Installers who want to smooth out the rough spots need to stay on top of their game. As such, attendance in  training courses is invaluable. Here an instructor demonstrates substrate prep for a class of installers. Photo courtesy of Ardex.

The last time we used this space for a mailbag it proved very popular. Since that time I have been collecting more questions and will focus on those with a broad range of interests in the flooring world. The responses included here are purely generic in nature. We do not answer questions about specific products or pitch specific brands. Another thing I have learned is there are always two sides to every story. The conclusion we draw and the advice offered are based on the information provided. One reader wrote in to ask why we always hear about the negatives and not the positives. Scratching my head, I have to say I can not recall the last time someone wrote to say everything is wonderful. So, I would like to make this offer to our readership: if you know of a recent job that you feel is of outstanding quality with good technical application, please send me a note (and photo if possible). But whether it is a gripe or a kudo, we want your questions and your input so keep those e-mails coming. 

I’m not sure what to do and couldn’t be more upset. I live in a subdivision in Florida that was built over what used to be a swamp. This is my first house, so I was clueless. I had hardwood floors installed in the entire house, and the contractor put them directly on the slab. Six months later, they were buckling and mold was growing underneath. After much argument and lots of lawyer’s fees, the floor was removed and I got a small portion of my money back. I decided to go with tile, then contacted a tile contractor because I felt that was the way to go with my situation. I again and again asked if a moisture barrier was needed and the contractor assured me (as did every other tile contractor I called) that it was not. I had ceramic tile installed at my own expense (on a teacher’s salary). Cut to seven months later and the grout is turning dark in areas and white deposits are forming on top of the dark areas. Efflorescence, I assume.  I’m beside myself. What should be my response to the contractor if (as I anticipate) he insists it’s not his problem, or he agrees to just fix those areas? 

Tile will work fine in that environment but has drawbacks, which, unfortunately, you are experiencing. With rare exception membranes are made to stop water from going in, not coming out. So the contractors were correct for the most part. A typical membrane may even contribute to a failure if the wrong selection was made. There are vapor reduction products available and compatible with tile installations. Knowing you had a high moisture problem in the past, a moisture vapor emission and pH test would have been appropriate and may have foretold your current issue. The time to compensate for poor soil conditions is during the slab portion of construction. In cases such as yours, they typically install a blotter layer of aggregate followed by a vapor membrane and pour the slab over the membrane. That would eliminate the problem you are experiencing.

I do not know if it is a building code requirement in your area but often it is in high-moisture areas. Landscaping can also contribute to the problem you describe. And large-size tiles may aggravate the problem by reducing the amount of vapor passage available through the grout joints. One possible approach may be to install a vapor diffusion membrane or possibly use smaller tile. This is not a common situation and most contractors would not have knowledge of either the vapor diffusion products or application.

Also, I would hope that movement accommodation joints were used in your installation, with a free space of 1/4” along the wall line and restrictive barriers. Tile exposed to high levels of moisture experiences long-term permanent growth. While very minor, over time it places strain on the bond when the floor is restricted and may cause the tiles to arch up off the floor, a condition known as tenting. Other than possibly landscaping and air movement, such as ceiling fans, your options are unfortunately very limited. If you go the vapor diffusion membrane route, verify with the company your specific installation application via their 800 number. By the way, that wood floor you had could have been made viable by a similar process, though with a little more expense and risk.

We have a customer with an auto showroom problem. The tile on the floor is porcelain, unpolished--graphite is the color. He said when they installed the grout it was a little too light so they cleaned it with phosphoric acid, turning it darker. Over time the grout became light again. turned near white. Somebody then applied a product called “Grout Armor” on the grout lines. The problem then evolved into a daily situation. The tile would be cleaned in the evening but by 10 a.m. the next day, after only a few hours’ use, there were shoe tracks all over. When they complained to the manufacturer they were told the tile meets standards. The gent who called wants to know if we can help. I referred him to a lab that can analyze for organic films on surfaces. This is probably the fourth case like this we have seen in the past 6 months. I am curious, have you heard the same story? Is there something about car showrooms? In one case, there was near-white tile on the floor. The cars moving into and out of the showroom left tire marks that were next to impossible to clean off. We were asked why and what to do to clean it. Your thoughts?

This is actually a fairly common problem that can be avoided if the installation is done properly. Light-colored grout indicates that over-washing caused some cement and/or pigment to becoming attached to the surface. Anytime you use an acid to clean ceramic tile it burns the face of the tile. In this case a microscopic examination would likely confirm that part of the protective glaze applied in the firing process was also burned off. Under a microscope, the exposed raw surface resembles a pineapple instead of an orange. Maintenance will be greatly impacted (pineapples are much harder to clean than oranges). Use of a sealer on the grout joints offers very little value in this case. More important is a good, compacted and properly cleaned grout joint.

Based on the information provided, I will speculate that some sealer found its way to the tile surface and was not adequately removed. When sealer carrier dissipates, it leaves pore-clogging solids that give grout its resistance to staining. In this case it appears to have been left on the tile surface as well, causing a whitish appearance.

Also keep in mind that the oils in car tires commonly stain floors. I suspect in this case traces of oil are migrating into the sealer solids on the tile surface. This condition can develop even without the floor conditions described, but it is uncommon. It is known as plastizer migration and can occur on other flooring materials as well. If they did not transform the tile surface into a pineapple the problem may be a non-issue.

Bottom line: Someone who does not know how to grout used a sealer as a remedial measure-but they don’t know how to use that either. Sad to say it, but I seriously doubt this floor can be brought into a condition of reasonable maintenance without replacement. I have copied the manufacturer on this to see what they say. This evaluation would not apply to all porcelain tiles as some do not have a clear coat.

After visiting the Ceramic Tile Education Foundation’s website ( and reading  posts about qualified people looking for work, I was wondering if you offer some type of certificate that helps graduates demonstrate their proficiency–sort of a “good housekeeping” seal of approval for tile installers. Based on my experience with contractors, I would be thrilled to pay a little extra for someone with a certificate from a legitimate school. If you saw our latest botched job-a stamped concrete patio, you’d understand. Consumers will pay for quality if they can tell the difference. For them it’s cheap insurance. 

As an industry, we are considering some options on how to gain better recognition for qualified installers. We do award certificates at CTEF based on a test to assure proficiency. Unfortunately, our courses are of short duration and we have no way to truly know if that knowledge transfers into skills in the field. Experience tells us sometimes yes, sometimes no. As an industry, we are very concerned about the quality of work. It is the key to growth in our industry and we make a considerable investment (in dollars and time) in attempts to achieve this goal.

Our challenge is two-fold. First, to get people to understand the need for training, we have to get them to admit they may not be as smart as they think they are. Second, the recognition has to have some teeth to be viable.

Our focus at the Ceramic Tile Education Foundation along with that of our new industry partners National Tile Contractors Association, Ceramic Tile Distributors Association, Confindustria Ceramica (Italian Tile and Ceramics Manufacturers) and ASCER (Spanish Tile Manufacturers) is two-fold. We want to increase educational opportunities while also elevating the quality of installations. These are lofty goals, but we are making the effort. Regarding recognition for qualified installers, we continue to look for ways to provide better guidance to those looking for qualified help. Sorry I cannot offer a better, more immediate solution, but we are making a vastly increased effort over years past.