Houses from Heck

Welcome to the premiere episode of The Indoor Environments Project, the podcast where we explore the evolving world of indoor air quality. 

In this debut, we’re joined by two industry rockstars: Joshua Kerber, Environmental Research Scientist with the Minnesota Department of Health, and Chad Robinson, founder of Building Performance Co., veteran mitigator and educator from Kansas State University’s Regional Radon Training Center. Together, they’ve seen it all—and they’re here to talk about the most outrageous, head-scratching, and humbling radon challenges of their careers.

🎧 We dig into:
 • “Problem houses” that defy diagnostics
 • How pros can build resilience, stay ethical, and keep learning

And in case you were wondering: yes, both Chad and Josh say their rig anthem is Don’t Stop Believin’. After hearing their stories, you’ll understand why.

Whether you’re a radon veteran or just getting started in the field, this episode brings a mix of humor, real talk, and practical wisdom that hits home.

The Indoor Environment Project is brought to you by the Indoor Environments Association—advancing science, policy, and professionalism in radon, vapor intrusion, and indoor air quality.

Transcript

Daisy: 0:00

This podcast is brought to you by the Indoor Environments Association, where science standards and community come together to improve the air we breathe and these spaces we live. To learn more and become a member, visit indoor environments.org. Enjoy the show.

Diane: 0:16

Welcome to episode one of the Indoor Environments Project, the podcast where we explore the spaces we live and the air we breathe. I'm your host, Diane Swecker, executive director of the Indoor Environments Association, and today we're diving into what we're calling houses from Heck, the kind of projects that test your pacience, your training, and sometimes even your sanity. This episode is packed with real world, great on mitigation, nightmares, unexpected challenges, lessons learned, and a few moments that might make you laugh, cringe, or totally rethink how you approach your next job. Joining us are two of the most respected voices in the field. Chad Robinson is the founder of Building Performance Company, a mechanical engineer by training and a nationally certified radon and vapor intrusion specialist. He's installed thousands of systems and currently trains the next generation of radon professionals at Kansas State University's Regional Radon Training Center. He's served in leadership roles both locally and nationally, including on the NRPP Certification Council and multiple standards committees. We're also joined by Joshua Kerber, environmental research scientist at the Minnesota Department of Health. Josh has more than two decades of experience in radon and indoor air quality with a background in atmospheric science and home construction. He's worked on everything from school testing and state licensing to international standards. He currently chairs the CRCPD's E 25 Committee on radon and has helped shape national and international policy on radon prevention. These two bring serious expertise and even better stories. let's get into it. Welcome Josh and Chad. So good. You can join us.

Josh: 1:55

Hello?

Chad: 1:56

Did I hear you say respected?

Diane: 1:58

Of course. Of course.

Josh: 2:00

Gosh.. We're not even 90 seconds in, and Chad already has to have some audio that needs to be cut par for the course.

Diane: 2:06

So we're gonna start off with some icebreakers though. Welcome guys. Appreciate you being here today. Our first question is, what's your go-to snack or drink on a long field day? That's an important question.

Chad: 2:19

Super important. You gotta fuel the mind and body. I'm a peanut butter and honey sandwich guy because on a hot summer day when that honey starts to crystallize in there, it's so good. Yeah, just that and water, that's my go-to.

Josh: 2:34

I don't necessarily have to eat or snack, I'll just work through, but if I don't have my diet Mountain Dew at the ready I don't know. The brain starts to shut down or go backwards.

Chad: 2:44

I think you're addicted.

Diane: 2:45

That's key. You do often see Josh Kerber with a Diet Mountain Dew.

Chad: 2:48

90% of the population is addicted to coffee. Josh is addicted to Diet Mountain Dew. Yes.

Josh: 2:54

It's cheaper than coffee.

Chad: 2:55

Yeah. Yeah.

Diane: 2:56

Okay, next question. If you are mitigation Rig had a theme song, what would it be?

Josh: 3:02

Don't stop believing.

Chad: 3:03

Don't, don't Stop Believing.

Diane: 3:04

Oh, that's good.

Josh: 3:05

Why Chad, why did you say that?

Chad: 3:07

There was this really great Uber ride at the symposium one year and the two of us and Bruce and a few other people were crammed into this Uber. And the guy's like, what do y'all want to hear? And everybody's just kind of sitting there. Bruce says Journey, it was one of the greatest car rides ever. Because these just blasting, don't stop believing in the car. It's kind of been this group of us, it's been our theme song ever since then. We've worked really hard over the last few years to, in the hopes that the radon industry would take a step forward in their technical capacity and professionalism. We've tried to encourage that in the industry. To me, that's what that song means is for us in that instance is we're not gonna stop believing that we can push that professionalism and technical expertise forward.

Josh: 4:04

That people may not follow too. Like the hope is that they're gonna be there to follow. But ultimately to me, to add onto that, it's don't stop believing the numbers you get. If you start to understand the building science and why you're taking measurements and getting these numbers. Believe the numbers and understand them and it will set you free from a mitigation standpoint.

Diane: 4:24

Yeah, that's great. What is the weirdest thing you've ever found in a crawl space or attic?

Chad: 4:29

We're in crawl spaces all the time. Probably 50% of the houses we work on have crawl spaces, so there's weird stuff in them all the time. Dead cats that are just skeletons now. Glass, always is glass in there. But there was this one house that had an addition that was a crawlspace and we pulled out a contractor trash bag full of beer cans and vodka bottles. And I suspect that's what just went in there as they were building that thing. Somehow it was still standing and I mean, it was built like 30 or 40 years ago too. I was impressed that, they were able to put away that much alcohol and still build a thing that still is standing to this day.

Diane: 5:12

Amazing.

Josh: 5:13

In my line of work though, I'm not in the field every day like, like Chad may be, so I get called out to the weird houses. I'm not in a whole lot of crawl spaces. I delegate that. But on inspections, oftentimes you do gotta get in crawl spaces. On one inspection, I found, the hard way a leaky toilet. The public health part of me was like, okay, I gotta clean up. But then also, obviously let the homeowner know what you found. 'cause I'm not there as a contractor. I'm there as a public health official. So that was one thing. I also found a ton of booze bottles in a homeowner's crawlspace. And no you do Chad on a daily basis when you find those things, but I inform the homeowner of what I find. And he tells me later that was the impetus of them talking with their kid about some alcohol abuse problems. And it was actually, a good thing in the end that I found that. Just doing normal public health work, just letting 'em know what I find. So that's more of a serious note, on a serious, yet funny note on an inspection, once I found Walmart shopping bags being used as poly to seal a crawlspace membrane.

Diane: 6:15

Wow.

Josh: 6:16

Yeah.

Chad: 6:17

Wow. What mill level do you think that is? Like 0.02? I

Josh: 6:21

don't even know. But yeah, it was super classy and it was right at the crawlspace entrance too. Nobody's gonna see it kind of thing. Right. It was ridiculous.

Diane: 6:30

I don't, that's a fine, that's a fine. I

Chad: 6:32

don't know if I've ever seen a Walmart bag that doesn't have a hole in it, let alone an entire crawlspace floor of bags that don't have holes in them.

Diane: 6:39

Exactly what I was thinking. Alright guys, so let's get into it. Let's kick off. So let's start off with the jobs that may haunt you.

Chad: 6:47

Yeah, and Diane, before we get into that, we maybe want to define what to us is a house from heck. We have in the industry have lovingly called houses that are difficult to fix houses from heck. In fact Daisy, had put a poll up on Nerds Facebook group and ask the question, what makes a difficult house to you? There was 25 respondents to that poll. One of the ones at the top of the list, like 16 of the 25 people said crawlspaces that don't have access. And it wasn't difficult to access. Or like inaccessible crawl spaces, like crawl spaces that are this tall. I say this tall and I'm showing you my hands and I forget that this is a podcast. You can't see that. But like you got six inches between the dirt and the floor joists. That's one scenario. That's tough. And sometimes, we could talk about that, but that's not what this podcast is about. But to me, and Josh and I have talked about this a lot, but to me, an inaccessible crawlspace does not make a house from heck. A client that is a pain in the butt doesn't make it a house from heck, a house that's a long ways away that you forgot to take the right size fan and pipe to, doesn't make it a house from heck. All those things make it difficult and you're losing money because of it, but it's not a house from heck. Your training hasn't necessarily taught you how to deal with the business side and maybe you lose some money, but that's not what we're referring to when we refer to a house from heck. To me, when we refer from to a house from heck, we're talking about one that has radon entry from a weird location or radon entry that doesn't happen consistently over time. So we have either radon coming in from somewhere other than where we normally think of it coming from, or it's coming in when we're not there to, see where it's coming in. Josh, I know you have some thoughts on this as well.

Josh: 8:36

Coming from the construction side of things, oftentimes hear I can't get suction to this far corner of the basement, and I always ask why. Because everything you're looking at when you go into a home is mostly lipstick and mascara. It's finished carpentry work, it's drywall, it's carpeting, it's some flooring that could be removed. You could do your work and then put it back. Now, are you gonna do that for your initial $1,200 bid? No, I understand that, but that also doesn't make it a house from, heck. You need to figure out a pipe route and finishing to wrap up a job. That's different than, I threw all my training and all of the expertise at this house, but it still has a radon problem at least some of the time, if not all of the time. And so then now those are the head scratchers that we talk about, that we refer to as a house from Heck.

Diane: 9:24

Those really difficult ones that kind of like you said, Josh, it's, you're left scratching your head.

Chad: 9:29

Yeah. You asked what is the one that haunts me? And I have to go to, the house we fondly refer to as Skipper. There's definitely people that will listen to this podcast that have heard about Skipper already. When we were working on this house, I called probably 10 or 15 different colleagues across the country looking for insights into what in the world could be going on. When we first got to this house, it's part of a real estate transaction. The buyers have not moved in yet, but the house has just sold. Radon levels are like 50 picocuries per liter. Normally those are the really easy houses to fix because there's a lot of permeability in the soil and we typically don't have a lot of permeability in the soil where we're at.

Josh: 10:12

Chad, where are you at when you're dealing with This home?

Chad: 10:15

We're right in the middle of Kansas.

Josh: 10:17

You're in the middle of what we'd call clay country. It's typically non-porous soils underneath your slabs.

Chad: 10:24

That's correct,

Josh: 10:25

yeah. Meaning clay or wet clay.

Chad: 10:28

Mm-hmm.

Josh: 10:28

IE expansive soils some people may call them.

Chad: 10:31

And we don't even backfill with gravel. We don't have any gravel close to where we're at, so we backfill with sand if we're lucky.

Josh: 10:40

In your area when you get blazing hot radon like 50, much higher than the four we're looking for obviously there's always some sort of air pocket because the house is drawing on something where it's on levels, in some pocket of air somewhere touching the foundation. You're not gonna get a lot of air flow through your substrates like you're, like we just mentioned. So there's something nearby that is always going to be the problem. Where is it? That's the issue you gotta figure out. And it may not be a big area, we may be only talking a, a couple of square feet. Right.

Chad: 11:15

Right. On this house, when we put the system in, I was really surprised that the soil under the house was. It wasn't even backfilled chunky sand or something. Every once in a while we'll have a river or sand that has a little bit of pea gravel. Occasionally we'll run across some pea gravel. Because this was 50 to start with, I expected, oh, we're gonna have some pea gravel and it must extend way out, away from the house somewhere or something like that. Because, or there's been a ton of settling somewhere. We didn't see any of that. The, there was no cracks in the foundations. This house was like, it was exactly the day it was built is, and it was built in 1963. To give everybody an idea, it's a rectangular, ranch house. 28 feet deep and 45 feet long, the standard ranch house that you see all the time. It has a 20 by 20 crawl space on the back of it. Off to the right side of the standard rectangle part of the ranch house, there's a single car garage. On the back entry into the crawl space, there is a patio that's sitting on top of the foundation wall, so a possible radon entry point there. The front patio is also sitting on top of the foundation wall. So a possible radon entry point there. We know that going into this. We know there's possible radon entry points. We're not really worried about it because typically they don't cause problems for us. Anyway, we get there, we put the system in, we've got good suction under almost all of the slab of the basement, and we've got great suction in the crawl space. We don't address the two patios or the garage at this point. There's one corner of the basement that we've got like a pascal of negative pressure when we have a pascal of positive pressure without the fan. So baseline pressure of a pascal of positive. So we have some driving force for radon to come in.

Josh: 12:58

In, in your baseline, you're getting positive one pascal, kind of everywhere in the basement. And so you're trying to beat that positive one Pascal, with your radon system. You put it in. You do your pressure field extension testing and it shows that you've got negative pressure anywhere where you're testing through the floor, right?

Chad: 13:16

The time that we're there,

Josh: 13:18

yes. Okay. So you should be winning the radon game if the radons coming from underneath the floor.

Chad: 13:23

Correct?

Josh: 13:23

Yep. Okay.

Chad: 13:24

And where are we winning the radon game? So we come back.

Josh: 13:27

Yeah, I was gonna ask, were you winning the radon game then at that point?

Chad: 13:29

When they did the original test, it was summertime. When we were there to put the radon system in to begin with, it was the beginning of November. The radon levels post mitigation were 150.

Josh: 13:41

Whoa.

Diane: 13:41

Yikes.

Josh: 13:41

In Kansas.

Chad: 13:42

In Kansas. I have never seen, well, only one other time have I ever seen 150. And that wasn't a consistent 150. This was consistent 150. So the previous one I'd seen, we'd have spikes to 150, but it didn't stay that high all the time. This is weird, right? In order for tight soils to allow enough air movement to get up to 150, that is just weird and mind blowing. I can't imagine how this is working. First thing I do is I verify PFE. Because that's what we've gotta do. Do we have PFE? Okay. Yeah.

Diane: 14:16

Hey Chad, can I, can I interrupt? Most of us know, but can you explain what PFE is?

Chad: 14:21

PFE is, an acronym for pressure field extension. It's an amount of suction that we have under the slab created because of the radon system. If we change the pressure relationship in the house from the positive pressure in the soil to having negative pressure in the soil relative to the house, then the air in the house wants to go into the soil rather than the soil air wanting come into the house. That's the basics of everything we do is can we make the soil air go into the, or the house, air go into the soil instead of allowing the soil air to come into the house.

Diane: 14:54

Got it.

Chad: 14:54

We're doing that at this house except for. We don't know what's happening under the front and back patio slab, we don't know what's happening under the garage slab, but we're done chasing the crawlspace and we're done chasing the basement slab. Except for we don't know over time that the basement slab is always staying negative pressure relative to in the basement.

Josh: 15:16

To clarify, you said you're done chasing those two foundations because you've tested it for your pressure field and you're showing negative pressure anytime you're there. In all four corners of the basement and the crawlspace, you got it pegged. You're good to go.

Chad: 15:28

Right?

Josh: 15:28

Presumably right. In the end, those numbers on the surface, on paper show good signs. But it's your radon monitor over the next 2, 3, 4 days that are really gonna tell you how you won the game or not.

Chad: 15:38

We always have to verify with the radon test, that's the most important thing. We're fixing the radon problem, right? We had negative pressure, like we want. Not fixing the radon problem. I'm not gonna put in another suction point in the basement until I know for sure that the basement is belching every once in a while or something like that. We get out a data logger, that logs the pressure in the floor. We run a radon test and a pressure test over time, and we can compare those two sets of data. We found out that we always have negative pressure in the floor we don't always have negative radon. In fact, the radon is consistently elevated. This goes on for a couple weeks, a couple of back and forths, and it's beginning of December by this point. It's cold all the time. Radon novels in this basement are now 250 plus. And we don't know how high it is because our radon monitors only go up to 250. It may be even a little worse than that. The weird thing was we had a radon monitor in the center of the basement. We actually had 13 radon monitors in this house. At one point we had a radon monitor in the crawlspace, six radon monitors spread out through the basement. We had radon monitors upstairs above the crawlspace, radon monitors in the bedrooms, a radon monitor in the garage, and absolutely nothing showed off.

Josh: 16:48

It gave, the radon was just the same, pretty much everywhere.

Chad: 16:51

It wasn't really the same everywhere. The center of the basement was the highest. But none of the corners where you would think. We know that we're controlling the floor. We know that we're controlling the crawl space, so it's radon has to be coming in through the walls somewhere.

Josh: 17:06

Right. And you've got poured walls in all your houses down there because they've gotta be structurally sound enough to hold back the water and the clay.

Chad: 17:14

Almost all houses are poured concrete, we're not dealing with block wall foundations that are porous and that kind of stuff.

Josh: 17:20

Yeah. You're not gonna have a whole ton of air coming through your walls at all.

Chad: 17:23

If we have radon coming through the walls, it's likely that it's an intentional penetration. Right. Like a sewer line that's been abandoned or something like that. That's the kind of things we were looking for was where's the sewer line that's been abandoned or the hole in the wall.

Josh: 17:40

You also talked about the adjacent slabs too. You haven't touched on how you explored those.

Chad: 17:45

Yeah, good point. One of the first things we did, around the same time period where we got the data logger out we also put temporary systems on the front patio, the back patio, and in the garage. We got negative pressure between the garage and the house. And actually the garage system made the negative pressure in the basement even more negative. It was going down the wall between the basement and the house and creating more negative pressure under the basement slab. And we were getting great negative pressure under the front patio and under the back patio. We've taken all of those things out of the picture. We don't need those temporary systems. They're not affecting the, those areas are not affecting the radon problem. So where's the radon coming from? We know that everywhere that we've tested, we've got negative pressure relative to the house. We don't need to touch that anymore. But there's something somewhere, there's a conduit that's coming from somewhere that's allowing radon, allowing soil gas into your house.

Josh: 18:41

There's a preferential pathway still unaddressed somehow. But where the heck is it?

Chad: 18:46

Yeah.

Diane: 18:46

Up until this point, you haven't seen anything that would indicate that you have a source there for that. Right?

Josh: 18:52

Right. Chad ruled out any sources that may be stored there, whether it be pottery paints glow in the dark radium watches, rock collections, that kind of thing. That's all been removed. And you kind of know it that's been removed too in the fact that the radon levels jump around. Where if you have an internal source in the ventilation rate of a house kind of stays the same, your radon level in that case would stay roughly the same. It wouldn't jump around like in this case it did.

Chad: 19:16

Yeah. One of the conversations I had was with Bill Broadhead, and he's like, I've had a similar scenario to what you had". He's like. This house, was built early on, and it had a septic sewer system. They abandoned the septic sewer system and went to city sewer. And they just cut the pipe off inside the house and it was just open to the septic sewer. The drainage field out in the yard was just pumping soil gas in through this hole in the wall. The difference is, I found a hotspot in the house and I knew that I needed to cut the wall open in that area. And the homeowner was let's go ahead and cut the wall open." The other thing that I haven't explained is: there's carpet on, 75% of the floor of this basement, and three quarters of the walls are drywalled and finished. Actually, let me take that back. 90% of the walls were drywalled. They ended up having a plumbing problem and they had to cut out drywall on one of the walls. I got to see inside the walls on a third of the walls. There's no plumbing pipes coming into the walls on that section. One other thing that it could be, again, something that Josh has reminded me about before is that if there was a well in this house, which is uncommon in our part of the country, but it happens occasionally. Then maybe it just didn't get covered up or capped off right and it's just letting radon come in. So I called the realtor and I was like, Hey, is there any way I could talk to the original owners of this house? And she's like, oh, they're older. Let me just give 'em a call and I'll ask if they had a well in there. She calls me back. Yeah, no, well, or any other plumbing situation or whatever. The homeowners did have a septic to begin with and they went to city sewer. After I talked to Bill, I explored that possibility forever and ended up finding absolutely nothing. I even stuck my sniffer down in the sewer clean out to see if there was high radon in the sewer. Nothing. It's less than ambient in the sewer. I'm okay, that's not what it is. I'm just scratching my head and. I ended up getting a Geiger counter from K State at one point from the radiation nuclear engineering department They loaned me a Geiger counter to see if any of the walls were hot somewhere. We're not gonna be able to see radon necessarily, but if there's a whole bunch of decay products plated out somewhere, maybe I'll be able to see some gamma coming through from that. Can't see anything. I scanned every inch of every wall and I'm not finding anything. I'm getting super frustrated. I actually have the radiation folks from the state of Kansas come out because I was like, these homeowners are gonna think that I'm absolutely incompetent at this point because I've been here for three months trying to figure this out. The state, radiation folks came out and it was awesome. For them to reassure the homeowners that we're doing the right thing. We're trying everything we can. They loaned me their $7,000 sniffer, which unfortunately never helped. But it was cool.

Josh: 22:14

Did it just tell you the same thing your own sniffer did, your much cheaper sniffer?

Chad: 22:18

More or less.

Josh: 22:19

So now how many gadgets are we at now? You're at a, you're at two sniffers, you're at a data logger, you're at all your different radon monitors, your 13 monitors your micro manometers.

Chad: 22:29

Yeah, probably four micro manometers. We've got what else?

Josh: 22:34

A ton detectors of one way or another. Pressure. Radon. Airflow.

Chad: 22:39

Yeah. There's also a company, they have made a device that's like an infrared camera for radiation. And I don't have the name of the company offhand, but they loaned me this device. I have no idea how much this thing costs, but they just mailed it to me and said, if you find the source because of this, it'll be good for us. And I was like, I really appreciate it and I will use it to see if I can find it. I left that there for several days and pointed it in different directions and left it set up for 24 hours as we moved around that house and tried to see if we could find any significant buildup of decay products. But the background was so high that it's just seeing radiation everywhere all the time. And it never found a source.

Josh: 23:21

Everything that you've had in your toolbox and all your friends' toolboxes have been thrown at this house. Yeah. It's still nothing, still no clear answers.

Chad: 23:31

And so.

Josh: 23:31

Until one thing happens...

Chad: 23:33

i'm talking to the homeowner at this point "I'm gonna have to cut open all of your walls and tear up all your carpet." And they're like, okay, if we need to do that, we'll do that." We were thinking about replacing the carpet anyway. They have a bunch of gun safes down there and that's gonna be the difficult part is to move the gun safes back off of the carpet. But we can make it happen if we need to. I know there's a conduit for radon somewhere and I'm not gonna just start putting suction points everywhere because it's not gonna help. We've already proved that all of the normal places aren't what's supplying the radon. One of the things that came outta the conversation with state of Kansas folks, was you have got to call the original owners of this house yourself. Yeah, you're right. I called the realtor back. I get the phone number for the people that own the house originally and get on the phone with the lady that built the house in 1963. She's still alive, and her mind is clear, as a bell. I asked her the first thing, "Is there a well in the basement by any chance? Or something like that. And she says, "oh yeah, there was a well in the basement 65 feet deep. We didn't have any water coming out of it, or not enough water, so we drill another well in the backyard." I said, wait a minute. I know about the one in the backyard, because I've stuck my sniffer in it and done all the things and tried to see if there's some way that there's radon getting from their end of the house. And she's yeah, that's the second well. I told you we had a first well in the house underneath the area where the water softener is." I was like, I've been all over the place... i've never lifted the brine tank on the water softener to see if it's underneath there. And I've had radon monitors in that area of the basement, right on top of the brine tank. And it came up less than in the middle of the house. I'm all confused. This is in the beginning of March, region seven has just happened. Josh came down for region seven and I was like, "Hey Josh, do you wanna go to this skipper house? On our way back to Salina", he's like, "yeah, I'd love to do that." I had just literally just found out that there was a well in this one corner of the basement. I go down there and I'm like, Josh, push the brine tank back. I'm gonna look underneath it and see if there's a well head under there. I stick my hand on the floor to balance myself to look underneath the brine tank. And there's air blowing on my hand, not from under the brine tank, but from the wall site. There's a wall right by the brine tank, and it's blowing from the wall. I'm confused and I'm like, Josh, I think I feel air blowing out from underneath this wall. He sticks his hand down there and he says, yeah, there's air blowing from out from underneath the wall. I get a knife or a scraper or something, I start messing around and there's all this rotten wood that I hadn't noticed before. I pick at it a little bit and it goes plunk. 65 feet down into the well hole, it's wide open underneath the wall, this well head. We eventually end up cutting out the wall and capping that and everything. When Josh and I were there, we were estimating that there was probably 10 CFM coming out of that wellhead just naturally, it was 1700 picocuries per liter in that well. That's enough to supply 255 PICOCURIES per liter to the entire basement of this house and 90 or a hundred picocuries per liter upstairs.

Josh: 26:40

Within 15 inches of that well head, you had a hole through the floor measuring pressure, field extension, and it showed that you had negative pressure.

Chad: 26:49

I did have negative pressure eight inches away from the wellhead, but not in the wellhead. I have like five pascals of negative pressure, which is enough for any season to fix the radon problem, but it doesn't, didn't go down into the wellhead. So we just capped the wellhead, applied suction to the wellhead radon problem goes away. We probably didn't have to do anything else to the entire house. But we didn't know it was there because it was buried underneath the wall.

Diane: 27:15

What challenge skipper was, for sure. How long was your whole time there from beginning to mitigation completion?

Chad: 27:22

Four months.

Josh: 27:23

And imagine the prior homeowner stayed in, lived in that house for 40 years,

Chad: 27:28

60 years. The house was built in 63.

Josh: 27:31

Wow. Wow. Wow.

Diane: 27:33

That's an. Amazing. I'm sure you don't have many like that, Chad, but boy, that was a, that was an adventure for you.

Chad: 27:38

I would be out of business if they were all like that. We know that wells are a problem. It's just finding the Well that was the problem.

Josh: 27:46

And more common construction nowadays that we don't have wells within the living structure of the building. They're outside, but all around the country, there are wells within the walls of the building. And if that's the case, that well shaft goes down dozens if not hundreds of feet into fractured earth, which is just a basic water filled cave. And if it's not full of water, it's full of soil gas. And those things can pump tons of radon in and out of the basement very quickly. And you just happen to find one or another one.

Diane: 28:21

And hidden pretty well.

Chad: 28:22

The takeaway from all of that is if we weren't doing diagnostics as part of this, if we didn't know what the suction pressures were, we would've just had to give up because there's no way we would've just put suction points all over the basement and had systems on the front patios and back patios and everything, and we would've never found the problem because we wouldn't know that, oh yeah, all this other extraneous stuff is not actually doing any good.

Josh: 28:47

That's a very common response though in the industry is that we're just gonna add a suction point in an area. We think where the radon might be coming in next, where you think it's coming in without actually verifying, is a foolish decision. 'cause you're just gonna be chasing your tail. You actually ruled out the fact that we don't need any more because we have it captured. There's something else going on. It's actually, it took a little bit more time, but it's a way less intrusive process in this regard, than just throwing arbitrarily suction point 2, 3, 4, or system two or three on a house. I cringe when I see more than one system on a single family home. It's usually never needed. But contractors will do it because they don't know any better. They're not confident in their ability to get the proper numbers.

all 3: 29:31

Right.

Diane: 29:31

Chad, you were very methodical going through it. If I were the homeowner, and how you explained it you checked every box that you had to go through. Every gadget was used. As a homeowner, you were the right guy to be there.

Chad: 29:42

We'd like to think so. And that's, that's honestly, that's the way the entire industry should be, is like we know what we're doing, we're professional about it. We're technical experts in the field that we're working in. And all of those tools in the toolbox are the things that we use to fix this problem. And it's not every house that has these kind of problems. But the ones that come up, if we can't fix 'em, then the homeowner's lose faith in our entire industry because they're like, "we had a house they just said it was too hard to fix." And that should never be the case.

Josh: 30:16

Yeah. It should never be the case. 'cause there's not a house we can't fix. The numbers will guide the decisions. If you apply the building science properly, you're gonna fix every house, period.

Daisy: 30:26

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Diane: 31:01

Really logical. Alright, what's next?

Josh: 31:03

There's handfuls of projects, I mentioned earlier in the podcast that, I don't get to see kind of the normal projects. Contractors call me when they run into problems like Chad called me. I get contractors locally that'll call Hey, I've got a difficult project. I've done X, Y, and Z. Can you come help me?" I don't see normal projects, like a drain tile system up and out. Real simple things. I see real complex houses, multiple foundations, giant houses, castles on lakes. I deal with clay soils, wet soils to sandy soils, to gravel soils, you name it. We have it all up here. When in this case it skipper Chad ran into kind of an airflow, a higher flow than he would normally expect to see. He deals with usually low airflow systems where I can deal with big airflow systems. Systems where we have pressure field extension almost all the time except when we don't. It's a whole different, our other side of the spectrum monster than what Chad could run into.

Chad: 32:01

Before you continue on that thought, you said I had a higher airflow situation than I normally would do you know how much air I had to move out of that well? In order to depressurize the Well.

Josh: 32:12

I do, you needed like 10 ccfm to properly capture that well. That's an additional 10 CFM that maybe the 15 you had in your other part of your system.

Chad: 32:22

It was higher flow. 'cause we had 25 cfm.

Josh: 32:25

Yeah. Versus your normal 15. Where common systems in my area twin Cities area of Minnesota. We're talking probably 40 CFM, give or take 20 either way. If we see stuff much lower than that, it's gonna be on expansive or tight. Clay soils, wet soils. However more than that, then we're dealing with higher airflow contributors, whether it's string tile with weeper tile, weeper hoses from concrete block walls, or geologic foundations either KARST which is a fractured limestone bedrock, that some of our houses get built on. Or glacial moraine, where the glaciers came in. And this isn't just centric to Minnesota, but anywhere where the glaciers from Canada came, dropped a bunch of stones and then retreated. Then the top of the year, those stones got overlaid by top soil, but underneath you had got a big air void of caverns. If you're driving around where I live and work, somewhere underneath you are big old cobbles, bigger than my head, which is hard to believe by some people. The problem then is you have to deal with a whole lot of airflow in order to fix a radon problem in some cases. You also have to deal with mother nature, more so than you would in tight soils. An example I have is actually an entire subdivision built with radon resistant new construction features. House after house built in the subdivision are built on hills. There's hills and valleys within the subdivision. And had one really proactive homeowner who had, done a bunch of radon tests and week to week it would fluctuate. No matter the season, she could get a high result and she could get a low result. She called me in and I turned her basement into a laboratory. It's a fairly modern house. In Minnesota, we got pretty strict energy code requirements, our houses are built tight, but ventilated right. In this case, I could get the indoor pressure in the house to 20 Pascals negative just by turning on the exhaust fans. The building, the outside structure is quite tight. They come tighter than that, but in this case it was about 20 pascals where I can actually just by triggering the fans that are commonly using the house. That's gonna induce a radon problem.

Chad: 34:27

You're talking about you turned on the bathroom fans, the fans fan over the range in the kitchen, the dryer.

Josh: 34:34

Yep.

Chad: 34:34

So all the exhaust fans in the house went 20 Pascals negative relative to outside or relative to the soil?

Josh: 34:41

Relative to outside.

Chad: 34:42

That is insane. That's half a blower or test worth of negative pressure just by the exhaust fans.

Josh: 34:49

I've actually seen houses that can do their own blower door test without the blower door. But in this case this house had all the radon resistant features that are required by building code. It's got the gravel layer, the poly vapor barrier, and then a three inch vent stack up through the roof connected to the drain tile in this case.

Chad: 35:06

So they don't need they don't need to do a radon test because they have a radon system.

Josh: 35:11

Au contraire. In fact, I wish it's another, another topic for another podcast is testing newly constructed homes. We gotta do it.

Chad: 35:19

Yes.

Josh: 35:19

Homeowner's concerned. I get there, drill probably eight to 10 holes on the floor to get pressure field numbers. And the day I was there, everything was great. Negative pressure in all four corners and the half walls in between, or should say midpoint the walls in between. Everything looks good, except I know that at some point it's not gonna be good because the continuous radon data shows me that for two days, three days, it's fine and then all of a sudden, bam, it spikes, and I don't mean spikes to five or 10, I mean spikes to 150, for a handful of hours and then drops back down to what, let's call it background again, and then bam, it spikes again in another three or four days. So I'm checking this out and I'm also data logging side by side with the radon data. Every time the radon spikes, I'm losing my pressure field extension in certain parts of the basement. And not just losing it, like going from positive or negative five to positive five. I'm going from like negative 20 to Positive 70.

Chad: 36:16

What?

Josh: 36:16

Yes. 70.

Diane: 36:18

That's pretty big.

Josh: 36:18

Yes. Hillside built house, and as the wind can suck and blow it can drive. I've measured these pressure changes. I've actually measured over time 150 Pascal pressure change just in one PFE location in a given home. We think we have robust systems installed, but we got nothing compared to what mother nature can throw at us sometimes.

Chad: 36:41

Just a second, Josh. Let's back up for a second because, you and I use Pascals for doing diagnostics in the floor. And there's a lot of people that will use inches of water column for diagnostics, or they don't do any diagnostics at all, and they just look at the U Tube manometer and they say, that's good enough. But 150 pascals would be like three quarters of an inch of water column. Right? You'd have to apply three quarters of an inch of water column to that spot. That's going 150 pascals positive in order to overcome that spike.

Josh: 37:13

That's right. So I've got an active construction system now that is getting overpowered by no mother nature. So what part of Mother Nature is it? I look at the wind from the local weather the weather stations, and I presented on this quite a few times, but you can, everywhere in the country, you can download the local climate data and you can see hour to hour weather data going back many years. As a weather dork, I know all this and I'm looking at it side by side. And it's not the wind or the wind direction that seems to be driving this. In this particular case, it's the atmospheric pressure and it's not the high pressure or the low pressure, it's when the pressure changes real drastically outside. So when storm fronts are rolling through and the barometric pressure is dropping. If it drops at a certain rate or worse, the radon will get sucked up by the atmosphere. It'll get sucked through the fairly hollow hillside and into these houses and at a clip that I cannot overcome with a three inch pipe, because the most airflow, I'm gonna move that three inch pipe, given the size of the pipe piping system is 60 or 70 CFM.

Chad: 38:17

Oh, come on, Josh. The fans are rated for 250 c fm.

Josh: 38:21

I know, but there's bottlenecks in these pipes, so I can't move anymore. So the solution here, given the criteria of multimillion dollar house, not gonna put a whole bunch of bigger pipes in all over. They switched from one three inch stack to two four inch stacks, and then a higher airflow fan. And I dropped the spikes from 120 for four to six hours, to now it spikes to maybe 10 picocuries for four to six hours when these super aggressive, low pressure centers roll through. But it's only in this correct case. I could predict when the radon would get super high without seeing the tape, just by looking at the atmospheric pressure trend over the last three days. If it dropped more than four milli bars over six hours, I'm gonna get a super high radon level. But if it just gradually drops, four millibars over 12 hours, the radon system can can actually handle that. So it's like the, kinda like a tsunami of air coming at that house, or the tsunami of radon coming at that house. If it all comes at once, I can't control it, but if it gradually comes, I can. But you're not gonna know that. Unless you're actually there or have something there to monitor the pressure or the radon all of the time.

Diane: 39:33

Josh, quick question. Going back, does your measurement device also measure barometric pressure and temperature or do you have specific devices for those measurements?

Josh: 39:41

I don't have specific devices for those measurements. Some continuous monitors do measure those things. I honestly don't put a lot of, credence in those numbers 'cause I just never double check them. And they're measuring atmospheric pressure and temperature in the device, not outside, which is actually more important. The temperature difference between inside and outside is more important than the temperature in the basement. And likewise they may be measuring atmospheric pressure in inches of mercury, which is a whole different ballgame than actually milli bars. Probably a more sophisticated device, which is why we rely on the weather service stuff that actually measured and verified rather than what's coming outta the monitors. But even if you were to look at if the monitor, some monitors will track that over time. You can see that at a sharp barometric pressure drop. If you're had a high airflow situation, you will see sometimes a spike in the amount of radon. And it works in inverse as well. So when the pressure rises really fast outside, that's the atmosphere, pushing the air back into the hillside and thereby pushing the radon out of the house. So you can see that too,

Chad: 40:42

I think this is interesting because it's something that we don't see very often. We don't see the atmospheric pressure spikes because we don't have a lot of available air in the soil. Now I always think of this situation where my kids and I were going skiing up in the. Colorado Mountains one year, and we're driving up this pass, it goes up to 10,000 feet and there's this chip bag in the back of the car where the kids are sitting and they're like, oh my goodness, this chip bag is going to explode because there's less atmosphere above, above us when we're going up the pass. The exact same thing is happening when the atmospheric pressure drops. It is going to expand that chip bag, not as much as driving up a mountain pass, right? But the air inside the hillside is wanting to expand. If the preferential pathway is into the house, where's that air going to go into the house?

Diane: 41:34

Makes sense.

Josh: 41:34

To finish a story about the chip bag. It did explode in the back of my car. I was hoping for chips to go everywhere you know, just like be this big explosion that just kind of popped and it was not very exciting.

Diane: 41:44

Not as dramatic.

Chad: 41:45

No. But if we took all of the air out of that chip bag before we went over the mountain pass, there just wouldn't be as much air to expand. If we had a vacuum sealed bag going over the of the mountain pass, it's not going to expand enough to be super visible. And that's what happens where we're at here in the middle of Kansas and most of the plane states, because we're working in really tight soils that don't have a lot of available air. We don't see that spike as commonly as you would in Minnesota or somewhere that has glacial Moraine or KARST geology.

Josh: 42:14

And KARST is actually more prevalent than a lot of people think. If you're on a river bluff. You're gonna have dissolved bedrock nearby, typically. So there are rivers in all of our states. We've got somewhere, you're gonna have higher air flows in small geographic locations. It's not completely homogenous everywhere in Kansas. But, a lot of Kansas is how Chad described it. But you're gonna have glacial Moraine and KARST in a lot of the upper Midwest, basically anything east of the Mississippi and say Tennessee North, you're gonna find a lot of it.

Chad: 42:43

There's KARST in Alabama.

Josh: 42:45

The Appalachians as well too. It's more prevalent than you think.

Chad: 42:48

We have KARST, geology in Manhattan Kansas South down through EL Dorado or somewhere in there that's the, what we call the Flint Hills. There's KARST there. I've worked on the edges of that geology in a different house that we had a well problem in. We did have a atmospheric pressure burp of radon into the house. But that had 175 foot deep well that went into one of those layers that had some openings in the soil, but typically close to the surface around us in the Flint Hills, there's clay packed into all the limestone in those hills. It's still pretty tight soils, but if you go deep enough, you can find some openings even in Kansas.

Diane: 43:28

Wow. That's great. We could go on and on about with these stories because they're really interesting and certainly these examples today have been pretty I would assume unique, but still just they're there and something for all of us to be aware of. As we close out here guys what would you say one common myth about tough mitigation is? What would you say to that?

Josh: 43:48

I have enough experience. I know what I'm doing, but I'm not doing pressure field extension. That's a common thing I hear. My experience tells me that I don't need to worry about radon on X location, and I ask, WHY? verify it. Too many contractors are not doing pressure field extension work, and that's really hurting the industry. Frankly! If everyone was doing pressure field extension work and understood what the numbers actually mean we would have far fewer system failures. We'd have far fewer oversized radon systems, costing millions more dollars to operate than we'd need. That's my biggest problem.

Chad: 44:24

The noise issue associated with larger oversized systems is a big concern. When I started, in the radon business, I was talking to a realtor at a house and she had to answer the phone and she said something about 'em here with the radon guy. The next thing I hear her say is, yeah, they're loud sometimes, but you get used to it. And I'm like, oh, if that's what people think, I'm gonna figure out a way to make sure that we don't have loud systems. It's very uncommon in houses that we need radon fan that's loud enough that it's gonna cause problems. They shouldn't have to get used to it. The common thing that I hear people say is if you still have high radon levels, you just need to move more air, put a bigger fan on and move more air. In the case that I talked about at Skipper, would moving more air have helped if it was in a random location or in the suction point that we already had in place? Absolutely not. And if we would've put a suction point in every corner of that basement and in the patios and in the garage, it would've done absolutely no good. Just moving more air.

Diane: 45:27

Go through what you had to go through. And it's, it's not necessarily always easy, you know, from your experience. Certainly, you all professionals do have that to draw from, but these examples, sometimes it takes a little extra time and a little extra work.

Josh: 45:40

It does. And the contractors shouldn't be running scared from these things. In fact, as a director, maybe you could have some input on this. The best experience some a contractor will get is just keeping with these difficult houses. And they'll get that experience and it's better than any CE class that they'll ever take. So if they can somehow come up with a presentation or paper, maybe you could award some additional CEs from your credentialing body. One other thing that I wanna really stress is there's a common misnomer nationwide, worldwide, frankly, where you pop a hole on a foundation and you see what type of soil is there that shall dictate the type of radon fan you use. And that is simply untrue. Just because Chad runs into clay soils does not mean he uses high suction radon fans. High suction radon fans are expensive to start with and they're loud, and just by him sucking harder in the north corner of a basement doesn't mean he's going to get better PFE in the south corner. The better way to get PFE in that south corner is a second suction point and using a smaller radon fan, if that piece of intellect was industry wide, we would be so much better. The substrate should not dictate the type of fan you use your numbers from your PFE analysis should dictate that fan you use.

Diane: 46:57

Great information.

Chad: 46:58

The thing that i've heard w ay too often people say, I look at my u tube when I'm done putting the radon system in. And if it's below a certain amount, then I feel pretty confident that we're gonna fix the radon problem in this house. That might be lower just because you have a bunch of pipe above the fan. Because if you have resistance above the fan, the differential is going to go down. That is not an indicator of success. I don't know where people get that idea that, oh, hey, we have to have our U Tube be below 1.8 or 1.5 or something like that with a mid-range fan to have success. It's not about that at all. Can we measure the pressures in the floor everywhere and do we have negative pressures in the floor relative to inside the house?

Josh: 47:44

Chad, to wrap up, you live in clay country. You work in clay country. When was the last time you used a high suction fan in a single family residence?

Chad: 47:52

I've been in the radon business for over 15 years, and it was probably 12 or 13 years ago, maybe longer than that.

Josh: 47:59

So the common notion would say that you should be running high suction fans every job, and you simply don't. Because you know better.

Chad: 48:05

And actually, if we have a good preferential pathways in the soil, we use low pressure fans.

Josh: 48:12

Meaning low flow or low wattage fans. Right?

Chad: 48:16

A low wattage fan, like a RN one Spirit or RP one 40, that we use those 30 to 40% of the time in clay soils.

Diane: 48:27

Huh. Wow. Josh, Chad, thank you both for being here and for kicking off this podcast, the stories that are both surprising and really insightful. If you wanna carry on this conversation with Chad and Josh, please join us in Fort Worth this year, in October, we will, be meeting for our annual radon and VI symposium. Should be a really informative and fun event. So check out our website to get more information on that. For our listeners, if this episode made you nod your head or laugh a little, don't forget to subscribe. Share it with your team and send us your house from Heck Stories. We might feature one on a future episode. Breathe easy and keep doing the good work. Thanks! Take care everyone.

Daisy: 49:07

That’s it for this episode of The Indoor Environment Project. If you enjoyed the conversation, learned something new, or just felt seen by the stories—we’d love it if you subscribed, shared this episode with your team, or left us a review. Want to go deeper? Join the Indoor Environments Association and be part of the movement to improve the spaces we live and the air we breathe. Membership gives you access to a national network of pros, discounts, standards, CE courses, and so much more. Visit indoorenvironments.org to join today. And don’t forget to follow us on social media for updates, insights, and real-world stories from the field—we're on LinkedIn, Instagram, and Facebook.