Tile Tales of Woe
August 21, 2008
Over the past 10 years I have written nine versions of a tile complaint article for FCI about this time every year. In most past issues we have listed the top 5 problems based on phone calls and emails and called the article Tile Troubles Version x, this would be version 10. And still, like software (from which I obviously stole the title idea), the basics remain the same. For this issue I thought we would take a different approach to looking at some common tile problems by providing insight of those actually affected. For the past 6 months I have saved by topic the emails received with varying tile dilemmas. For this issue we have selected some of the problems seen regularly and a few occasionally. What appears below is the unedited email in a question-and-answer format. I included one email received, of 6, as I composed this article. The names have been changed to protect both the innocent and the perpetrators of the dastardly deeds who shall also remain innocent until proven guilty in a court of law. Just kidding! As bad as everyone wants to see a tile cop, none exist.
Q: I am building a house on the Mexican Caribbean beach and would like to know what I should consider for outdoor tile for my patio and terrace. I spoke to manufacturers in the U.S. and Mexico but keep getting conflicting advice. I would like to know if the water absorption rate is significant in determining whether I can use a tile outdoors. I have chosen one with a 2.5% rate for the indoor tile and thought to extend it out to the first floor patio and second floor terrace. The first floor patio will be covered for the most part by the second floor terrace and will not receive nearly as much tropical rain and sun that the upstairs terrace will receive. The upstairs terrace will also provide water for my cistern to collect rain water for use in the house. My question is whether I can use a 2.5% water absorption tile for the exterior floors or do I need a .5% tile. Does the fact that the upstairs terrace will be much more exposed to the elements (especially during the raining season & tropical storms) require a tile with .5% water absorption? Are there any other factors I need to consider in choosing the tile for my home?
A: I sympathize with your selection dilemma; this does appear to be a confusing subject for some reason. Long before porcelain tile, that which has an absorption rate of .5 or less was commonly available, tile has been used in applications such as yours. A very common interior/exterior application in your area is Saltillo tile which has an absorption rate of over 20%! From a historical perspective, tile with absorption rates as high as 5% has been installed in exterior applications for many years. There are numerous examples of 100-year-old installations in my home area of Wisconsin where they have remained intact under not only rain but ice and snow for 3 or 4 months a year. Most of this tile was known as quarry tile which often has an absorption rate in the 2 to 5% range. In a freeze -thaw environment a moisture absorption rate of less than 5% is recommended and 3% preferred. The Caribbean does not qualify for freeze- thaw considerations so do not feel restricted in your selection. Do be aware that moisture can cause tile to expand and heat cause tile to both expand and contract. This is something that is accommodated in the normal installation process. Please also consider that tile is slippery when wet as with most flooring surfaces. Tile manufacturers typically make slip resistance figures available and it should be a consideration in a wet environment. The most important element of longevity is a good installation of the tile product with a minimum 95% bonding coverage evenly distributed under the tile and good, full, and firm grout joints.
Q: I am the construction manager for an Olympic size swimming pool being built in Hilo, Hawaii. The pool is poured concrete, and the inner surfaces are being finished with 1” ceramic tile, in mats of approximately 12 X 12, bound with a bead of rubbery material on each edge. The initial installation had progressed about ½ way around the walls when I first inspected it, and I found that numerous of the tiles were not adhered. I have been working with the installer to demand better performance, and he seems to have obtained consistent adherence by going to a deeper notch trowel, and not leaving as wide a gap in the thinset along the guidelines. They were holding back from the straight pencil lines about ½” to not obscure them. This left ½ a tile with no thinset under it. My question is, “What is a reasonable, industry accepted tolerance for numbers of un-adhered tiles?” I have inspected their re-work several times, and each time found un-adhered tiles at a rate of about 1 every 20 square feet or more. I think that is not acceptable, but it would be unreasonable to demand that there none out of the 2,000,000 tiles.
A: There are many issues to consider in swimming pool construction such as type of tile, thinset, waterproofing, and appropriate movement joints but I will confine my opinions to the questioned asked. It appears you are having what is known as a dot mounted mosaic tile being installed. Key to the long term performance of the tile installation is complete coverage on the back of the tile to assure 100% bonding to the supporting structure. Failure to achieve complete bond will result in loose tile and grout at a later date. So, the tolerance for any unadhered tile in the 2 million tiles you are having installed in a pool should be -0-. This is not as bad as it sounds and should not present any problem for a tile professional or any additional expense to the University. One unsolicited bit of advice: allow the thinset to thoroughly cure before filling the pool with water. Depending on the tile and thinset used in this application it could be as little as two weeks or as much as four.
Q: I’m writing you today in hopes you may be able to give some insight regarding a problem ceramic job I have encountered. I’m an installer working in Southeast Louisiana. A customer called me to remove a bedroom of ceramic tile and replace the ceramic with carpet. It turns out the ceramic was installed approximately 18 years ago and according to the customer, the tiles started lifting 6 inches to 1 foot throughout the entire house about four years after the installation. This is the third job I have personally encountered with the similar problem in the 13 years that I have been an installer. I suggested a Calcium Chloride test and possible inspection by a state certified inspector. However, I am wondering what your take on this situation is. I am hoping to gain some knowledge from this, and be able to fix this job. I greatly appreciate your time and look forward to your response.
A: The problem is lack of movement accommodation joints. Tile expands and contracts when exposed to sun. When exposed to long term moisture tile permanently expands, it does not contract. In your area as many other coastal areas there is a very high water table so I am quite sure the Calcium Chloride test will measure a high vapor emission rate. A truer test of slab moisture is a Relative Humidity probe. However, neither is relative to the tile installation as there is no industry standard for moisture vapor emission for cement based tile installations. Some specific products may be moisture sensitive but by and large, short of standing water, tile can be installed over any damp surface with no fear of failure as long as movement accommodation is provided for the inevitable growth of the installation. Tile can be installed on any cement surface free of standing water.
Q: I just read your article posted on the FCI website regarding the use of crack suppression membranes. I’ve also read elsewhere that ceramic tile should never be bonded directly to a post-tension slab because these slabs are designed to flex, and tile cracking is almost assured. I have a four year old house built on a post tension slab, and I have about 2,000 square feet of tile. Thirty of the tiles are currently cracked, caused by cracking in the slab. I had a structural Professional Engineer evaluate the slab, and it is performing within spec---it’s just cracking here and there as should be expected. My recourse now is to notify the builder of the problem, and to point out that best practices or ANSI standards were violated in his tile installation. However, I don’t really know how to proceed to find out where best practices or the applicable ANSI installation standards for 2003/2004 can be found. Do you have any suggestions?
A: Post tension slabs have a long history of cracking and causing tile to lose bond or “tent.” It is well known that an exceptional thinset or even better a membrane meeting industry standards is highly recommended in post tension applications. The recommendation can be found under method F113 in the Tile Council of America Installation Handbook including the year you referenced, but it is not part of the ANSI standards document. The Ceramic Tile Institute of America (CTIOA) has a published field report, 2003-7-21(R 4/04) which could shed some further light on the issues. American National Standards Institute (ANSI) is a voluntary guideline so there is no “violation” per se unless the standards were referenced as part of your contract. “Best or common practices” vary by region and are usually established locally, and often in conflict with industry recommendations. Unfortunately, we can only provide technical advice and while we agree with your concerns, cannot suggest a course of action.
Membranes and Movement Joints
Q: My tile floor has failed. It was installed in 2004 when my new home was built. The company used an anti-cracking material between the tile and the concrete floor because most builders in this area believe that it will save them money because they will have to deal with less cracked tiles. The paper separated from the concrete floor leaving my tile floor free floating on the concrete. About two months ago a complete row of tiles going across the middle of my living room tented up from the pressure and the tiles being loose. This is how I discovered the installation materials used. The anti-cracking material appears to be made out of paper with a waxed coating. I have seen the term “craft paper” and it may be this product. The paper was stuck to the tile but completely loose from the concrete floor. Between the tile and the paper was thin set. The material that was used to attach the paper to the concrete was a mastic glue which dissolves with water. (I put water on the glue to remove it from the concrete. Some of the glue was left on the concrete and some was transferred to the paper on the back of the tile. I believe the floor failed because of the cheap paper used and the fact that it was attached to the concrete with a water soluble mastic glue. The contractor told me that this method was acceptable by the Tile Council of America prior to 2005 but in 2005’s handbook, the council revised their findings and advised contractors not to use this method any longer. Is this true? They claim they stopped installing tile this way in 2005 based on this finding. Can you help me determine if the contractor’s information is correct?
A: I have been a member of the TCA Handbook committee many years and can say only on very rare occasion is a method withdrawn and none has in the last 10-15 years. The last removal was mastic over moisture resistant drywall which was a result of both building code and changes in construction practices. I am not sure of the products used in your application but use of paper type products have a long history of failure. It has long been a problematic issue which has been discussed and written about for years. TCNA never approves any specific product nor have they ever recommended the use of a paper product as a crack isolation membrane. The current American National Standard Specification for Crack Isolation Membranes for Thin-set Ceramic Tile and Dimension Stone Installation ANSI A118.12 [New 2005] came about because the industry had an awareness many products were being used with claims of performance that were not technically possible. This standard applies to trowel applied, liquid, and sheet membranes and was developed to provide those selecting products and installers with the minimum criteria necessary for a material to function as a deterrent to crack propagation from the substrate through the finished thin-set tile or stone installation. I am not sure how that relates to what you have been told. Typically failure of inferior products and methods will not occur till after the warranty period has expired. I have been involved repeatedly in instances related to paper products used for crack suppression to the point where I have a form response letter I use. The use of such papers is rampant in various areas of the country and it is a widely know mode of failure in the professional community. The National Tile Contractors Association recently published a document which may provide you with further insight. While your focus has been on the paper used for a membrane it is only fair to point out the floor actually tented prior to its discovery which is a different issue, lack of movement accommodation joints in the tile installation. I suspect, as commonly done, your tile was grouted into the wall or wood trim. That actually compounds the issue; the sheared tile area may be much greater than you think. It is unlikely any repair of the floor will be effective for more than a minimal time period. While the patch may be effective for that area the adjoining tile may well buckle in the future.
So this was not a top 5 or 10, just a glimpse into the daily email. Having saved them since January, I have 217 more failures and responses to paste in this article but I don’t think FCI will give me the space. We don’t make these things up, these are real problems that happen to real people They then lose not only the comfort zone of their former dream home but also incur thousands of dollars in repairs and untold hours of aggravation. They needn’t have suffered any of the above failures if only their installer were properly educated and/or created an awareness of potential issues in the installation. Tile Cops or not, it just seems criminal that these and hundreds like them must suffer personally and financially. If you have ANY questions about installations or products, contact your preferred manufacturer before use or installation. They will gladly help you with the proper product selection and execution. If they don’t, find a new partner who will. I have never known a reputable company that was not anxious to assist in any installation effort regardless of size. If you don’t avail yourself of their services and wait till after problems happen, don’t take offense at manufacturers less than enthusiastic response. Sad but true; 97-98% of the time when it comes to tile and related issues, it is installer related. I am an installer; I know!