Mold Testing by Remediator

Treating for mold without first having confirmation that there is mold might make a remediator legally liable. Listen to this story.

A story: The remediator treated for black mold, and the homeowners got their money back.

This elderly couple noticed black mold on the foundation wall in the basement. Burt and Gertrude had read newspaper accounts about “toxic black mold” and were very apprehensive about the mold in their basement. They called in a basement mold specialist who confirmed that this was black mold. He quoted a price of $13,000 to clean up the mold and their basement, and install a Humidex (now called the Wave) ventilation unit.

Burt and Gertrude were retirees were on a fixed income, and $13,000 represented the bulk of what they had in the bank. Still, they were concerned for their health and took seriously the fear-mongering of the remediator.

The work was done, and then the trouble started. Gertrude had increasing breathing problems, and twice ended up in the emergency room. Somehow they found their way to my service. I came out to the house and heard the story.

When they showed me where the black mold had been, I asked if any testing had been done. They replied no, that there was no mold testing by the remediator, that the remediator just proceeded with the cleanup. I explained to them that Stachybotrys, the black mold featured in many media pieces, seldom grows on concrete. In fact, I’ve seen a little of it on concrete only once in 20 years. The chances were very high that the mold on their foundation wall was common Cladosporium, the mold that would grow on a windowsill or in a bathroom ceiling. They could have wiped it off with Borax sprinkled on a damp sponge or brushed it down with vinegar. They were dismayed, to say the least.

I referred them to an attorney, and he went after the remediator. He got their money back for them. The charge was something like “sale of unnecessary services.” The remediator had no defense, because he had not done any testing and could not demonstrate that there ever had been mold, let alone that it was anything other than common Cladosporium mold, the type of mold that might grow on a shower curtain.

The second issue here was the Humidex (now called “the Wave”) ventilation device. I’ve had some good feedback on this device, so I’m not negative toward it. However, it does discharge air from the basement, and when air is discharged, makeup air has to come from somewhere. From what I understand of installation instructions, there is supposed to be a vent to upstairs at the other end of the basement so that makeup air passes downward into the basement. A window should be cracked somewhere upstairs for makeup air.

When there is not a good path for makeup air, then makeup air can be drawn from undesirable places. For example, makeup air might be drawn from an attached garage, and homeowners could smell car exhaust in their basement.

At Burton and Gertrude’s home, the makeup air was being drawn in from the backyard. Unfortunately, their backyard faced the trash area of a corporation. The chemicals used to sanitize the trash area were being drawn into their home. These chemicals were causing breathing problems for Gertrude, sending her twice to the emergency room. Needless to say, the plug was pulled on the Humidex, and that solved Gertrude’s breathing difficulties.


  • Having confirmation of the presence and type of mold is a first step before agreeing to remediation. Independent testing can protect both the homeowner and the remediator.
    New York and Florida are two states that have regulations stating that a company has to make a decision whether they are going to do inspections or remediation, that it’s a conflict of interest to do both.
  • The Humidex ventilation system, now called the Wave ventilation system, is presented as an alternative to a dehumidifier. I like alternatives to dehumidifiers, which use a lot of energy and which also, particularly in block foundations, may do damage to the foundation over a prolonged time period.
  • That said, I don’t have much experience with the Humidex/Wave or comparable unit. If you investigate and decide to purchase the unit, learn the lesson of makeup air.
  • Other clients bought the Wave and reported the following: It saved them about $200/month by replacing their three dehumidifiers and doing a better job than the three dehumidifiers. The basement odor was gone a few hours after installation. Note: They were using central air upstairs, and this conditioned air was cycling down into the basement. Improvement in basement air would likely not be so dramatic without central air.The Wave representative indicated that even though outside make-up air is being brought into the house, money will still be saved as the basement dries out and the central air doesn’t have to work as hard.

Question: Did you just say that dehumidifiers can damage foundations?

Response: An old-time waterproofing contractor taught me that. He said that when the relative humidity is lowered in a basement, then moisture will migrate from an area of higher humidity, from the soil around the basement, through the foundation wall, and into the basement. As this moisture migrates through the foundation wall, it picks up lime, which is like the glue that holds the concrete together and which is water-soluble.

He told me how when his waterproofing crew dug down to the footings on the outside of block foundation walls, sometimes they would find the concrete eaten away from years of using a dehumidifier.

I was called to a Cape Cod house for a mold inspection a long time ago. The homeowner brought me down to the basement and pointed to a half-inch layer of whitish fuzz-appearing material on his foundation walls. I knew what that was, and it was not mold. It was lime and other mineral deposits coming through from the outside and from the foundation wall itself. I referred him to a concrete professional for an evaluation of the integrity of his foundation.

The house had mold issues, including the basement, but those were in addition to the white mineral deposits.

Story: Woman double-checks what mold remediator tells her

Getting a second opinion is typically a good practice. “Nellie” saw some discolorations here and there in her home. She called in a mold remediation company. Their representative walked around and confirmed that the discolorations were mold (without any testing). He totaled up an estimate for mold remediation for a cool $18,000.

Upset, Nellie started searching online and found my website. She learned that for a nominal fee, she could send me tape samples for examination under the microscope. After reading the instructions for mold testing, she sampled eight spots with clear tape and forwarded the samples to me, with a check for $50. Her accompanying note told of her worries about the developing situation with mold at her home and her hopes that I could help her negotiate her way through it all.

I received her tape samples, and, one by one, put them under the microscope. I found no mold in any of them. When I called Nellie to tell her this, she was astonished. Here are the points I made clear to her:

  • Discolorations may or may not be mold. Confirmation is possible under the microscope, but not by the naked eye.
  • That said, a simple at-home test can be helpful in ruling out mold for some spots. Touch the spot with clear tape, and then hold the tape up to the light. If there is nothing (or only grittiness) on the tape, the spot is probably not mold. If there is a filmy discoloration on the tape, that might be mold.
  • The mold industry is, unfortunately, ruled by visual inspections. Many professionals seem to think that if they can’t see mold, it’s not there. Unfortunately for the homeowner, a lot of mold is invisible, and so the mold professionals miss it. Conversely, too often mold professionals assume that discolorations are mold when they are not.

Lesson: If this woman had blindly relied on the judgment of the remediator, she would have been out $18,000.

Story: Buyers run when remediator quotes $30,000 to treat the basement for mold.

The buyers had put money down and signed a contract to purchase a home. Three small areas of discoloration were noted in the basement, and the homeowners brought in a remediation contractor who gave an estimate of $1500 to treat these areas. The buyers brought in their own mold remediator, who came up with a $30,000 estimate to treat the basement. After hearing $30,000, the buyers believed that there had to be extensive mold, and they wanted out of the contract.

When the homeowners found my website and called for advice, I suggested that they speak with their attorney and if they weren’t comfortable, to get a second opinion from an out-of-town real estate attorney, someone who would have no conflict of interest with local referral networks.

Why did I refer them to an attorney? because these sellers lost the sale of their house to individuals who had already signed a contract, all because a remediator pronounced the basement moldy without doing any tests. That is irresponsible and unethical. A remediator’s opinion, perhaps wrong, cost these homeowners their buyers.

I told the homeowner to take clear tape and touch it to the three spots. If nothing came off on the tape, it was likely that the spots were not mold. The homeowner called me back to report that they had held the tapes up to the light and “nothing came off.” Bingo.

The Mold Dog

I heard a similar story from a buyer who said they turned their back on their dream house after bringing in a mold dog who sat down in every room. They were afraid that the house was really contaminated.

Whoa. What does this mean, that the dog sits down? Maybe there was only a small, easily fixed, area with mold, and the gases spread throughout the house? Who knows? The point is that a very significant decision, and a very sad decision, was made by buyers with insufficient evidence. If I were the homeowners, I might have asked my attorney whether I could sue the mold inspector – and his dog.

Perhaps I am being unfair, and other testing was conducted which confirmed significant mold. But if not, to me, no tests were done for mold. What sort of disclosure is the seller supposed to give, that a dog sat down in every room? A mold dog can sound glitzy on the surface, but the experience of actually using one sounds like it can result in a lose-lose situation for both seller and buyer. From what this buyer told me on the phone, they made their decision based on the dog sitting down in every room.

Hopefully I have convinced you not to rely on a mold remediator or a dog to confirm that your home has mold.