How to Test Your Home for Mold, with Mike Schrantz

Mike is the mold inspector that I had inspect my home and my office for mold and helped identify some issues that we were having there that I’ve mentioned in a couple of emails and elsewhere, so I thought it would be really helpful to have Mike come on the show and talk about some of the myths and truths when it comes to testing for mold and also share a little bit of my experience, what I went through, as an illustration of how complicated and murky things can get when you dive into this world and then finish up with some tips for how to find a qualified and dependable indoor environmental professional, which is what they call this profession, in your area.

In this episode, we cover:

4:16  What industrial hygienists do
8:35  Common myths about testing for mold
20:02  Chris’ personal experience with mold
46:02  Where to start if your house needs inspecting

Chris Kresser: Hey, everybody. Welcome to another episode of Revolution Health Radio. Sorry I’ve been absent for the past few weeks. There’s a ton going on for me. We recently moved, which I’m going to talk a little bit about in this episode actually. Launch of my clinician training program, ADAPT Practitioner Training Program, from the Kresser Institute happened earlier in January. Suffice to say, it’s been a busy time, but we’re going to get back on a fairly normal schedule pretty soon, and we’re going to kick things off with an interview with Mike Schrantz from Environmental Analytics.

Mike is the mold inspector that I had inspect my home and my office for mold and helped identify some issues that we were having there that I’ve mentioned in a couple of emails and elsewhere, so I thought it would be really helpful to have Mike come on the show and talk about some of the myths and truths when it comes to testing for mold and also share a little bit of my experience, what I went through, as an illustration of how complicated and murky things can get when you dive into this world and then finish up with some tips for how to find a qualified and dependable indoor environmental professional, which is what they call this profession, in your area.

A little bit more about Mike, to begin with: Mike currently owns and operates Environmental Analytics, LLC, an environmental consulting firm. They’ve been in business since September 2007 and have worked with a number of large clients in the Southwest. Mike is based in Tucson. Previously Mike worked with a large residential heating and air conditioning company, Russett Southwest Corporation, where he led the indoor air quality department.

I met Mike through the Surviving Mold community. That’s Dr. Ritchie Shoemaker’s group. I had Dr. Shoemaker on the podcast a while back to talk about the health implications of exposure to mold and other indoor biotoxins and the related syndrome called chronic inflammatory response syndrome. I’m part of a group of clinicians that talks about the health implications there, and we also have indoor environmental professionals in that group that are looking at this from a building science perspective. Mike is part of that group, and that’s how I encountered him. Then, as I said, I had him come out and inspect our home and office. He’s really knowledgeable and open minded, which I think is crucial in this world, and I’m looking forward to talking to him about the proper way to do mold inspection in a building.

All right, let’s dive in.

Mike, thanks so much for being here.

Mike Schrantz: Thank you very much for having me, Dr. Kresser.

What Industrial Hygienists Do

Chris Kresser: Let’s start by talking a little bit about exactly what an indoor environmental professional is because I think there’s probably a substantial number of people in my audience who have never even heard of that and have no idea that there is a profession out there like yours of people who are essentially the equivalent to what I do with the body for a building.

Mike Schrantz: Yeah, that’s correct. We’ve come by many names in the industry. I think industrial hygienist is a word that perhaps a few more of your listeners may be familiar with, but like anything else, there are niches, and the term indoor environmental professional certainly covers a wide range of concerns in the environment. It doesn’t necessarily just have to be about mold. It can be odors, it can be bacteria, it can be radon, but I think the focus for those listening is that if you’re an indoor environmental professional, you’re somebody that’s focusing on the built environment as it is and you’re trying to find a way to either detect a problem or to improve an environment, making it healthier for the individuals.

Chris Kresser: I am kind of struck by the similarities between what I do as a functional medicine practitioner and what you do with buildings. For me, when a patient comes to see me for the first time, they have a number of complaints, but it’s my job to link those complaints to deeper physiological processes that are out of whack that explain why those things are happening in the first place. I imagine for you it’s kind of similar. If someone says, “Oh, this room stinks!” or “I feel terrible since I moved into this house,” and they have some symptoms or things that are bothering them, it’s your job to walk into that house and kind of almost look at it like an individual and try to figure out what’s going on there.

Mike Schrantz: I think you’ve nailed it on the head. We run into a lot of cases with clients where our job being that we are looking for typically a contaminant, whatever it may be at the time, they want us to be able to say if it’s safe in the home or if it’s not safe. It’s an interesting dynamic because our job really isn’t to tell you whether or not a specific contaminant is safe for you specifically. We can certainly give you guidelines and kind of an overview, but our job is to be a doctor of the home. It’s your job as an actual doctor to diagnose health, and so this is kind of a newer frontier for a lot of us, where we’re trying to create relationships between the indoor environmental professionals who can bring the knowledge to the home and about the home and then somehow create a relationship that’s symbiotic with the doctors so that we can learn from both of us. For example, if you were to tell us that there are certain symptoms that your patient is having, that may help us try to focus on a particular type of contaminant over another.

Chris Kresser: You’re kind of like Dr. House for an actual house!

Mike Schrantz: That is correct. You could call it that if you want to!

Chris Kresser: For everyone—full disclosure here—I met Mike through a group that I participate in. I had Dr. Shoemaker on the podcast a while back, which I’m sure a lot of you listened to, and it’s a particular approach towards dealing with chronic inflammatory response syndrome, a condition that’s caused by exposure to biotoxins in the indoor environment. In this group, there are not only physicians and other healthcare practitioners that are looking at it from the healthcare side of things, but then there are also a number of indoor environmental professionals that are exploring the same issues via a building assessment perspective, and that’s how I came across Mike.

We’re going to spend the rest of the interview talking about the ins and outs of getting your home or building assessed for mold and other biotoxins, but we’re going to talk about it through the lens of my own experience because, as many of you know, I’ve been dealing with mold and mold-related health issues myself and with my family for the past several months, which is one of the reasons why the podcast has kind of been on a little bit of a hiatus lately. We just moved house actually, literally two nights ago. We just spent our second night in the new house last night.

Commons Myths about Testing for Mold

I want to begin by maybe dispelling some common myths about testing for mold and other biotoxins in the indoor environment, and then I want to kind of just go through my experience, which Mike has been with me for every step of the way because actually Mike was the one who did all of the inspections for me for our previous home and our new home and also my office where I see patients. I figured it would be really instructive for me to share my experience because it’s been sort of a comedy of… not a comedy of errors in the sense that anyone made any mistakes, but just a whole bunch of stuff that could go wrong did go wrong, and I learned a lot in the process, and I think it would be a really useful example for all of you of just how murky and complex this stuff can get and just how inadequate some of the conventional approaches are because they don’t really take this complexity into account.

Let’s start, Mike, by talking about some common myths. I’m going to toss a couple your way and let you go to town on them.

Mike Schrantz: You got it.

Chris Kresser: Idea number one: Let’s say I want to get my house tested for mold. I contact a local company, and they send someone out. They do a walkthrough of the house, and then they do what’s called a direct exam air sample. They set up the air sampling device on a tripod, and they take a little air sample, and then that’s the end of the inspection. That’s probably—at least what I can gather from talking to my patients and doing my own investigation before I hooked up with you—what about 80 percent of mold testing outfits are doing these days. What’s the problem with that approach?

Mike Schrantz: I wish we had eight hours to talk.

Chris Kresser: I know. It’s abbreviated.

Mike Schrantz: But I’ll try to get to the bullet points of everything.

Air sampling is limited. We’ll focus on mold, and Chris can direct me other ways if he needs to, but when we’re talking about mold, not all molds behave the same, first of all. What I mean by that is not all of them float in the air as much. Some are heavier. Some are lighter. Some settle out quicker. Some are dry. Some are sticky. And when you collect an air sample, especially the way that you’ve described, direct exam—and you’re right; you say 80 percent. Man, I’d be willing to bet even higher that a lot of these companies that call themselves mold testing companies will go out and collect an air sample.

The problem is, with that type of sampling, it’s not that it’s a worthless sample; it’s just that it’s so limited in what it can tell you because it’s what we like to refer to as a “grab sample.” It only collects about 5 minutes’ worth of air. We’ll put it into a volume here: 75 liters. That’s about 2.64 cubic feet of air. You don’t have to be a mathematician to know that the amount of air that that represents in any given environment—say, a bedroom, for example, let alone the whole house—is very, very small, and it has a small capture rate. So you could have something going on in the home, and this air sample may not be able to pick it up, or what may be impacting you is predominantly on the surfaces. They do get kicked up from time to time, but it’s not going to be picked up with a tripod with a portable pump on there.

So what ends up happening is a lot of customers will get their results back, it’ll show no problem—and I say that interpretation loosely—and then the customer will call us up because their doctor will say, “Well, your blood work doesn’t correlate with that. It’s showing that you do have a problem.” They’ll end up having us come in and do some more forensic types of tests, and then sure enough, we find a problem. So air sampling by itself is seldom enough. Usually you want to incorporate some other techniques to add to that.

Chris Kresser: Right, and then there’s the issue that we’ve talked about many times, which is that some types of mold are heavier than others. When you have a heavy mold like that, it’s not necessarily going to stay airborne for very long, and it might settle down onto the surface.

Mike Schrantz: Yeah. Take, for example—we’ll just pick on it because it gets a lot of attention; it’s not the only mold to be concerned about, but a lot of people know about it—the mold Stachybotrys chartarum. That mold is referred to as a lot of things, sometimes incorrectly online, but black mold or black toxic mold.

Chris Kresser: Right.

Mike Schrantz: It does deserve some attention, but it’s not the only mold that’s out there. The point I’m trying to make is that it is a heavier mold, and so it’s not unusual to seldom see those levels show up at all, Stachybotrys, in an air sample. And if you do see it, it may only be, like, one or two or three raw counts that are identified. In other words, put simply, it may not show up as a “problem” on that air sample, but in fact, you do have a “problem” in the house.

Chris Kresser: Right.

Mike Schrantz: Air samples just by themselves don’t really offer enough data. There are other things we can do to improve the data we collect that will offer a much better picture of what’s going on.

Chris Kresser: OK, so this takes us to the next one. Let’s say I’m a customer, someone who wants to have my house inspected. I suspect I may have health problems with mold, and then I’ve heard about this other kind of test. I know enough to know that air sampling on its own is limited in its potential. Not to say that it’s useless. I think folks have gone a little too far in the other direction as far as that goes, but I know it’s limited, so then I’ve heard about this other kind of test called ERMI, where you sample dust off of surfaces or use a vacuum to collect dust, and then you send that in and it’s a DNA test. What’s the problem with just that? Can I just do one of those and wait for the results and then call it a day once I get them back?

Mike Schrantz: A couple of considerations when taking an ERMI sample, and for those are wondering, that’s environmental relative moldiness index. We can talk more later, if we have time, about kind of how that came about to be and all that, but basically it is a DNA-based test. The situation we’re running into with that test, and there are a few of them, but the big one we’re dealing with right now is the quality of the lab that you use. There are some labs, and I’m not here to talk today about don’t use this lab, don’t use this lab. I can tell you labs that I do prefer, but they use what’s called a primer and a probe when they basically pull apart and grab the DNA from these samples that you collect from that surface sample you described. And believe it or not, these primers and probes have different qualities. Some are low quality, and some are high quality.

Some of the labs that try to save money will use those low-quality primers and probes, and what ends up happening to the end user is that you think you’re saving 20, 30, 40 bucks by using this lab, but really what you’re getting is bad data because what we’re starting to see is a trend of these lower-quality primers and probes producing lower counts than what’s actually present. In other words, you’re getting a false negative. People are going, “Look, there’s no problem here,” and then you can do a side-by-side comparison with another lab that uses a higher quality, and all of a sudden it paints a totally different picture. It will start identifying stuff that was there but it just wasn’t picked up. So you don’t just send your sample to any old lab that says they can do it. You need to try to find out which labs are producing the best results for the money.

Chris Kresser: Right. So we know the lab is important, and we want to choose a lab that is using the EPA-validated approach because that’s the one that has been studied. Just for listeners, this is identical to what we talk about with lab testing in functional medicine. If there’s a lab out there that’s doing its own thing, has come up with its own methodology, and that methodology has never been peer reviewed and never been validated and replicated by an independent third party that has no financial interest in that particular test approach, then we can’t really rely on the results. It’s the same thing with the ERMI test.

Mike is not mentioning any names, but I can tell you that I feel very confident with Mycometrics. That’s the lab that we send all of our samples to with our patients that we recommend. It’s the lab I’ve used myself in my own testing.

Mike Schrantz: Great lab, Chris. Great lab.

Chris Kresser: Yeah. So if you’re going to do it, you have to do it right. That’s the thing. I’ve learned that over and over again throughout this whole process. When you’re dealing with mold and potential for other biotoxins, you don’t want to cut corners because it’s just too important when you’re talking about your own health and your family’s health. Believe me, I’m not insensitive to the expense involved in this stuff because it’s considerable, but at the end of the day, spending 25 percent less for a test that’s not going to have results that you can rely on doesn’t make any sense. You might as well not do it.

Mike Schrantz: You’ll spend thousands of dollars chasing a ghost, so get it right the first time.

Chris Kresser: Right. So we’re using Mycometrics, and we’re going to do an ERMI. Can we just do one ERMI in the house and take a composite—take some dust from one room, take some dust from another room, take some dust from all the different rooms—and then send that in? Can we just rely on that as a conclusive word for whether there’s mold in the house?

Mike Schrantz: It was all good until you said the word “conclusive.” I’ll give you a couple of different thoughts here, and again, given my background and with the doctors like yourself that we’re working with, you really are coming up with this relationship of what works best for the patient and also the data you’re going to get and when. It’s a timing thing.

So here’s the scenario I’ll paint for you. A lot of patients, their doctors will have them actually collect their own ERMI sample. Usually the reason that we primarily get for that in the beginning stages is that it’s a cost thing. Even if a patient collects their own ERMI sample done by Mycometrics, for example, you’re going to spend somewhere between $325 and $350 by the time you get done shipping it and all that stuff to get an analysis. That’s a great starting point, and a lot of people will do a composite sample throughout the home to give you an idea—and remember that word “idea”—of whether or not you really have a potential mold problem, something that shouldn’t be in your house. The problem that we’re getting with that is, what happens if you do? Or what happens if the results come back and they’re in that gray area, meaning it’s not really showing an obvious problem, but if the results were just a little bit better, I’d sleep easier at night. Well, believe it or not, those gray area results seem to pop up a lot more than the good or the bad because the ERMI is an index. It’s not meant to be perfect. It’s meant to give an idea.

So without a doubt, to go to your question, a lot of times, no, a single ERMI sample from us, from the professionals collecting it, is not going to be enough. Usually you’ll dissect the home into a couple of areas, and we’ll even collect an outdoor one as well to get a better idea of what the true impact that the outdoors is creating versus whether or not it’s coming from an indoor source.

Chris’ Personal Experience with Mold

Chris Kresser: All right, so I think this is a good segue into talking about my own experience. Let’s focus on the new house because I think that kind of has almost everything that we need to talk about. Maybe not everything, but it’s a good illustration.

Mike Schrantz: Unfortunately, but yes.

Chris Kresser: Yeah. Listeners, here’s just a little brief background. We recently bought a house because the house we were living in previously, we suspected, may have an issue. The testing we did there was equivocal, but I have the blood markers, and our daughter has the blood markers for it, and I was concerned enough that I wanted to just get into an environment where I had complete control over the environment and could make whatever changes I needed to make. We had been thinking about buying a house for a while, so I thought this was the thing that would push us over the edge to do that.

So we found a house. It was actually on the same street as our current house, not a big move. We looked at it, and it wasn’t possible to have a comprehensive inspection for mold before we bought the house, for a number of reasons that I won’t go into right now, so we bought it and it had the typical house inspection that said that it was free of mold.

Mike, maybe you could say a few things about that. I imagine those inspections that are associated with house purchases are even more limited than having a full assessment.

Mike Schrantz: Yeah, I guess it depends on what day of the week it is you catch me on. “Limited” is a nice word.

Chris Kresser: Right!

Mike Schrantz: They’re limited. If you even get any sort of sampling, you’ll probably get air sampling.

Chris Kresser: Yeah.

Mike Schrantz: Again, it’s not that if you’re not one of those 24 percenters that are especially mold sensitive or don’t have the ability to rid toxins, that kind of a thing, it doesn’t mean that if you’re a 76 percenter that you’re OK. It doesn’t mean that you can’t get impacted, and the problem is that a lot of home inspectors, their limit of knowledge is what they learn from a two- or three-day course from a mold class.

Chris Kresser: Right.

Mike Schrantz: So they’re going to go out there and they’re going to look, and visually if they don’t see anything black on the wall, growing, they’re going to tell you, “I don’t see a mold problem,” but clearly, in your case, the new home, that’s the furthest thing from the truth.

Chris Kresser: Yeah, exactly. There was no visible mold, and even just on doing a more thorough inspection, there weren’t any areas that were just obvious problem areas where you could see water damage or moisture intrusion or anything like that. But because I am treating a lot of this in my patients and I have concern for my daughter and my own health, I wanted to have Mike come out and do a thorough inspection. So Mike came out and did that, and why don’t you tell us a little bit about what we found initially, Mike.

Mike Schrantz: Sure. To go back to the question before and then right into that question, you had asked about whether or not collecting one sample is enough. We like to collect more than one sample because it provides us more contrast. We can create smaller zones in the house. For example, with yours, there’s a small upper-floor section. Then you have your main floor below. So we separated out the house into actually some different areas. If I remember correctly, the upper floor was one sample. The lower floor, I think the kitchen and the living room—or maybe it was just the kitchen—was one zone, and then we separated out another section of the lower floor, and we did that based off of the layout of the home, any suspicions we had, and we did it with ERMI sampling. Then we collected an additional sample outside called a control, if you will, to really compare and get an idea of whether or not some of these molds that affect your ERMI score may have been coming from the inside of the house or from, in fact, the outside.

The short version, the less dramatic version, of the results was that the upper floor looked like there was no issue whatsoever, but the lower floor had a few suspicious levels of mold and types of mold that made us wonder whether or not there was a potential source in a few areas. I think the segue to the next section was that we had recommended a few areas be inspected visually under containment by a remediation company, a local company, to see what they found, and I think they found some stuff!

Chris Kresser: Yeah, exactly! There are a couple of things I want to emphasize there. One is the need for a control sample. Mike mentioned that, and it’s really, again, a similar idea to a control in a clinical trial in medicine. If you’re looking at what’s happening inside of a building, you want to know what’s going on outside of the building because no building is going to be completely sealed off, hermetically sealed from the exterior. There’s going to be some communication between indoor and outdoor spaces, and if you see higher levels of a mold, for example, indoors that is also very elevated outdoors, then you might suspect that that’s a problem with exterior communication into the interior space. But if you see high levels of a mold indoors that’s not well represented outdoors, particularly if it’s a mold that’s associated with water damage, then you might be looking at more of a moisture problem inside.

Now, I’m not trying to step on your toes here, Mike. I just wanted to clarify a couple of things for the listeners because this is something that we came back to over and over again in our house.

Mike Schrantz: Not to interrupt you, but to complement that—and I’m actually glad you brought that up because it would have been brought up by a couple of listeners—the ERMI does have what we call group one and group 1 and group 2 molds, and the group 1’s are the water damage-related type molds. Group 2 is kind of categorized as common fungal species. It’s not that they can’t grow when there’s been a water damage event inside your home. It’s just that it’s more about them showing a level of communication between the inside and the outside.

But keep in mind that the ERMI is an index. It is a scoring system that really is blind to each house by house. It’s kind of just basing what it thinks based off of an average of a little over a thousand homes that were used in the study to create ERMI. In other words, it does already kind of take into consideration to a small degree the outdoor influence, but not to the level that having an indoor environmental professional takes it into. And when you’re working with an indoor environmental professional, ideally it would be nice for them to consider what the outside influence is from some of those other molds because at the end of the day, whether or not your doctor cares whether that mold is coming from the inside or outside, as an environmental professional, it’s critical that we figure out what the source is and where it’s coming from because it absolutely has all the difference in effect on what recommendations we make.

Chris Kresser: Right. That’s so important.

OK, so we saw some evidence that there might be a mold issue, but we didn’t have enough data just from the ERMI QPCR dust samples, which is more the name of the technology. ERMI is kind of the name of the analysis that happens, right?

Mike Schrantz: Correct. Technically the analysis method is QPCR, qualitative polymerase chain reaction—there will be a quiz later—but the analysis, the interpretation of the data, is called ERMI.

Chris Kresser: Right. We loosely refer to it as ERMI. It’s not technically correct, but now you know the difference. It’s easier than saying QPCR every time.

OK, so we knew there was an issue, and that was slightly disappointing, having just paid what we paid for our new house here in the Bay Area, but we had to look further because my goal in this whole process was to create what I’m calling a mold sanctuary. There’s no way to 100 percent guarantee that you won’t have a mold issue, but I want to get as close to that as possible with this house, without razing it to the ground and starting from scratch.

The next step was to try to figure out where the mold was and what was causing it. My wife had noticed during a rain that the front of our house, the way it’s designed—it’s an old Cape Cod-style house—there’s no overhang on the roof, and not only that, there’s no awning over the front door. With the prevailing direction of the wind and the rain, the water would blow right into the front door and just go right down the front door and pool at the doorstep. That was one area that we thought might be affected by water maybe getting into the house or into the wall there somehow. And then we also wanted to do further investigation in the kitchen because the kitchen was the area where the ERMI results were a little bit elevated.

What we did was we had a local remediation company come out, put up a containment, which means they seal off that particular area from the rest of the house so if there is mold, it won’t communicate to other parts of the house. Then they did what are called cavity samples, so, Mike, maybe you could talk more about what those are.

Mike Schrantz: Sure. A lot of times, like any technician or professional, they have tools in their toolbox, so to speak, and one tool that I actually use on a regular basis is a wall cavity or cavity sample. What it is is you may have an area, say, an exterior wall, that’s suspected to have been contacted by moisture, water, something, and ultimately the concern is, hey, maybe there’s mold growth in that cavity. Ultimately the concern from that is, well, can it communicate into the environment? And the assumption is, yes, based off the building science.

So what we’ll usually do with wall cavities is we will drill a hole about 3/8-inch wide in diameter and allow access for a tube to hook to a cassette that air is then drawn through, and we sample that cavity. It really is kind of like an air sample, but we’re using it differently. I know we were talking down on air samples not too long ago, but in a confined space like a cavity, they’re actually ideal because what you’re looking for when you drill that hole in the wall cavity is to see if there’s mold growth. One way to do that is when you drill a hole, when you put that tube through there, if the wall is disturbed and there is mold in there, it will pick up that mold on the cassette. You send it off to a lab, the lab interprets what’s on the cassette, and then we’re able to read from that and determine whether or not there appears to be microbial mold contamination in that cavity that you sampled.

Chris Kresser: Right, so we did these cavity samples, and in the kitchen there was a slightly elevated spore count, and the area near the front door, on one side of the door, if I recall, there was an elevated spore count. Then we knew we had to do even more investigation. The next step after this is to take off a piece of the wall while the area is still in containment to see if there’s visible mold in the wall cavity. So we did that on both sides of the front door—also disconcerting once you’ve just bought a new house, to start ripping pieces of the wall off, but that’s how it had to be!

Mike Schrantz: You had a great attitude.

Chris Kresser: We ripped the wall off, and then under the sink, which is where the count was a little elevated in the kitchen, we took off the back panel of the sink and had that investigated. But during this process, there was a period of three or four days or very heavy rains, and just being over at the house after three days of those rains, my wife and I were standing in a downstairs bedroom and noticed that the wall was kind of buckling out a little bit to the bottom right of the window. I put my hand on it, and I could feel that it was even a little bit damp, and it was a little bit squishy when I touched it, and I was like, uh-oh.

Mike Schrantz: Yeah.

Chris Kresser: This is an example that we did all the fancy testing, and Mike had done a very careful visual inspection when he was out here, but it hadn’t started raining yet when Mike was here, and so there was nothing visually that you could see at that time. But then after the three days of rain, what had happened is the window was leaking.

Mike Schrantz: And to your listeners, by the way, you could imagine the phone calls and the emails I got from a concerned Chris, wondering what was going on.

Chris Kresser: Yeah! The window was leaking into the wall. Water was getting into the drywall, and as Mike would tell you, drywall is a perfect medium for mold growth. So then we had to put that area under containment, and the guys took off a piece of that wall under the window, and sure enough, they found mold there. But they saw that the mold was continuing beyond the little piece of the wall that they had taken off. This is where the remediation company plays the game that they call “follow the mold.”

Mike Schrantz: Yeah.

Chris Kresser: They basically have to keep removing the wall until the mold stops, and even then, it’s typically recommended to go a little bit further so they’re sure that they got the end of it. They continued removing wall, and it was actually going up the wall, and they ended up removing the entire wall on the west side of the house, above the window, and saw that there was mold above the window, so then that was a question mark because obviously windows don’t leak up. Gravity takes care of that. So the explanation of the window being leaky wasn’t sufficient to describe why there was mold above the window.

The remediation guy that I was working with—and maybe that’s a future podcast—we were there during a rain, and he said, “Let’s go take a look at the gutters.” So it’s pouring rain. Some of you who live in the Bay Area know how hard it can rain here. We were standing out in this pouring rain on ladders, climbing up and looking in the gutter, and when we look in the gutter, we see that it is completely full, almost to the point of overflowing, with standing water.

This gutter was very old. I think the house was built in the ‘20s, again, a Cape Cod-style house, and back then, for this style of house, at least, they would build the gutters into the actual structure of the house. It’s made of redwood, it’s hollowed out like a canoe, and it was part of the structure of the house.What had happened was two things. Number one, the gutters hadn’t been cleaned regularly, and so they were full of debris, which was preventing the water from draining. And number two, the flashing between the gutter and the house that would prevent any water from getting from the gutter into the house had broken down. So what was happening was the gutter was filling up, was not draining properly, and water was overflowing actually right into the wall of the house.

When we were looking at the inside of the wall, we could actually see little rivulets of water going down the siding of the house once we had taken off the wall. And when Bill, the remediation guy I was working with, was on the ladder and he cleared the gutter and the water drained through the downspout, the little rivulets of water stopped, so we actually got visual confirmation that that was what was causing the entry of water into that section of the wall.

Finally, after a lot of testing, we had figured out what was causing the mold problem that we found, and this is what I want to emphasize. In all of the testing that we did, the testing just pointed to a problem, but the place that ended up being the most significant issue was something that was not identified with any of the previous testing and that we actually found by good old fashioned visual observation.

Mike Schrantz: Yeah, it’s hard to ignore, and I do mean that. It’s hard to ignore that testing that by itself doesn’t always cut it. We can save this for a little bit later so you can finish where you’re going, but I will say that visual is, in some parts of this, just as important, dare I say slightly more important, than data itself. You can’t take away from what you guys found after the fact and that our sampling wasn’t pointing at that location at the time we collected the sample.

Chris Kresser: Yeah. This is not a static process. I think that’s the other thing I learned. You don’t just inspect once and that’s the end of it.

Mike Schrantz: Correct.

Chris Kresser: Mike was there, he inspected, and it was fine. And then after the rains, it was not fine.

Mike Schrantz: And you know what? We could have come back after the rains, change a few variables to your story, and maybe we had found something, but I guess it’s a dynamic process and you always have to be paying attention.

Chris Kresser: Exactly. Unfortunately, this was not the end of the story, though!

Mike Schrantz: No.

Chris Kresser: We’re just getting started. No, we’re not just getting started, but we’re about halfway through. The next step was we found the mold, they did an extensive remediation process to get rid of the mold, and then they do a cleaning process afterwards, which involves damp wipes and things like HEPA vacuums—we’re not going to get into it—and then you have to do a retest, of course, to make sure you have clearance, the mold has been dealt with, and you can move on to putting your house back together after you’ve just pulled the walls off.

So we did the first retest and got back the results and were quite shocked to see that actually the numbers were still pretty elevated. Mike got a lot of text messages and emails from me about that, too, like, “What the heck is going on here?!” It was very distressing, of course, and we at that time were basically held up from moving in and proceeding by the mold issue and the lack of clearance, so it was definitely a stressful time. But a local company helped with the testing, because Mike is in Arizona and I’m in California, so we hooked up with a local company that was really helpful in the retesting process, so I didn’t have to fly Mike back and forth for every retest. The guy who did the retesting, he said when he walked into the containment area that it smelled moldy. There was a distinct smell.

That’s another thing that I want to point out: You have to trust your senses in this process, and whether it’s something you’re looking at, or, Mike, I’ve heard you say it, I’ve heard other people say if you smell a mildewy, moldy smell, that’s enough, right? That’s enough to know that you need further investigation.

Mike Schrantz: Yeah, especially on a clearance test, and that’s what the gentleman was performing that day for you, was a clearance test. When he goes in there and the first thing he gets is a musty smell, it’s not starting off well.

Chris Kresser: Right. We got a musty smell, so we did the retest. The retesting failed. So then the next step was to figure out what was going on here. It was extensively cleaned. The visible mold was remediated. Was it communicating from a different place? From outside? Without going into detail, it’s an old house, there were some vent holes in the siding, and there was kind of a hole at the bottom of the wall cavity that was kind of going into a subfloor area, and so we thought that might be part of what was causing the problem. So we had all those areas taped up, sealed off and cleaned again, and then we decided to take off a few sections of the other wall because the gutter wraps around the house. The whole wall that we took off was the wall that was underneath the rain gutter that I had mentioned was a problem, but the gutter kind of wraps around the house, so we decided to take part of the wall off underneath that section of the gutter.

Mike Schrantz: Not to interrupt, but just before you say that part right there, I think, just for the listeners, the reason why we had made that judgment call was you’re this far into it at this point. Chris and his wife and, I’m sure, his whole family were hanging by a thread in terms of their state of mind on all this. We got to the point where we were like, let’s just go slightly further than maybe what we would normally do because we’re tired of it failing, recleaned, failing. Let’s get to the point where let’s just cover all of our bases, and then cue Chris on what we found.

Chris Kresser: Right. When we removed that wall, sure enough, we found more mold actually, top to bottom under the wall because that was actually the part of the gutter that was right near the downspout. So when it had backed up, it was overflowing into that section of the wall as well. To an extent, it was a relief to find that because it explained why the retest had failed. It wasn’t something that was just nebulous. So then we had to do more remediation of that section of the wall and then a cleaning and then another retest.

We did the second retest, and I thought, “Great!” I started making plans to get the contractors in there to rebuild the house, and I hired the moving company, set the move date, and we got the second retest results back—fail again. You can start to imagine the texts and emails Mike got after that one! That was a big question mark. We had a lot of conversations, and as it turned out, the remediation company I worked with was great, I think they did a fantastic job overall, but we suspected that they may not have done the best possible job cleaning before that second retest, after they remediated that second section of the wall. The reason we thought that was that the person who did the retest noticed that there was a lot more dust than he would have expected after a cleaning.

So we had them come back in and do a final cleaning, which was very thorough and extensive, and we got the third retest results back, and I did a dance through the house and was ecstatic that we got passing results. Most of the molds were listed as non-detectable. There was one mold where there were something like 25, I think, if I recall, Mike?

Mike Schrantz: Yeah, 25 or 26.

Chris Kresser: Yeah, Penicillium, but this was another example of where the outdoor control can be really helpful because the mold that was a little bit elevated, it is an indicator mold that can be a sign of water damage, but it was extremely high in the outdoor sample, so the most likely scenario there was just that there was some communication from outdoor to indoor, whether it was that the person doing the testing had it on their shoes or some other tiny little gap that couldn’t be sealed. Mold, it’s tiny, tiny, tiny, and it can get through lots of little spaces that you wouldn’t imagine that it could get through.

Mike Schrantz: I’ll tell you from 800 miles away, from where I live to where you live, it was really stressful. I’m certainly not trying to put myself in your shoes because you were the one living it and experiencing it, but it was frustrating because boots on the ground are key. Having that professional to be there is key, and I wasn’t able to be that role in this particular situation for the entire project. I can tell you that I think both of us—I know you said earlier—we both learned a few good lessons, not just for our own project and what we experienced, but also to help people in the future to try to minimize that so they don’t have to go through the same… is “nightmare” too strong a word?

Chris Kresser: No. I think that’s accurate!

Mike Schrantz: Yeah, it was an experience.

Chris Kresser: It was an experience. To some extent, I’ll look at back at this and… I’m still a little too close to it to look at it with 100 percent gratitude and appreciation.

Mike Schrantz: Right.

Chris Kresser: But certainly through my own experience with chronic illness, everything that I learned in that process, I’ve been able to use that as kind of grist for the mill in a way that I can help other people, and I know that this experience with mold will be a similar one to that, both on the health side—everything I’ve learned in my own experience with it and treating patients—but also now from the building science perspective. I mean, I know now a lot more about building science than I ever thought I would in my life, and it’s actually fascinating. I’m thinking about a career change, Mike.

Mike Schrantz: Oh, you’re welcome!

Chris Kresser: Just kidding. But there are a lot of similarities. You walk into a building, and you kind of have to go through a similar process to figure out what’s going on that I do when I’m working up a new patient, so I appreciate that aspect of it. And as a homeowner and a father and husband, I like having a much clearer understanding of how to create a safe environment for my family, and I definitely have that now.

Mike Schrantz: Absolutely.

Where to Start If Your House Needs Inspecting

Chris Kresser: Let’s wrap up by… I know a lot of people, after listening to this, are going to feel like, “Wow, I think I might be dealing with mold.” They’ve read some of my articles or listened to my podcast. They’re concerned about their own family, and they know they want to have their house inspected, but they don’t know what to do because maybe they call up a company locally, and they ask them what they do, and they say, “We do a direct examination air sample and a visual inspection.” Admittedly, I wish we had an answer for all you listeners, some referral service that could cover every part of the country, where we could hook you up with someone who knows exactly what they’re doing and is looking at things at this level of detail and depth, but maybe we could give a few tips, Mike, for at least what questions to ask or what people can look for in a local inspector, and then we can talk about some options for even getting someone who’s not local, like I did with you.

Mike Schrantz: Sure, absolutely. Again, it’s too much to cover in one sitting, but just know that one of the things I can offer you guys right off the bat, those of you who are interested or in need can always reach out to me via email. Chris can provide you with that contact information, and I can give you that time. I think that’s the first trait, actually, you want to look for in a professional—a professional who will give you the time. Anybody who you’re going to call up and who sounds like they only have a minute to talk to you, it’s probably a sign that they don’t have the capacity to handle your situation. These things take time. I don’t mean years, I don’t even mean months or weeks, but this is not an a la carte package. There are companies like Lowe’s and Home Depot that sell these mold petri dish test kits.

Chris Kresser: Right.

Mike Schrantz: This is not that simple. This is not a do-it-yourself problem, as you’ve heard from even Chris’ experience with a professional—albeit I wasn’t there the entire time—but even with Chris’ own knowledge base, it didn’t go as smoothly as it could have, let alone trying to do it on your own. So find a professional who is willing to give you the time and who is open minded. What I mean by that is use your reasonable rationale, use that common sense, and if it sounds like the inspector is giving you one-way answers that really don’t have a lot of reasoning or rationale behind them, that should be a yellow flag for you.

Another thing to watch out for is any mold professional who tries to act like a doctor. It is not my job to determine whether or not something or a contaminant can affect your health, so if I’m sitting there telling you that something can, it may be a yellow flag for you to go, “Why are you making those calls?” because those types of calls can impact the type of tests they do on you. In other words, they may not put your needs first at hand.

In terms of sources, places to go to look, there’s an organization, the ACAC.org. You can type it in. I’m actually doing it right now to make sure their site is good to go. ACAC is American Council for Accredited Certification, and basically they have a “Find Certificants” tab in the center on the top. You can type in your zip code, and it’ll pull up a list of people in your area that have certain credentials. To save those listeners some time, you’re looking for somebody who has a certification like a CCIEC, that’s council-certified indoor environmental consultant; somebody with a CMI, that’s a council-certified microbial inspector; or they have CMC, which is a consultant. That’s where you can start. You want to look those people up, see in your area.

In terms of things to look for, interview questions to ask them, certainly fee structure, but again, there should be a minimum fee, but we really don’t know, as environmental professionals, what exactly we’re going to test until we get out to your home. It should be a red flag for you if someone is giving you an out-the-door price and you’ve only talked to them for 45 seconds on the phone and they’ve never visited your home in the past. They need to be able to go out there and do a site assessment. Clearly, Chris has a great example of what the power of a visual observation can do for you.

Have them walk the property. You may or may not get them to crawl through your crawl space, and if they do, they may charge you a little bit extra. I really don’t blame them, to be honest with you. It’s not that fun. But they’re going to look on the outside. They’re going to look for things that are obvious areas where water may breach through. They may have moisture detectors or infrared cameras that look for signs of moisture intrusions on the outside or the inside. You want to talk to the inspector about, once they identify those things, how that correlates with sampling. If they’re asking you questions of if you have any health symptoms and what they are and they explain to you the differences between, say, for example, direct examination-type sampling versus ERMI sampling, which we talked about earlier, that’s a good sign.

At the end of the day, we can’t provide you with a list of questions to ask a person that’s going to guarantee that you’re going to get the ideal setup, so to get you started, I would take advantage of the comments and the direction I have given you, but always know that you can always reach out to professionals like myself. There are a few of us, and we’re more than happy to look up somebody in your area and see if we can get you in communication with those professionals, because at the end of the day, these certifications are minimums. They’re what I would call the minimum requirement to get their foot in your door, but it’s not necessarily going to be a guarantee that they’re going to give you the most comprehensive job that you would want. There are so many different disciplines in indoor air quality and environmental professionals that you may have a professional come out there who is an expert in radon, but that’s not exactly what we’re talking about right now, is it? Take the time to ask the questions. What is your background? What do you know about mold? What can you tell me?

Then go to places like SurvivingMold.com. Go to places like my website, EnvironmentalAnalytics.net, and look up and see if what they’re saying is consistent with what we know about mold. Then I would say start from there, and always know that you always have an extra resource, like I’ve mentioned a couple of times now, with myself. I’m happy to help you out.

Chris Kresser: That’s really generous, Mike, and I would definitely take Mike up on that. He has been extremely helpful to me throughout this entire process. I don’t know what we would have done without him. I know for some of you, you may just want to cut to the chase and have Mike come out and do your home as well, and I wouldn’t blame you for that because it’s a real minefield and a Pandora’s box. It’s another one of these areas where there’s a lot of controversy. There are polarized arguments and heated debates. It’s difficult for a consumer, a person, a patient, who just wants to find out if they have an issue in their house, and they don’t want to get involved in all of the philosophical debates and get embroiled in that. For me, that’s kind of why I decided to hire Mike and have him come out. I just felt comfortable with his approach. He was open minded and not really dogmatic like some people can be, and the stakes were so high for me and my family that I needed to have complete trust in the person that was doing the investigation.

Wherever you are, if you have someone locally that you feel confident in, that’s awesome. That’s obviously way more convenient, and it will be cheaper. If you feel like you’re in pretty dire need for help and you can’t find anyone locally, then I wouldn’t hesitate to look Mike up through his website, EnvironmentalAnalytics.net. You can also go to Surviving Mold and search through some of the resources there.

At the end of the day, the key thing is to just stick with it. It can be pretty harrowing, as my experience probably has let on a little bit. You didn’t get the intensity of the emotion that I went through over that experience in this podcast because I’m mostly through it at this point, but it was intense. It was really challenging in a lot of different ways and stressful and frustrating and maddening at times, but now that we’re through it and the walls are back up and getting painted today, I just now feel so good. We slept in the house the first night on Saturday night, and I put my daughter Sylvie to bed just knowing that she was going to breathe easily and wake up the next morning not being congested and having the symptoms that she had before when she was exposed to mold. I mean, there’s really nothing I wouldn’t do for that peace of mind.

Mike Schrantz: Absolutely.

Chris Kresser: Mike, thanks so much for taking the time to do this. I hope all you listeners got something out of this. I really appreciate your generosity and commitment to this, Mike. It’s really evident in your work with us and how you operate in this world.

Mike Schrantz: Having an opportunity to be able to share my knowledge and experience and help others is a true privilege. I appreciate the opportunity, Chris.

Chris Kresser: Great. Take care and maybe if you have a moment or two, come by the blog post and answer a few questions from folks. I certainly don’t expect anything voluminous, but I know there are going to be some questions, and just even pointing people in the right direction or a couple of places might be helpful.

Mike Schrantz: I sure will. I’m happy to do that.

Chris Kresser: All right. Take care, Mike.

Mike Schrantz: Thanks. You too, Chris.