permeability
I’ve come to the world of watershaping from a different perspective. Back in the 1960s, I worked for a company that built poured-in-place concrete homes in Florida. Right from the beginning, I couldn’t help noticing the importance of waterproofing in the performance of these structures – or the consequences of not taking the potential for water intrusion seriously. My interest in this subject took on new significance in 1989, when I formed a Florida firm that conducted forensic analyses in all manner of structural failures as a service to
In the world of concrete science and application, innumerable variables have an influence on whether a concrete installation is successful or not. These include but are not limited to the skill of the applicator, the suitability of the mix design, the temperature at the time of application, the equipment used, the water-to-cement ratio and the size of the aggregate. For all the seeming complexity, however, the nature of the material itself invests the process with a few immovable facts. One of these directly undermines the swimming pool industry’s “standard” that calls for a compression strength of 2,500 pounds per square inch for pneumatically placed concrete (that is, gunite or shotcrete). It’s not because the standard is inadequate per se; rather, it’s because
Every so often, our company is confronted by the belief among certain design professionals that, as it is used by the pool industry, shotcrete is simply not viable for use as structural concrete in high-profile watershaping projects. The assumption, I’ve learned, is that the pool industry is filled with contractors and specification writers who know little about the material and therefore tend to produce substandard results. I could argue the merits of the case, but let it suffice to say that the upshot of this widespread belief is that institutions and commercial clients hesitate to use shotcrete and instead prefer cast-in-place concrete, which they perceive as having greater quality and reliability in watershape applications. We at Drakeley Swimming Pool Co. (Bethlehem, Conn.) recently encountered exactly that prejudice: A private high school that was in the process of designing and building a state-of-the-art aquatic center and an
Think about what happens when rainwater falls on an impervious surface in a big outdoor parking lot studded by the occasional tree: The water dampens the surface, which instantly becomes saturated. Only a minute percentage of water that penetrates the trees' canopies to reach their curb-bound planters becomes available to the trees' roots. The rest almost immediately starts flowing to drain grates or perimeter drainage details and is lost to a stormwater-collection system. The trees are helped only marginally by the life-giving rain, and the water
