It seems that every month or so, a new product appears on the market that promises either to assist us in our installations, make life easier, or help us to avoid costly callbacks and repairs. All such improvements are welcome. But often, these new products make our choices more difficult. Consider the following examples:
Anti-fracture or crack-isolation membranes. Our choices in this category run from simple one-step products and to liquid-applied formulations to sheet membranes (some of which require field-applied mastic, as well as others that have factory applied self-stick glue) and three-part systems. All of these product variations seem to perform satisfactorily.
Despite advice to the contrary, I’ve also seen continued use of building paper in on-grade installations. Doing so can lead to failures if moisture infiltrates the slab. Fortunately, the industry group that establishes related installation standards has finalized its work and submitted a revised set of proposed standards to the American National Standards Institute (ANSI) for acceptance. Unfortunately, in my opinion, the new rules include two standards -- one supposedly “standard” and one “premium.”
Bond breakers, another problem we face in our field, is addressed in a recent Ceramic Tile Institute of America field report (CTIOA Report 2002-10-15) that is available on the Internet at www.ctioa.org. This report covers bond breaker effects on direct-bonded tile using thinset methods.
Probably the most frequent bond breaker problem occurs in new commercial construction where concrete curing compounds are used. In most instances, the presence of a curing compound is not visible to the naked eye and, therefore, must be determined by testing. The most common testing method involves placing drops of water in various locations on the slab. When the water droplets show no indication of absorption, curing compounds are still in place on the concrete slab.
It is not a bad idea to use distilled water for this purpose because you can simultaneously test for the presence of alkali, which would indicate that moisture also is present. To test for alkali, simply place pH paper into the water beads on the slab and watch for possible discoloration. If you are installing light-colored marble, or marble that has a tendency to curl in the presence of water, you would do well to get a handle on the moisture situation.
If the concrete curing compound is still in place, it should be removed by grinding or bead blasting. Bead blasting will provide a better surface for mechanical bonding but it also “opens” the concrete surface pores and, thus, creates an easier path for moisture to intrude.
The CTIOA report not only addresses concrete curing compounds but other bond breakers as defined in ANSI A-108-99. A subject of particular interest to many is covered under Section A*3.1 where ANSI states that concrete should be free of oil, curing compounds and laitance. Laitance, for those unfamiliar with the term, is defined as a layer of weak and non-durable material containing cement and fines from aggregates brought by bleed water to the top of an over-wet pour of concrete. This condition can be aggravated by overworking the concrete.
Another interesting CTIOA document available on the Internet is entitled “Endorsement of Portable Test Methods and Slip Prevention Standards for Existing Flooring.” It is interesting to me that the committee’s endorsement goes to a German ramp test, and English dynamic testers. English standards are referenced but there is no mention of American testing equipment, either static or dynamic. In fact, on page 2 of this report, the CTIOA committee states that these portable tests are intended to replace the horizontal pull-meter test as specified by the American Society for Testing and Materials (ASTM C-1028-96). This test is currently in use, and is accepted both by American tile manufacturers and The Tile Council of America (TCA). There is no indication that either manufacturers or the Tile Council will agree to the CTIOA proposal.
In this litigious society, we need standards for limiting and understanding our involvements. Hopefully in 2003, we finally will get anti-fracture membrane standards and slip-resistance agreements In an ideal world, we’d also get standards on mold contamination -- of which there currently are none and, unfortunately, it appears likely that none will be forthcoming in the near future.
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