AFTER EIGHTY YEARS, IT’S TIME FOR A NEW SHOWER!

Time For A New Shower

The majority of my mold inspections take place in San Francisco, where most of the neighborhoods were built many decades ago. Starting around the 1920’s, the tiled stall shower became very common in homes and apartments throughout San Francisco, and surprisingly, many of those showers still have their original tiled walls!

Bathrooms are often the first room that I visit on my inspections, both because this is where homeowners often see visible mold, and because this is where my meters often detect moisture problems. The shower depicted in the above photo is actually fairly common in terms of the problems it presents.

The tile is cracked and broken, the grout is missing in places, and mold is visible on both the cracks and the grout. These showers were all built with “custom shower pans,” meaning that the pans built on site, where mosaic tile was installed on a mortar substrate. Under the mortar it was common to “hot-mop” the area (essentially install a hot tar roof). After these shower pans were hot-mopped, both the walls and the pan then received a layer of mortar substrate. This mortar was typically floated over chicken-wire, which was stapled or nailed to some type of building paper.

These tiled showers have lasted for decades, but in almost all cases, the grout joints have failed and water has made its way past the tile and into the mortar substrate. At Bay Area Mold Pros, we use a variety of meters to detect this moisture, including thermal imagers. One of the problems within the mold inspection industry is interpreting just what this moisture means, in other words, we know we have moisture, but has this resulted in mold growth?

The best way to answer this question is through the use of air samples. Although some amount of surface mold is often visible on the grout joints of these old showers, it is oftentimes just that…surface mold. In other words, the moisture that has made its way past the tile may not (yet) be resulting in mold growth that is making its way into the air. That’s where air samples become so important.

Air samples provide a snapshot of the air that’s present in a particular place at a particular time. The cassettes used to collect these samples contain a lab slide. The mold spores attach to the slide, and the lab techs then place these slides under high powered microspores and analyze them. These techs will break out the mold spores present both by number (mold spores per cubic meter is the industry standard), and by mold type. Even though people within the industry often refer to the “species” of mold collected in air samples, the lab actually breaks the mold spores down to the “genus” level, which is more than adequate for the purposes of identifying the severity of a mold growth problem.

The bottom line…these showers need to go! After 50, 60, 70, or even 100 years, the shower has outlived its usefulness, and it’s time to replace it. Many homeowners opt to have seamless panels installed to replace the old tiles walls, thus avoiding the problems associated with grout.

For those who choose to have new tile installed, it’s crucial to have the grout “sealed” after installation, in order to address the issue of water making its way past the grout. Properly installed tile and grout will provide years of service for homeowners, thus avoiding the need to have Bay Area Mold Pros visit your home again.