Robin Jade Conde

PODCAST: Radon, Radon, and Radon (with Josh Kerber)

Today, Josh Kerber from the Minnesota Department of Health will talk about radon gas. He is a research scientist who does applied research in building construction, specifically with indoor air.    

Tessa checks the statistics of existing vs newly constructed homes that have radon. Reuben clarifies the action level to which one is encouraged to do something to fix it. While Bill confirms the licensure requirement for proper radon testing and installment of mitigation systems. Josh shares that 45% of Minnesota homes will have elevated levels of radon and the various safe levels that are identified by WHO, USA, and Canada. Further, he shares about the Radon Awareness Act. They also discuss the common defects in the installed radon mitigation systems and the alarm system that is required in the state. 

Reuben shares a technical question about where to terminate the radon height and the need to have radon fans installed outside of the house. Josh shares the historical background where radon came to fruition.

Reuben extends appreciation for the feedback raised, especially from homeowners. He assures them that the podcast format will be retained. However, there will be episodes that are home inspector-focused.



The following is a transcription from an audio recording. Although the transcription is largely accurate, in some cases it may be slightly incomplete or contain minor inaccuracies due to inaudible passages or transcription errors.


Bill Oelrich: Yeah, personally, I’m not skeptical of Radon, but I think there are some older people who might be a little bit skeptical, so we’re gonna peel back the onion here and learn a lot about Radon.




BO: Welcome everyone. You’re listening to Structure Talk, a Structure Tech presentation. My name is Bill Oelrich, alongside Tessa Murray and Reuben Saltzman, as always, your three-legged stool, coming to you from the Northland, talking all things houses, and anything else that pops into our mind on a given day. We’ve been away for a couple of weeks. Reuben, you held down the fort last week, but now the whole team is back in place and we’re very excited for today’s episode. We’re gonna be talking with Josh Kerber, who is with the State of Minnesota, the Department of Health, technically. He’s a Technical Radon Lead with Minnesota Department of Health, and he’s a research scientist, and Josh knows everything there is to know about Radon, so we’re gonna put him on the spot and we’re gonna ask him 67,000 questions about Radon. So, I’m really excited because it’s this one topic that I think… Personally, I’m not skeptical of Radon, but I think there are some older people who might be a little bit skeptical, so we’re gonna peel back the onion here and learn a lot about Radon, but before we get to Josh, we gotta circle back to the end of our last episode where we put a call to action out to our audience to ask them what they thought we should do moving forward with the podcast.


BO: Should we look to be just speaking to home inspectors or should we continue talking to people who own houses, who sell houses, who inspect houses, and for the explanation of all the responses, I’m gonna turn to you, Reuben, please tell us what the audience is suggesting we do.


Reuben Saltzman: Sure, yeah. As soon as we made that request, we got a flood of emails and my assumption was that it’s just about all home inspectors listening to this podcast, but as it turns out, they’re just the vocal group. [laughter] There’s actually a lot of homeowners who listen to this podcast. I said, “If you listen and you’re a homeowner, just drop me a line, and I got a lot of lines.” There are a ton of homeowners who listen to this, so I just wanna take a quick second and thank a few people for writing in. I wanna thank Kathy, John, Robert, Jodie, Scott, Andrew, Scott, John, John, Michelle, Joel, Nathan, Emily, and Brynn, and Andrew, and Andrew, and Damon, and Paul. [laughter] Thank you all for sharing your two cents with us. I read all of your emails and I really appreciate you taking the time, so you are heard and we will not be changing the format of this podcast. We may occasionally dig into some topics that are more home inspector focused, and we’ll be announcing those at the beginning of the show, we’ll kinda say, “Hey look, today’s show is more focused for home inspectors, we’re gonna be talking about this topic,” and if people wanna tune out for that week, cool and home inspectors’ ears may perk up a little bit more for those, but we’re not going to be significantly changing the format of the show, so I’ll just throw that out there right away.


BO: That sound you just heard was me wiping my brow ’cause I was sweating a little bit about having to get super technical about things. [laughter] Probably not the place I belong.


TM: I wish people could see your face right now, Bill. [chuckle] Relief.


BO: Yes, relief. Relief. Well, with that said, I’m excited to be moving forward with this conversation about Radon, so Josh, can you take a second and introduce yourself to everybody and correct any mistakes I made in my introduction, but kinda tell us who you are and how you got in the position you’re in and what you do on a daily basis? 


Joshua Kerber: Alright, well, thanks for the invite, you guys. I’ve been watching and listening as a fan and reading blogs for long time. My name’s Joshua Kerber, I’m with the Minnesota Department of Health. I’m a research scientist, do a lot of applied research of building construction, specifically with indoor air and even more specifically, Radon gas. I cut my teeth doing Radon-related work, and we, well, in the 2000s, so I’ve been at this for 21 years. You wouldn’t guess it, looking by baby face, I guess, but I got a degree in atmospheric science, and then prior to that, I was in the home construction business. My father is a ceramic tile and stone installer, so worked alongside a lot of different trades throughout the years. Got a job with the Health Department in 2002 to run General Education and Outreach regarding Radon to the general population in Minnesota.


JK: So we’re out pounding the pavements, saying, “Test your home, Radon causes lung cancer,” and all the other warnings that you’re probably likely aware of, in doing so too, I got mentored by some of the best building scientists around and learned a lot about Radon mitigation, and now I’m a lead of sorts in the state, in our region and in the country, as far as helping increase technical capacity, both from state and tribal Radon programs as well as contractors, co-trainers with Kansas State University, where we help train really advanced techniques for proper system sizing, which is important, and hopefully we’ll get into some of that too, so I really like the technical aspects of my job where I can go look at the house with the contractor who’s having trouble, suggest some recommendations, point out why it’s not working, or why it’s probably working too well, and maybe dial some of this power, the suction or air flow back, and every time I do that, we come up with a case study or something to share with the rest of the world so everyone else can learn what we learn. Hopefully these difficult-to-fix houses become somewhat something of the past where Radon mitigators just really kinda know how to handle all these different situations, but as you guys are aware, every house you walk into is a different situation.


BO: So where do you share these case studies? Do you do a blog or a YouTube channel, or do you teach this stuff in person? How does that get distributed? 


JK: Well, prior to COVID, we would host in-person trainings for our Radon partners, we’ll call them, whether they were our licensees, our local nonprofit folks, where I would just present case studies and the information. Other places, since COVID, we’ve been doing a lot of free webinars through our office, broadcasting live from the south metro in the bunker, and then also at national and regional Radon training conferences. We do a lot of that stuff there as well.


BO: Okay. So Josh, let me ask you, do you do any other business besides this? Do you have a side business where you do any Radon mitigation or testing or any of that, or is it exclusively for the state? 


JK: Yeah. Exclusively for the state with the exception of I’m a consultant trainer for this advanced technique with Kansas State, but other than that, no, this is really just what I do for the state.


BO: Okay.


TM: Hey, I’ve got a quick question before we dive into the really technical stuff, Josh, can you say why people should be concerned about Radon and what it is for people that are listening and may not really be familiar with it at all? 


JK: Absolutely! I get so wrapped up and just assuming everyone knows what this all is, right? Radon is a natural occurring radioactive gas that’s found in virtually any soil in the Upper Midwest and through a lot of soils throughout the country. It’s a leading cause of lung cancer for non-smokers, it’s the second leading cause of lung cancer overall. The latest EPA risk estimate puts about 21,000 premature lung cancer deaths each year in the United States. So, it’s bad stuff. We can’t see it, we can’t taste it, we can’t smell it. The only way to know if you have in your house is to test, and so that’s why we suggest every house gets tested. Every house is a little different, operated a little differently so that’s why we should test more, that’s a redirect to our Radon web page, and there’s probably too much information on that web.


TM: Why would it be the… You said Upper Midwest and then some other southern states. Why Upper Midwest? 


JK: We can blame Canada.




BO: That’s too bad. I like Canada a lot.




JK: Canada also has a pretty high Radon too. It’s got, for whatever reason, it’s got a lot of Uranium and Radon in it. And as the glaciers came and scoured and pushed that dirt, they left it here for us. So we have Radon in almost every soil type, wherever you look. We assume that Radon is basically everywhere in the dirt, it’s a matter of how much. So as glaciers receded, the dirt was left behind. We now build boxes and live in these boxes and work in these boxes, and those boxes, even though we think that they’re well-ventilated, and they are, in many cases, they run negative but they suck on the soil, and so that’s how Radon gets in and we can get into that a little bit more too.


RS: I got a question. While you’re bringing up Canada, makes me think of something I’ve heard. I’ve never actually done my own research on this, but I heard a rumor that the action level, the level of which we say, “Hey, this is too much Radon and you’re really encouraged to do something to fix it,” I’ve heard that the action level is way higher in Canada. They’re way more cool with having a bunch of Radon in their houses. Is that true? 


JK: Sort of.


RS: Okay.


JK: The Canadian reference level is higher than the United States action level. US action level is four picocuries per liter, and understand that that action level was not health-based, it’s technology-based line in the sand that EPA drew in the 1980s based on technology of a building science at the time. So that’s kind of where the industry “safe level” is. There’s no safe level of Radon at all.


RS: Okay.


JK: In fact, many lung cancers attributed to Radon occur in homes that are less than four, so we wanna get it as low as we reasonably can. Now, up until the early 2000s, Canada’s reference level was somewhere around 30 picocuries for residences. They have since lowered that, and I’d actually have to go back and get the exact number. I wanna say it’s somewhere around 8 picocuries but don’t hold my feet to the fire on that.


RS: We will not.


JK: But if they lowered it, it’s not as low as ours. In addition, World Health Organization has come out with a standard reference level of 2.7. It’s a conversion from what they use as Becquerel per cubic meter. They said, “Let’s set it at 100,” and so the international community outside of the United States is like, “Okay, yeah, that calculates down at 2.7.” So you’re gonna see three numbers in writing. You’re gonna see before, that EPA set, the 2.7 from the World Health Organization, and then EPA also, when they set a level of four they said, “Consider lowering your Radon if it’s over two.” So it’s like a consideration, a pretty hard recommendation for four, and then 2.7 is, again, the World reference, standard reference tool.


RS: Got it! That’s helpful.


BO: Josh, I have a question, because in Minnesota, we have gone through a licensing event in our state, so can you talk a little bit about why licensing was brought up here with some of the things that happened, who is actually under the purview of this licensing doctrine or what, however you wanna call it? Just give us some background on licensing.


JK: Alright, I’ll try not to take the whole rest of the podcast to do that. It all started with, back in 2012 or 2013, we offered up a legislative solution to get more Radon education out, and what the Governor and the Health Department proposed was what was called The Radon Awareness Act. And in short, what that required is during a home sale, the seller is required to disclose anything that they know about Radon on the property. Have they tested, do you have the documentation if you have done so, have you taken any steps to reduce it and do you have that documentation, and then finally, two other things, there’s a Radon warning statement. It’s a two-paragraph statement that’s required language in the disclosure statements that says basically Radon causes lung cancer. It can be tested for and fixed. You’re now made aware that Radon might be a problem in this property you’re about to buy. What you do with that information is up to the buyer. Do they wanna test for it? Do they wanna negotiate it? That’s all up to them, optional kinda thing. You’re not required to test or mitigate. Well, when that was promulgated, January 1st of 2014, we overnight saw a fourfold increase in the amount of mitigations being installed.


TM: Okay.


JK: So a big increase in Radon awareness and really driven, mostly driven by real estate, and the industry really is driven by real estate to different varying degrees.


JK: Well, with the additional mitigations, estimated eight-fold increase in the amount of Radon tests being done. Some of those tests weren’t being done properly, some of the mitigations systems weren’t being installed properly, so then in comes the complaints, so a couple of years later, the legislature says, “Well, we have to nip this in the bud too,” and so they proposed regulations on the Radon professionals in the state, and that went through a couple of different iterations over a few years. There was an injunction. It’s all been adjudicated, so now that the dust is clear, if you’re doing the Radon test in a building you don’t own or lease, you have to have a license through our department. If you’re gonna do mitigation in a building that you don’t own or lease, you’re required to have a license through our department. Laboratories that analyze Radon test kits, there’s not many of them, but they’re required to have a license through our department, and then companies with multiple licensees for mitigation are also required to have a license through our department.


JK: The other addition to that is that each mitigation system installed in Minnesota is required to have a Radon mitigation system tag. It’s a unique four-inch by six-inch tag that’s affixed to the systems, when the systems are completed and finalized, let’s just say, or commissioned, maybe in your guys’s work.


BO: I wanna press you for some details on one of these items. You said like, “If you’re a home owner,” I’m making sure I’m getting this right, let’s say I’m a homeowner and I wanna install a Radon mitigation system at my own house, I still need to pull a permit for that right? 


JK: No, actually. So if it’s in your own home, you’re free to do the work.


BO: Got it.


JK: Similar to plumbing, electrical… Now, electrical is gonna require you to get a permit and an inspection. You guys would know more about the plumbing aspect of stuff, common sense telling me it should still be inspected, but they don’t have to have a license to do the work if it’s in your own home. Similar to, per this particular regulation, if you’re doing it in your own home, the regulations don’t apply.


BO: So that’s really interesting, because the way all the rest of the building codes are written is that if you’re doing permitted work, it doesn’t matter who’s doing it, whether you’re licensed or not, permitted work requires a permit. Period. And if you’re the homeowner, you get special status where you don’t have to have a license to pull that permit, and you can do it on your own single family home that you own and occupy, but you’re saying with Radon, not only do you not need to be licensed to do the work, but you don’t even need to pull a tag if it’s your own house. I’m I getting that right? 


JK: Yeah, that’s right. I’m not saying that that would be the best way to write the regulation or the statute, the legislator wrote the statute, but we’re left with applying it to professionals and to the state for that matter.


BO: Okay, that’s a very interesting point. Alright, now let me propose something crazy. Josh, what if there was a company out there who promoted and installed sub-slab dehumidification systems, this is not Radon mitigation, this is just something that looks and talks and smells just like a Radon system, it’s a pipe that goes underneath your basement slab, but instead of having a pipe up through the roof, they just wanna go out the rim joist, they wanna go out the side of the house, and it’s not there, remember, to mitigate Radon, it’s just there to remove moisture from underneath your home, to kinda dry out your basement.


JK: Or whatever else it might be under the floor.


BO: Yeah.


JK: Right? 


BO: Yeah, and if some Radon gas were to be mitigated, so be it, how would you guys treat that? 


JK: Well, if it’s unscrupulous, you’re gonna get found out. There’s a lot of self-policing that we’re hearing too. So people calling and saying… Well, first of all, I’m not gonna say that this is a big problem that we see. We’ve heard of the hypothetical, and what would we do? So, in short, how would we handle that? What is that system there for? Was there a Radon test conducted prior to that thing being installed? If the answer is yes, then that is a Radon system. If the answer is no, then really, why is it there? If it’s not there for Radon, can we really regulate it, would we really regulate it? It’s kind of a gray area that hasn’t… It hasn’t come up yet. Now, we have had companies that would advertise exactly what you said, and eventually they contact us, they were asking questions like, “I’m I allowed to do this or not?” And we just really kinda just chat with them. It’s like, “Do you wanna get into the Radon world? And if the answer is yes, then you need to get licensed.” And we’ve had at least one of them come by and say, “Yeah, I think licensing is probably the prudent thing for me to do.”


BO: Okay, alright.


TM: I’ve got a more general question, Josh, just curious, and this is Minnesota-specific, do you know what the average number of existing homes that have Radon levels above four picocuries per liter is versus new construction homes here? 


JK: That is a good question. We’ve done some research on that. This isn’t a case control study by any means, but generally speaking, this is what we know: Of all the data that we’ve gathered in the last, say, 15, 10-15 years on Radon in Minnesota homes, 45% of Minnesota homes will have a Radon level of over four, so flip a coin, 50/50-ish. And that can vary, but kinda depending upon where in the state you’re looking, generally speaking, the southern half and the western half are higher, percentage-wise, than say the Arrowhead, but that doesn’t mean that every house you test in Duluth is gonna be low, nor does it mean every house in Mankato you test is gonna be high. So 45% existing housing stock. When we look more closely at as-built homes, and this is a study from, I think we finally published it in 2015, we looked at houses built from 2010 to 2012, after the new Minnesota building code required passive Radon features in new homes. What we saw was we tested nearly a 1,000 of those homes in 13 different counties, and we saw only 20% of newly constructed homes had a Radon problem.


TM: Mm-hmm, 20%? 


JK: 25-22, it’s not exactly apples to apples. They’re not exact same comparisons, but we’re comparing one data set to another, saying it appears that what we’re doing in code is making a difference, so now we only have to activate one-fifth of these houses as opposed to fixing almost half of them, so we’re actually, from a public health standpoint, moving ahead of curve as far as prevention, so the building code is there to help prevent Radon from entering. The regulations from my office are there to help mitigate the existing Radon problem that’s in an existing building.


TM: Well, ’cause we run across a lot of people that are buying new construction houses and they know that they’ve got the passive system and they’re not concerned about it at all.


JK: Yeah.


TM: But, there still are houses out there that have high Radon even though they’re new construction.


JK: Absolutely, there are. And, in fact, when it’s not done perfectly, I mean you did the bits and pieces are installed with the greatest attention to detail in new construction, we see that some homes are actually much worse than they would have been. You’re basically creating a Radon collection system under the house that doesn’t have a power source to suck the Radon out. So it can just gather, and if you’re not seeing the gaps and cracks, especially with the cold joint in these new homes, good luck winning the Radon game, that’s the most imperative thing, if you take nothing else away from this. And the new building contractors out there, please caulk the cold joints in your new houses to keep the basement air in the basement and keep the Radon from coming in.


RS: That’s interesting.


TM: What’s the cold… What’s the cold joint, Josh? 


BO: Cold joint, the floor wall joints where the…


TM: Oh, okay.


JK: The floor meets the concrete block or concrete walls.


TM: Okay, okay. Yep, got it.


JK: Yeah, as far as Radon entry points go, that’s probably the biggest one we see on a daily basis, construction control joints too, whether they’re cut or they’re preformed, open sump baskets, which is no longer allowed in building code, and then earth in crawlspaces, which also isn’t really allowed by building code anymore either.


RS: What’s the best way to deal with the basement bathtub drain? 


JK: If you got access to it, foam it. Spray foam it closed, you can always break it up later, you can seem like the four… Or the three-foot or four-foot long extensions for your spray foam cans, it can reach under a lot of things to foam them closed. If it’s just a knock-out, the knock-out comes loose, you can always caulk around the knock-out, but then obviously you will need to put some sort of something on it, right? Bathtub or a shower, fill it, make it airtight. However possible, but make it airtight.


RS: Okay. Cool.


BO: Josh, I’m in the middle of building a cabin right now, and our foundation sits directly on bedrock, and it’s a crawlspace, there’s not a lot of condition space down here, with the exception of all the mechanicals and some storage and whatnot, and I’m kind of having a conversation with the contractor about, “Well, what do we do, and is Radon a concern here?” “We’ll get it tested, we’ll have a look at it.” But what do you say when you’re directly on bedrock, because is that a much different situations, what you said that Canada has got more of this as a concern than we do farther south.


JK: Well, bedrock itself still has all the same components of a lot of the dirt, but what also bedrock has is gaps, cracks and fissures in it too, that can be connected to toward knows what. So just because you’re on bedrock doesn’t really mean a whole lot to me, other than you’re gonna have a really sturdy structure.




RS: Well, that is true.


BO: Yeah, I wouldn’t really handle it, I mean, I would just have your contractor follow the building code, it’s really prescriptive in what to do, get yourself a soil gas collection mat that’s gonna at least allow you to capture any Radon that might be there and get it back to outside.


RS: Getting back to the licensing thing and specific requirements, if you do have a Radon mitigation contract or pulling a tag, basically, that’s the version of a permit, they’re pulling a tag to install one of these mitigation system. What all is included with that? Does the state come out to inspect the work when it’s all done? 


JK: We won’t get out to inspect every job, but we do get out and inspect every licensed individual on an annual basis. And what we find is that contractors get into that, whatever type of system they install on Monday, they’ll install it on Tuesday and Wednesday and Thursday, and they don’t just all of a sudden say, “Oh, it’s Friday, I’m gonna do a better job, or a worse job.” It’s… They use the same materials, the same techniques, what you see on Monday again is what you’re gonna get Thursday. So we’re in the midst of inspecting everybody, we’ve been doing this now for thirteen months. When we find issues, we can issue what’s called a correction order, really right now, it’s more of a compliance assistance approach, meaning the end game of any regulation is to get the regulated party in compliance, it’s not to hammer them with fines and paperwork and all that extra stuff. It is just to make sure everybody is in compliance, and everything installed is in compliance with the minimum codes. So we go out and we make sure that they’re in compliance, and if they’re not, they’ll get an inspection report that says, “Hey, we found X, Y and Z wrong, here’s your time frame to go back and fix it them, don’t let it happen again.”


JK: And so you’ve got contractors that do really, really good work, who then may not need to be inspected as often, and then you have the problem child who may actually get visits onsite to make sure that they’re doing it right, because to make sure that everything is brought up to the minimum standard of compliance. So yeah, we’re not going to be able to inspect all four or six thousand systems that are installed in the year, but we are inspecting every company and every individual that’s licensed to do all that work. Those are kind of spot inspections, routine inspections for the professionals, any sort of requests from homeowners, on that system tag you mentioned there’s a phone number to call for the homeowner, if they see it they can call and request an inspection, that’s free. We’ll come out and do that. And then also any complaints that come in, they’re private information, but we’ll go out and inspect any complaint that comes in too. And that could be from a homeowner, a code official, a home inspector, another contractor, if they see the pipes say venting right by a window, call us up, we’ll go out and inspect the inspection and take the appropriate regulatory actions.


TM: What are some of the most common defects you see, Josh, with installed systems? 


JK: Most common defect, I can’t give you the most common, but can I give you a top three, in no particular order? 


TM: Yes, please.


JK: Okay, I would say not meeting the proper exhaust points, and there’s a whole different, whole slew of different illustrations in our standards about where it can be exhaust and where it can’t. No active alert notification system on these, not be installed, they need to be installed, so the homeowner’s aware when the system’s no longer functioning, they’re alerted to the fact that it’s not functioning. The older iterations just simply had a pressure gauge that had a U-tube gauge. Well, homeowners don’t always look at that, some homeowners, some buyers don’t even know it’s there. So if the Radon fan fails and they’re not aware of it, and they go back to sell the house in five or ten years and the Radon fan’s dead, well, how long has the Radon fan have been dead? So actually, that’s probably one of the biggest ones. Exhaust points and then also ceiling, ceiling to gaps and cracks in the floor, it’s really important, very important, not only from Radon entry standpoint, but more importantly from an energy consumption standpoint, so ceiling alarms and the exhaust points would be I think my top three right now. My other inspectors may correct me on some of that. Those are common.


RS: For the alarms, this is… I wasn’t even aware of this, I don’t know how I…


TM: Me neither.


RS: But can you just tell me how those alarms work? 


JK: Sure.


TM: Have they been required for a year now? 


JK: They’ve been required since June 1st of 2020.


TM: Okay.


JK: But even further back than then, we adopted a consensus-based national Radon standards in our rules, so we as a state didn’t have to go through the regular role of coming up with all these different rules, we can point to a consensus process from ANSI that is working through continual maintenance of these standards and since, I wanna say 2015, it’s been a requirement for chemical vapor intrusion systems that it has an active alert. It doesn’t have to be an audible alarm, but that’s the most common. But it could also be some sort of indicator light, like green light, red light, if the power is on, and it can also be like a telemetric type of system. For single-family homes, it’s probably a little much, but if it was a big multi-family building, an email or a text message or some sort of message would be sent electronically to somebody, it would say, “Hey, the fan’s not on”, and so that’s been required, actually been the standard since 2017 for those that are nationally certified professionals.


JK: So fast forward three years in 2020, it was a big surprise to a lot of our contractors, we’re training on it, we’re making people aware that, “Hey, these are the requirements that are coming.” Unfortunately, a lot of the individuals never heard it, never saw it, and then they get an inspection saying, “Hey, they didn’t put an alarm on it”, and then they’re surprised.


RS: What is the most common way of having this alarm? What do most people do for this? I mean, how would I know I’m looking at it? 


JK: Ah, well, I’ve got one in a box, I can show you the most common one if I can just go grab it.


TM: Oh, yeah! 


RS: Yeah. Yeah, I’ll take a screenshot of it.


TM: This… I had no idea that alarms were required. No idea.


RS: Yeah, this is news to me. Well…


JK: Reuben, that’s unacceptable.


TM: I don’t think I’ve ever seen one.


JK: You know everything.


RS: No, I do not. [chuckle] Quite obviously.


JK: Alright, well, here is a common system alarm, it’s not the only one in the market, they come in a few other ways, in elbow shapes and sizes, but this particular one has a connection here, a tube connection, and I’ll let you get a screenshot of this too, so you can share it on your podcast, but it connects to the Radon system almost identical as the U-tube manometer would, but this then is set to the system pressure, so when the system loses pressure, the alarm sounds. It sounds like a smoke detector kind of thing, and it allows the home owner to be alerted that, “Hey, the fan’s not working, the system’s not running properly”, and there’s also a hush function here too, so it’s not going off continuously, but these are required on all Radon systems now installed in Minnesota.


RS: Wow, so for anybody who doesn’t wanna take the time to go on the shownotes and look at the a picture, he’s basically just holding up a little box, it’s about the size of a deck of cards, and it is clearly an alarm, it says that… What does it say on there? Radon…


JK: Radon system alarm.


RS: It says Radon system alarm, plain as day. I have not seen one of those in my life.


TM: Me neither.


JK: Well, today, you were today years old when you learned, right? 


RS: Yeah. [chuckle] Exactly. Alright. Very interesting.


JK: And when you stump Reuben, you’re doing a good day’s work.




TM: I smell another blog coming along here. [chuckle]


RS: Ah, you know it Tess. Yeah. [chuckle] Well, that’s what we learned today.


BO: Can I ask a very technical question about new construction? It feels to me like with all the plastic that’s supposed to be underneath the slabs and that kind of stuff that a lot of the… There’s an impenetrable layer that wouldn’t allow the Radon to actually leak into the house, except for the tube that’s going up presumably through the middle of the house. Is that not the case? I mean…


JK: That is just not the case. What’s expected in Building Code is 6-mil poly, pretty thick stuff, generally speaking, can withhold a lot of, I should say, relatively speaking, can withhold a lot of puncture resistance, I can’t remember the term, but most of the time we pour concrete on top of that 6-mil poly, and I don’t know of any cement layers that are levitating and not walking on that, so even though we think it’s airtight, it’s not. It’s got holes in it everywhere, whether by accident or on purpose, and you used to see contractors just popping holes in it, ’cause they thought the concrete would cure better. It’s also not sealed, it’s just laying. So, it’s term in the building code is soil gas retarder. I actually make the argument in all my education classes that it doesn’t retard any soil gas, it retards the concrete from filling the gravel void below, and that’s the important part. The concrete slab, building science research will show you, the concrete slab is more airtight than the plastic underneath it. As long as… As with the caveat, as long as that slab is sealed from above.


BO: Okay, so Josh, now that we’ve had licensing in effect for… Well, it’s about two and a half years now. Is there any interesting data that the state has collected worth sharing with us, or is it all just kinda, “Yeah, this is all the stuff we already knew”? 


JK: You know, we are in the midst of cleaning the data to get in to our data sharing partners at the environmental public health tracking system, so I don’t have anything real fancy and shiny to share with you today, but I would imagine by the end of, say, October, we’ll have something, certainly by the end of the calendar year, that would be newsworthy to share in a press release. We’re usually trying to come up with some sort of new “news” for our Radon action month, which is in January. So I’d imagine we’ll have some sort of nugget in there about what we’re seeing for Radon data, say from self-reported laboratories versus our professionals, or what percentage of homes and real estate transactions have high Radon, that kind of thing. That’s the kind of information we can start to suss out here, but we haven’t really done that yet.


RS: Okay, and then how about Radon numbers for 2021? Here at Structure Tech, we have seen a dip in the number of Radon tests on average, we’re doing about 10% less this year than we did in the past, saying it used to be like somewhere around 60%, all of our home inspections would get a Radon test, now it’s like 50%. We’ve seen a drop. Has the state seen a drop too, or is that just our business? 


JK: Well, it’s too early for me to tell you from a testing perspective, ’cause I’m not gonna get any real hard 2021 data until roughly the first quarter of 2022.


RS: Oh okay.


JK: What I can tell you is, we had the most successful outreach education program this last winter. We had five times as many web hits and test kit orders from the general public, probably ’cause we’re sequestered at home in the pandemic and people wanting to take care of these things.


RS: It makes sense.


JK: Totally. Yeah, I actually thought our… The algorithm was busted because the numbers were just so much higher than they’ve ever been, which is good news after trying to dig in to see if this is all legitimate, and it appears to be. I can say that we’ve sold almost 5,000 tags tests already this year through… That was through like mid-June. So, we’re ahead of any pace that we’ve ever been on as far as mitigation system installations go. How that relates back to the 10% depreciation, I really don’t know. Is it the time of year? I don’t know, I mean, the housing market has just done been so crazy that it’s so hard to pinpoint what exactly is triggering some of these things.


RS: I suspect part of it is just that less people are getting home inspections today, we know that, because the market is so hot. And I have a feeling that people are saying, “Alright, I’m gonna get the home inspection, but I’m gonna skip any of these other things, because it’s so hot.” But that’s just me speculating, I really don’t know.


JK: Right yeah, and we don’t know either. We’re in your shoes too and when we get our data every year and we’re like “Well, we don’t know what really happened? What can we go back and look at?” We go back and look at home builds and home sales, and we’ll go back and look at our quarterly reports from our professionals to see, was there a lot more work or was there less work or was there just like a, for whatever reason, the spigot, somebody turned off the spigot, in mid-June or early-July or something. I… We’ll have to find out.


RS: Sure, and then a follow-up to that is that I’ve heard a rumor that once you get to out-State Minnesota, you kinda get outside of the metro area, the number of licensed professionals kind of falls off a cliff and you get into a lot of smaller towns and they don’t have licensed Radon testing professionals. So for real estate transactions, and again, this is just what I’ve heard, I don’t have any first-hand experience, but I hear that the standard in all these smaller communities is the seller, they will always perform their own Radon test and share that with anybody buying and everybody just kind of nods and they say, “Yeah, this is how we do it”. Have you heard anything about this? 


JK: Nothing.


RS: Okay.


JK: Nothing at all.


RS: Alright. Very good that’s alright.


JK: It’s not to say that it might not be happening but we do have professionals in but I guess they call it Greater Minnesota or…


RS: Yeah.


JK: Not out-state, but Greater Minnesota. But no, I haven’t heard anything, I haven’t gotten any complaints to my knowledge of, “Hey, we just can’t find a professional.” So…


RS: Okay, well, that’s good to hear.


JK: Well, and if there are areas that are underserved by anybody that’s listening, let us know, because we can start trying to recruit professionals. We can come up with some unique ways to at least make the training available to them or point them in the right direction to get licensed. There are so many different helping hands that we can offer that we don’t want this to be happening at any home sale. It never should be for one, but I guess the other talking point I kinda want to get off my chest too is there’s never a house that we can’t fix.




RS: That’s good.


BO: That’s a good segue, because I wanted to go into this right sizing concept that you were talking about earlier. You mean this isn’t just one-size-fits-all? 


JK: It is not, not by any means. Contrary to what some contractors might tell you, half the systems that they install may be too big, some of them might be too small, but it takes a real skilled hand and at least a little bit of building science and know how and experience to do it absolutely perfect. What we don’t wanna have are systems that are moving too much air, because some of that air that’s coming out of the Radon pipe is coming from the basement. No matter how much sealing you do, you’re gonna lose some conditioned air into that Radon system. Rule of thumb in our training courses is that we save roughly 50% of the air in a Radon system that’s coming from the house.


JK: Okay, well, if your Radon System’s only moving 30, 40, 50 total CFM, 15, 25 CFM, not a big deal overall, but if it’s moving 150 CFM, and now we’re going 80 CFM out of the basement continuously, that’s a lot of dollars and cents going up that stack, and that’s in addition to electrical cost. The more air you move through a Radon fan, the more electricity it uses. Now these fans run somewhere between, on the low end, for like a fan for a new construction is gonna be like 16 to 20 watts, so like 20 bucks a year to operate, electricity-wise. Middle of the road Radon fans that are used probably on two-thirds of Radon projects, they’re gonna be in the 50 to 60 watt range, and they’re gonna move 30 to 70 CFM and then on the larger projects or bigger fans to move up to say, 150 CFM. So, just to give you basically a dollar a watt per year to operate these things.


JK: But the more air you move, the more air is probably… Likely coming from the house, and that is a long-term operating cost that can… We got the calculations that we share with these all the time in our advanced courses. We’re not talking dozens of dollars a year, we’re talking hundreds of dollars a year times 10 years for the life of that fan, you’re talking thousands of dollars in potential energy savings just by installing exactly what’s needed, not the max of what you can deliver.


BO: How do you determine what’s needed? 


JK: Diagnostics. Pressure field extension diagnostics. So I’ll explain it real crudely. So you’ve got a rectangle, northeast southwest from the corners of the house. You put your Radon system in the north corner, and you go to the east corner and you’re gonna drill a half inch hole through the concrete slab, and you measure the pressure change when the fan is on and when the fan is off. And if you can connect those two dots with the fan running, great. Then you go on to say save the south corner or the west corner, and you map the basement. It’s a very rudimentary, crude way to explain diagnostics. But what you wanna get is a pressure change of just a few pascals in the far reaches of the basement. If you’ve got a lot more than that, you don’t need that much air flow, so you can actually either use a gate valve and cut down the air flow or some fans have an actual throttle on them, you can turn it down and just turn it down until you get the pressure number in the far reaches that you need.


JK: So if getting say 50 pascals in the far corner, you don’t need that much, it’s overkill. So let’s dial it down to just a little wiggle that you need, and you’ve just saved hundreds or thousands of dollars on the life of this fan. And it takes anywhere between 20 and 60 minutes in additional time to do this. So it’s really something that’s near and dear to my heart and something that I kinda get on a soap box about, ’cause I think it’s super important. And let’s face it, energy is not gonna get any cheaper. Also, heating your home isn’t gonna get any cheaper.


TM: Well, I just wanna go back. I’m still digesting what you said, that 50% of the air in those mitigation pipes comes from the house, comes from the basement. Not only is that an energy penalty, just the cost of heating, cooling, going up and out through your house, but just thinking about having another basically a suction point that’s causing depressurization in the basement. And if someone has a combustion appliance that’s a natural draft appliance, like a water heater or an older furnace, then that could cause a system like that to potentially backdraft flue gases into the house. Right? 


JK: Yep, absolutely. We see it, it’s not terribly common ’cause most of the resin stalls are… When you have the natural Ventil appliances you’ll have make-up air or it’s a leaky building, but absolutely, we see it happen on your inspections, I’ve seen… I’m certain you see evidence of backdrafting a lot of water.


TM: Yeah, so the Radon system can make that worse or make it bigger than that.


JK: Imagine having a house of 10 people that you’re entertaining over Thanksgiving where you’re showering, you’re cooking, you’re doing laundry, and you have a Radon system that’s maybe pulling way too much air, that house is now under super negative pressure ’cause you’re using your only exhaust fans too. Worst case scenario, yeah, absolutely, the backdraft appliances just makes it even more imperative to get on the soapbox for Carbon monoxide detectors too. Get them, have them, change the batteries, replace them as needed, it’s a must too.


RS: You mean in that negativity inside the house has nothing to do with the amount of relatives in the house? 




JK: It would increase the amount the house sucks. That’s for sure.




TM: Yes, I love it.


BO: I wanna ask you one other kind of technical topic question while we’re on this. You and I had chatted about this a while ago, Josh, but it has to do with where you need to terminate that Radon pipe and also why we need to have Radon fans installed on the outside of the house.


JK: Alright.


BO: That’s just something that bugs me a little. I’ll leave it up to you to change my mind. Let me throw in my argument real quick. You’ve got furnace fans. They’re taking deadly Carbon monoxide and they’re pushing that under positive pressure out of the house, and then we’ve got a terminal that can be within four feet of an openable window, exhausting unknown hazardous substance, Carbon monoxide, and we rely on the fact that you’re going to seal the fan, seal all the piping, to glue all the joints, and all of it is going to get out of the house. Yet, we take Radon gas, which kills people over a long period of time, and we say this is so stinking deadly that we’re not even gonna let you have the fan inside the house. You need to move the whole fan to the outside, so that the whole pipe is under negative pressure. So if there’s ever a rupture in the pipe, you’re not gonna have gases coming out. The air is going to go into the pipe instead, and if there’s something that goes wrong with the fan, the fan’s not gonna do any of this. And I feel like we are just way over the top with this. Josh, changed my mind.




JK: Well, Bill there’s one in every bunch, right? You mentioned it before.




BO: Yeah. [chuckle]


JK: Alright, so we’ve got a lot of experience in this, in the United States. And what we found is a little bit of history background where Radon came to fruition really because of a happy or not so happy accident, and that is a family in Pennsylvania. The gentlemen’s name was Stanley, Stanley Watras. Stanley Watras was an engineer who was working on building the Limerick power plant over in Pennsylvania. He would show up to work and go through the radiation detectors and they would go off. There was no fuel on site.


JK: So one day he got so sick of having to go through the decontamination process that he walked through it and then walked out and he set off both alarms. But, normally he would walk in, do his work, and then leave for the day and when he left, the detector did not go off. What they found was that he had Radon decay products all over his clothes from his house. His house was thousands of picocuries. He’s in a Reading Prong area in Eastern Pennsylvania. It’s a known geologic formation, but super skyrocket Radon.


JK: So at that instance, the EPA said, “Okay, circle the wagons, let’s go in to see how many of these houses have problems. How much Radon is in the soil? How much is outside? How much are in these houses? And they found a lot more homes were higher than they ever imagined. They kind of thought this may have been a one-off. Clearly it’s not. And so the amount of Radon in Stanley’s house was sky-high. It’s comparative to what we see in soil samples throughout the country. So only a small amount of the Radon that’s in the soil gets into the house, a fraction of it.


JK: So if we we’re always breathing on the soil, we would always be breathing 100 or 1,000 or 5,000 picocuries. It’s that concentrated. So when we… Two things, when we have a fan in the basement and then that fan shell leaks, or as you mentioned before, a pipe fitting above the fan leaks, now we’ve got Radon, in super higher concentrations going into wall cavities or into the basement, and guess what we’re not testing for? Radon. So Radon could be super high even though you have a Radon system in the house but it’s not properly installed, it can make the Radon so much higher. There are plenty of examples from the EPA research that showed when… There’s actually one story that comes to mind but it had a media blitz where they said, “Alright, we fixed this house. Come on in TV cameras.” And they go and they vented this one at grade with a fan on the basement and they went and they pushed the button on the Radon monitor, the Radon was high because the Radon was going outside and then coming right back in.


JK: So it’s the threat of re-entrainment and the threat of leaking Radon through either someone put a hole in the pipe above the fan or a joint coming loose. Maybe they forgot to glue it. Maybe it came loose. But from a public health perspective, if we have just one house that’s too high, that’s too many. So we take the belt-and-suspenders approach. We put the fan outside the conditioned space of the house to limit the amount of what Radon that likely trimmed that fan and come back in and then get the exhaust point up over the roof and propel that straight up in a way so that spung doesn’t have a chance to reenter. So that and the couple with two, there is more stuff in the sub than we’re aware of. There are stuff in the soil that’s more acute.


JK: Talking like TCEs or methane, gasoline that might be in the soils as far as these chemical vapor sites. The health effects from that can be very quick, especially the feel effects, instant. So we need to be as protective as we can, and that’s why you got fans outside and exhaust points where they are.


BO: Sounds good. Thank you, Josh. I appreciate it.


JK: You’re welcome. Did I change your mind? 




BO: A little, it gives me more background. It’s better safe than sorry. It’s all about your tolerance to risk. I probably have a higher tolerance than a lot of other people, and when it comes to the state, I’m sure it’s much lower than others, and it helps me understand it. So, thank you, I appreciate that.


TM: You know, one thing that strikes me is that there’s no standards for gas ovens or ranges in people’s houses. And that just blows my mind because those appliances burn gas and they have no vent to the exterior. They just vent right into your face and people are using them every single day.


JK: Or you have the flipside of that, where you’ve got these wannabe Home Executive Chefs that have a giant, tens of thousands of BTU burner stove top, right? And then you’ve got the equivalent commercial hood. So, when they just wanna boil a little pot of water and they turn the vent on, no one ever turns it on low, right? Let’s just crank it all up.


TM: Yeah.


BO: Yeah.


JK: Where is that 600 CFM make-up air coming from? Certainly, there’s controls now in more modern houses but not you can say that. You think that can induce a Radon problem? 


TM: Yeah.


BO: Yeah, no doubt.


TM: Radon problem and back drafting problems.


BO: My question, how often should a homeowner be re-testing if they have an active system in their house? 


JK: Homeowners should retest every two years, and they can do that by themselves. As long as they’re comfortable following instructions, you can get a test kit from our partner website, for $11 or $12. You go to your local county health department that often has them for reduced cost or even free, or the hardware store. Big-box store Mom-and-pop, neighborhood stores may have one too, just be sure you follow the instructions and you should get a valid result.


BO: Great, thank you. Now, to put you on the spot. You referenced some great building science minds that you’ve worked with. Do you mind sharing who these people are because the more good building science minds we know, the better off we all are.


0JK: Well, I haven’t actually worked side-by-side with him, but I mean, who’s not entertained by just reading his articles, right? 


RS: That’s right.


JK: The Radon pioneers were really the ones that I was talking about. Terry Brentwood, would be one, more close to home. In fact there’s a picture of them behind with Kevin O’Connor. That’s Jack Bartholomew, a dear friend of mine and former Late Radon Mitigation trainer. He taught me everything I know and really turned the energy efficiency in my mind. If You don’t see there too, it says obituary from seven years ago already, this July 6. But he trained the vast majority of our Radon contractors worked in the upper Mid West, Minnesota, Iowa. If they’ve been in the game for longer than, say seven years, they know who Jack is.


BO: Well, I’m sorry that he’s gone, but thank you for sharing. That’s good stuff. Well, I think we should put a bow on this one. We could go on for three hours.


TM: We could keep going. I have more questions, but we’ll have to have you back, Josh.


JK: You can book part two whenever you guys want.


BO: There’s a trend in that statement that happens on a rather regular basis. When we start talking with somebody, we’re like, “We have to have you back again,” because there’s just never enough time.


JK: Hey, I would be more than happy to do that, and we’ve got plenty of case studies too to go through. Even the simple ones just to show you guys the importance of right sizing and the energy savings that can come with it. More than happy to do that anytime.


TM: Cool.


BO: That’s outstanding. Thank you, Josh. We really, really appreciate it. And for any of you who were not familiar with who that is, that’s Josh Kerber with the Minnesota Department of Health. He is the Technical Radon Lead, and he knows everything there is to know about Radon. Thanks for spending an hour with us and taking on Reuben’s question. He’s the doubting Thomas over there, he’s straight on. [laughter]


JK: No problem. I appreciate it, guys. This was a lot of fun. Let’s do it again.


BO: Well you’ve been listening to Structure Talk, a structured tech presentation. My name is Bill Oelrich alongside Tessa Murray and the doubting Thomas, Reuben Saltzman. You are listening to Structure Talk, a structured tech presentation. Have a great weekend. We’ll catch you next time. Bye.