Weep holes! Not a single one of the showers I have seen in the last year using conventional (mortar) shower construction provided for mortar bed drainage by keeping the weep holes open. Time and time again, we try to impress upon everyone the importance of not plugging the weep holes with mortar. These holes MUST be kept open to allow for subsurface drainage of the mortar bed. Plugged weep holes will cause water to collect in the mortar initially leading to efflorescence and later mortar degradation by bacterial attack. Some years back I took out a 7-year-old mortar floor in gang shower with a coal shovel, literally. Bacteria that became trapped in the mortar gradually turned the mortar floor into a large mass of mold. Mortar shower floors typically stay wet once they get wet. Using epoxy grout and sealers on the tile and/or grout are not going to change that. The new water will constantly replace the old water, unless the weep holes are plugged. In that case the shower floor functions as a septic tank, not a very sanitary place to be when the goal is cleaning your body. Proper pitch of the subsurface waterproofing and open weep holes are also very important when a mortar bed is used in a deck or balcony application. All too often we see surface drains with no provision made for subsurface drainage, causing efflorescence and mortar degradation.
Last on my list due to the limitations of space is the abuse of liquid or trowel applied waterproofing systems. Liquid and trowel applied systems can provide effective code compliant waterproofing when properly applied. However, they do have their limitations. First and foremost, they are NOT all the same and do require specific application procedures for each individual product. My most recent project was a gang shower in an athletic facility in which the tile installer rolled on one generous coat of the product. He had been told by his distributor it was equal to a similar product costing twice as much. Well, it was equal to the other product in performance. But, it required three coats and full field application of a reinforcing fabric to be equal. With three coats and fabric, the per square foot cost was actually greater than the “similar but equal” product which required one coat. Water started passing through the masonry wall into the locker rooms after only two months of service. I’m not sure what product he will use in his replacement of 4,600-squar- feet-worth of backerboard, tile, and waterproofing.
As things remain ultra competitive and profits still being very elusive, we all look for the most cost effective way of accomplishing a given task. It seems the only way you can get a job the past few years is to bid it breakeven at best. That’s not all bad; we older guys have been here before, and it will pass. However, breakeven is one thing, doing something questionable or unlikely to succeed is another. From my perspective I see two things in the current market. One is many otherwise good installers taking way too many risks to land one of the few elusive jobs available. The other is floor covering guys and remodelers who don’t have a clue about the true requirements of waterproofing taking jobs they are not qualified to do. To my brother installers I say work smart and hang on; better days are coming. To those who fall victim to the unqualified and unscrupulous, I am ready and available for work throughout the United States.