Air leakage in our Florida homes is a major cause of indoor mold and poor air quality yet most “mold assessors” or “mold testers” fail to identify, or even inspect, for air leakage when they conduct indoor air quality or mold testing. Advising you have elevated spore counts of some specie of mold without identifying the source of the mold is a waste of your money. Frankly, most mold testers have no clue why you have elevated mold or what the counts mean.
The chart above (credit to Certified Commercial Property Inspectors Association) is an excellent example of how small gaps/openings in our structure increase the amount of moisture in our home. One square-inch opening in our wall increases the moisture gain by a factor of 66. Think of it this way:
- A tight home will allow about 1/3 quart/month (.07/qt per week) of moisture to enter the interior.
- If we have one small hole, the moisture increases to 33 quarts/month or 2 gallons/week.
- If we have four small holes, the moisture gain increases to 132 quarts or 8 gallons/week. Compare this to the typical family of four who produces 18 gallons of moisture per week by bathing, cooking, etc. The moisture load on the HVAC system has increased by nearly half and the system was not designed to treat a 50% gain in moisture.
Load calculations for HVAC systems are based on new construction. The calculations do not incorporate building materials’ obsolescence into the design load.
Envelope Leakage Testing
When HVAC systems are replaced, we rarely conduct new load calculations or conduct Envelope Leakage Testing, aka Blower Door Testing, but we should. A typical infiltration rate (air changes/hour at 50 pascals) for new construction is about 1.5 to 3.0 ACH. Older, leaky homes are closer to 10.0 to 5.0 ACH or at least 3-times more air changes/hour than a new home. The State of Florida requires blower door testing on new construction, but they do not require testing on existing homes when HVAC systems are being replaced, but they should.
Industry statistics show that our aged homes have an average of 173 inches of air loss related to gaps, cracks, duct leakage, failed windows, missing weatherstripping, and inefficient air seals. Using the chart above, that relates to over 1,427 gallons/month of moisture, or 42 times the average amount generated by normal activities such as bathing, cooking, etc.
Mold growth requires moisture. No moisture = no mold. It’s just that simple.
When “mold testers” sell air sampling to determine if there is a mold issue in your home, they are basically selling snake oil. The air sample has no idea how tight the home is or even where the air being sampled is coming from. A 5-minute air sample is basically a meaningless sample. Further, it is a “non-viable” sample, meaning it cannot tell us if the mold spore is even capable of growth (viable). Many “mold testers” will compare an indoor sample against an outdoor sample to determine if a mold problem exists (if indoor is higher than outdoor, there is an issue in their opinion) yet, they have no way of determining where the indoor air originates from. Most mold testers, and even mold assessors, do not know that less than 1% of any given mold spore is capable of growth even in the best circumstance. If every mold spore was capable of growth, there would be no human life on this planet.
When the “mold tester” provides a mold lab report showing 10,000 potential mold spores per cubic meter of air, understand this:
- It is a mathematical supposition and cannot be correlated to any scientific evidence.
- Multiply the number by 1% to derive a worst-case number of “what could be possible”. In other words, 10,000 spore counts of any given mold is, at best, 100 potential spores that could grow if they landed on wet drywall. Doesn’t sound quite as scary now does it? How many of those do you think would land on a given wet spot? I’m guessing maybe one.
Find the Moisture
If you do have an indoor mold issue, what is important is to determine the source. We must find the moisture. When we remediate/repair the source of the moisture, we have solved the mold problem.
Common opportunistic molds like Aspergillus/Penicillium and Cladosporium always relate to elevated humidity or condensation. In short, these molds do not require an active leak to exist and flourish. They thrive on low-level condensation or elevated humidity. Elevated moisture in indoor air relates to:
- Inefficient HVAC systems
- Poor ventilation
- Excessive air infiltration thru our exterior walls, ceilings, windows, doors, or floors
Skip the “Mold Tester” and Call Property360
If you think you have an indoor mold problem, you need to skip the “mold tester” and seek out a building analyst who is qualified to assess your home/office. If not, you are simply wasting time and money.
Property360 provides qualified indoor air quality and mold assessments in NE and Central Florida including Jacksonville, Palm Coast, St. Augustine, Lake City, Gainesville, Daytona, Orlando, and all areas in between. To request an inspection, contact us at (904) 606-1570 today!