In the late 1990s onBalance consulted for a service company on a series of pool failures in Tracy California. These pools were black plaster pools that had catastrophically whitened, in spot and trowel patterns. Three of the pools were sampled, and the cores were sent to concrete failure analysis laboratories. The petrographer reports show that plaster discoloration was associated with poor plastering practices, and not with water chemistry maintenance.
In 2003 onBalance worked with a service company in Scottsdale Arizona. The pool in question was white plaster, which was badly spotted, mottled, and in places bond-failed. The petrography report from the initial analyst determined that the spotting and mottling were the result of poor plastering practices, not with improper chemical maintenance. Core samples were then sent to a second lab for review, as well as the first lab’s report. The second lab also determined that poor plastering practices caused the defects, not water chemical maiontenance. They also peer reviewed the first report and confirmed it. Here is a write-up of that process. oB-00015