Recent Updates to Ceramic Installation-Related Guidelines
The Tile Council of America (TCA), National Tile Contractors Association (NTCA) and Ceramic Tile Institute of America (CTIOA) are responsible for a number of advances in our industry. Together, these organizations have done much to standardize tile installation methods in use today.
In particular, the NTCA has provided new or replacement documents for insertion in their reference manual. The first is a lighting placement document that explains why harsh shadows often act as a “wall wash” that can impinge on the beauty of a ceramic tile wall. This document offers suggestions to alleviate shadow problems.
In general, there are three suggested means of addressing wall shadow problems. The first is to locate light fixtures at least 24 inches away from the wall, preferably in the center of the room. The second suggestion is to avoid the use of ceramic mosaics and scored tile where wall lighting is necessary. And the last suggestion says that maintaining smooth, flat wall or floor surfaces within the standard tolerances established by the American National Standards Institute (ANSI) will reduce shadows.
The second NTCA document provided is an update for page E-29, Bonding Large Size Tiles. This document illustrates a new procedure that improves coverage, support and reduces lippage. The procedure requires the installer to comb the mortar in one direction only. Traditionally, mortars have been applied in a swirled pattern -- which makes it virtually impossible to beat-in or press and move large-format ceramic tiles.
The new method was devised for ceramic tiles 16 inches rectangular and larger (up to 36 inches). This simple procedure requires flat toweling to key mortar into the substrate, and then the mortar is combed in one direction. Next, the tile should be laid and pressed into the mortar and move perpendicular roughly 1/8 to 1/4 inch across the ridges. Then, reverse the movement of the tile that 1/8 or 1/4 inch to flatten the ridges into the valleys between the mortar beads.
This procedure is very effective in reducing hollow-sounding tile, attaining required coverage and supporting corners so that they are less susceptible to cracking.
For their part, the CTIOA has released report #2002-10-15 entitled, Bond Breakers On Concrete Slabs And Their Effect On Tile Installed Using A Direct Thin-Set Method. The CTIOA has had a series of tests performed to determine and compare the effect a “bond breaker” has on the bond strength of a dry set mortar. The bond breaker used was a common concrete curing compound. The test assemblies were evaluated on a Tinius Olsen Universal Tester.
Bond breakers can take the form of various substances such as curing compounds, sealers, coatings, paint, pre-existing flooring adhesives, grease, oil, dead cement, dust, dirt, and surface laitance. (Laitance, for those unfamiliar with the term, is a layer of weak material that contains cement and fines from aggregates bought to the surface by bleeding water from the concrete to the top of over-wet concrete due to water-cement ratio or overworking the concrete’s surface by improper finishing.) Concrete additives and even finishing techniques such as steel- or rotary-toweled concrete can yield a slick, shiny and dense surface.
CTIOA recommends the application of a few drops of water around the slab to see if it penetrates readily. If the water does, the slab is free of potential bond breakers. If the beads take a few minutes to penetrate, it is a sign of contaminants below the surface. When the water beads show no sign of penetrating the concrete slab, bond breakers are present.
In addition, the institute has outlined a procedure that was first adopted first by the Coefficient of Friction subcommittee and subsequently endorsed by CTIOA. This procedure is entitled, Endorsement Of Portable Test Methods And Slip Prevention Standards For Existing Flooring.
These standards are addressed to both the ceramic tile industry and resilient manufacturers who currently, in their ASTM-F13 committee, designated underwriters 1047 testing the James machine. Questions are sure to arise here because the ceramic tile industry for decades has specified in their ASTM committee C-21 the static tester C-1028-96. The CTIOA advocates the demise of the C-1028 even though it’s testing device is preferred by ANSI.
CTIOA says the Tortus Floor Friction Tester can be used but the pendulum may be substituted. CTIOA also says the pendulum may yield more conservative test results. I guess it depends upon whom you represent when you pick your instrument -- Tortus for the plaintiff, and pendulum for the defendant.
Slips and falls remain a highly serious problem in our country. National Safety Council statistics indicate that more than 1,200 Americans die each year as a result of slip-fall incidents on the same level (not on a ladder or stairs, etc.) The economic cost is staggering -- in excess of $4 billion per year.
In my work as a flooring expert, I personally don’t advertise or go looking for slip-fall cases. However, in the last month, I have been asked to participate in two cases. One claim is for more than $1 million. If you want to avoid similar legal headaches, my advice is to make sure you don’t have any lippage (or at least chemically alter the face of the product) or tile that doesn’t meet current municipal standards or industry recommendations.
In my next article, I’ll cover updates to the new TCA handbook.