This week, I am going to devote time to answering and sharing a recent mold/indoor air quality issue question that came my way. It concerns a very specific way of installing HVAC ductwork, where the HVAC ducts have been placed in or below the concrete floor slab. To better illustrate this to you, I asked a contractor to describe the installation process to me. Here is what he said:
“As the home is being built, trenches are dug in the soil before the concrete foundation is poured. Wooden or concrete blocks are then placed in the trenches and the HVAC ducts are pieced together and placed in the trenches on top of the blocks according to the home’s layout and the HVAC blueprint. Many times, the ducts are in direct contact with the soil. Concrete is then poured around the ducts as they lay in the trenches. Finally, the concrete slab is poured on top of the ducts/trenches to form the home’s foundation.”
This practice of in-slab ducting has become notorious for different types of problems, like functional troubles (lack of air flow or collapsed ductwork), and environmental problems (radon, odors, flooding, mold, insects). The main reason I want to address this question on the blog is because of the many indoor air quality issues inherent in this type of construction that I think people need to be made aware of. I also think this question is an important one, because it involves all of the components of needing to be a “mold detective” and a health advocate for yourself. This is because watching out for potential health hazards in your home and other frequent indoor environments can protect you from long-term health consequences. In other words, if it smells like mold, you can see it, and/or your body feels “off” in a particular environment and like something is making you sick, chances are that your body is right, and it is mold or something environmental. Thus, you have nothing to lose by taking steps to safeguard your health by investigating and fixing your environment as soon as something seems amiss.
So, let’s begin. Here is the question that sparked this post: