what can we use to test for it? If an attic stock of the same dye lot is available, simply turning the tile over to expose the back while performing a warpage test lets us also run a water absorption test — the same type of test used for concrete — to check the absorption rate of the tile's bisque.
When doing this, if the water absorbs into the tile in less than 20 seconds, we know the tile is highly porous. When this is raised with thin-set manufacturers, they point out that this rapid absorption pulls water out of the thin-set, preventing it from bonding and hydrating properly.
The result is that when the tile is pulled up, the thin-set is left stuck to the concrete but not to the tile. What can be done about this? If the issue is identified prior to installation, wetting the back of the tile before setting it will prevent the thin-set from being excessively dehydrated. Setting a dry, highly absorptive tile directly on top of the thin-set draws moisture out of it, resulting in a weaker bond than what is recommended.
As a home settles and substrate movement occurs, we often see hollow spots and tenting of the tile that would not have happened if the tile had been properly bonded from the start.
So who is at fault? The manufacturer will claim it did not produce the tile to the TCNA standard, so it bears no liability. The distributor purchases the tile but doesn't test it for absorption before selling it — are they responsible? Or is it the installer, the last person to touch the tile, who bears the blame?
Like many other construction problems, the flatness tolerances of Division 3 (measured with FF numbers) and Division 9 (with its standard of 3/16 in. over 10 ft.) raise questions that remain unanswered. As an inspector, our job is to identify the problem. In this case, I can point directly to the tile's high absorption rate as the cause of the defect and the resulting failure of the tile installation.

​Inspection News Notes 
 
This is designed to let people know what is happening since they attended a class and updates to things that are in the marketplace that can be used for inspections.
These are designed to be short and informative not an exhaustive discussion of the subject.  If you want to do a deep dive the links are available.
 
There is now a standard on how to measure flatness using a six foot or 10 foot level.
The A21 Best Practices for Measuring Substrate Flatness (NFCA) is published as a Canadian standard but is a standard none the less.  A standard that can be used which is better than none at all.
The standard can be found at https://www.nfca.ca
Free resources
Best Practice for measuring Substrate flatness for Floor Covering Installations
 
If there is a subject or topic you want to know more about please send me an email at George@csiflooringexpert. And we can include it in a future News Notes
 
Tools
Some great new tools are out there for inspections.
Many of the tools we use are not designed for flooring inspections but can be adapted to our needs.
You can find an Endoscope camera that attaches to your phone with a light to look underneath flooring.
Endoscope Camera with Light,1920P HD Borescope Tools with 8 Adjustable LED Lights, Endoscope with Semi-Rigid Snake Camera, IP67 Waterproof Inspection Borescope for iOS and Android-16.4ft Dual-Lens
 
This product can also work for the same reasons:
LEIPUT Ear Wax Removal - Earwax Remover Tool with 8 Pcs Ear Set - Ear Canal Cleaner with 1080P Camera - FSA HSA Eligible - Ear Cleaning Kit with 6 Ear Spoon - Ear Camera for iOS…
available at amazon for under $20 can show you under a floor with light and you can even take a picture on your phone and download it to your report.
 
If you have a tool or Ap that you are using and want to share it, please send me an email and I will include it in a future News Note.
 
[email protected]
 
Newsletter 2
The TCNA updated their installation instructions.  Dimensional troweling is now recommended as the method of installation.  If you are not familiar with this go view “Trowel & Error” on your tube.  I used to have. VCR tape of this to let you know how long it has been preached as a proper setting method.  This is located on the 2026 TCNA Handbook on page
 
The TCNA has also changed the definition of large tiles that need to use LHT (large and Heavy Tile/medium bed thinsets).  The new size standard is located in the new ANSI 
 
Tools
Check out Polycam to make 3D pictures of your job sites. (Thanks Jim)
 
If you have a tool or Ap that you are using and want to share it please send me an email and I will include it in a future News Note.
[email protected]

​Three types of flatness measurements
By George Bell, CTC, CTEF, CSMT, FCITS, IFCII, IICRC, NTCA, CFIU
CSI Flooring Expert, LLC
 
Out of Plane (OP)
The measurement taken when a six or ten foot level is set on the top of a ridge on the concrete and is level to the bubble (a plane) and measurements are taken on each side to determine the measurement on each side of the ridge.
Out of flat (OF)
An end of the six- or ten-foot level is placed flat on the subfloor and a measurement is taken at the end of the six- or ten-foot area.
Low spots (LS)
Placing a six- or ten-foot level on the subfloor identifying areas that have a dip in the subfloor and measuring both the depth of the dip and the distance between the areas flat on the surface of the subfloor. (Example: the floor had a measurement of 1/16” or .0625” in a two-foot span)
What are we trying to accomplish?
 
If installing over an OP, OF or LS subfloor area you are asking the product to bend to conform to the subfloor.  This will cause deflection and a failure in the product.  As we have transitions from glue down to floating floors floor preparation has become even more important.
Yes, we all know a flat floor can be sloped and still be flat, but the concern is that the subfloor low spots and high spots are too great that the locking mechanisms of the installed floor can come apart when stepped on.
I have read advertisements saying that some floors are stronger or using a pad will reduce the amount of subfloor preparation required for a successful installation.  When you read the installation instructions the manufacture still requires the floors to be flat within 3/16” in 10’ or 1/8” in 6’.
Why is this problem so prevalent now and not so much earlier?
This is explained by both the products and the installation systems.
At one time all LVP was glued down.  This had the product following the contours of the floor, but it did not separate or bounce.
Laminates were used we would get calls that the floor felt like a trampoline when walked on.
This was a sub floor issue, but the tongue and groove construction were solid enough to hold the planks together and bridge over the LS and OF areas.
Today with LVP the locking mechanisms are good when put together on a flat surface any deflection can cause the floor over time to uncouple and start to either gap, peak or become damaged.
Installation crews and businesses continue to treat floor prep as a “necessary evil” instead of explaining that it is only a required to have a successful installation.  Some types of flooring require more preparation than others. 
A carpeted area with padding can be OP, OF, and have LS but the padding and carpet disguise the concerns.
When you mention floor prep to a consumer most assume that it is cleaning of the floor before installation.  We should consider using a new term for this that better explains what needs to be done prior to the installation.  Consider using the term “floor flattening” as a line item on the estimate.
Each product needs to be sold with both features, benefits, and installation knowledge so a consumer can get the product and installation they are expecting.  Unreal expectations only lead to concerns and hard feelings in the future.
First published in The Inspector’s Review, April 2022 Issue 5, IICRC