Also, please enjoy these old photos from 1997, featuring Reuben and Rick wearing lab coats, testing for radon. Good. Times.
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.
Speaker 1: It can get stuck with dust and then we inhale the dust, and over a long time it can cause damage in ourselves, in the lungs and then eventually cause lung cancer.
Speaker 2: If you live in a house with a basement, the chances are you’ve had a radon test. But what do the numbers mean, and just how safe or dangerous is it if they are below or above the recommended exposure level? Radon is a naturally occurring radioactive gas. It’s one of those substances that it’s pretty much impossible to avoid as it’s constantly being produced by other materials in the earth’s crust. And because it’s radioactive, it has the potential to cause lung cancer if you inhale it at high levels for long enough. For most of us, this isn’t worth worrying about too much as we can’t avoid breathing small amounts of the gas. But if you’re living in an area where there are high levels of radon it can be an issue.
Bill Oelrich: Welcome everybody to Structure Talk, brought to you by Structure Tech. I’m your host Bill Oelrich alongside Reuben Saltzman and Tessa Murry. Today we’re gonna talk about radon. Up in Minnesota, radon testing is now something that it requires a license, you have to be licensed to test and to mitigate in the state of Minnesota.
Reuben Saltzman: Almost, almost mitigate. It was actually a law, they said you need to be licensed to mitigate starting January 1st of this year. But then it got kicked back. The mitigators really fought it, it’s in limbo at the moment.
BO: Okay, there’s currently a court injunction on the mitigation portion of this.
RS: That’s right.
BO: But we’re gonna try to clarify what radon testing is all about, how you do it, all these kind of good things. It’s something that happens in real estate on a regular basis. And so I’m gonna throw the ball to Reuben, and he’s gonna tee it up, he’s gonna tell us all about radon testing. It’s a part of our company, it’s something we do, we have three full-time people who drive around and do this. So Reuben, what’s the deal with radon?
RS: Well, radon has been a thing for quite some time now. I remember when I first started with Structure Tech, we did radon testing then, this was back in ’97. We had this thing where we tested right in the office. We would place canisters in a home, and we’d bring them back and we had a lab, it was crazy.
BO: Did you walk uphill both ways to the house?
RS: We took pictures of me wearing a lab coat, it’s awesome.
Tessa Murry: Oh my gosh.
RS: I will dig up that photo and I’ll put it on this podcast. So we’ve been testing for radon for a long time. The whole issue with radon, it’s a naturally occurring element, it shows up in the ground, it starts as uranium-238 or something and it decays and it changes to this and that, and over part of its decay period it turns into radon. I don’t know how long it is, I know the half-life of radon is 12 hours. It causes lung cancer, that’s the bottom line. And there’s controversy over that where some people say, well, the science isn’t good on that and it doesn’t cause lung cancer, or the testing’s flawed. And I don’t get into all that. I’m not a scientist. Here’s the facts, the American Lung Association says it causes cancer, the EPA says it causes cancer, the surgeon general says it does, all of the authorities…
TM: And isn’t it the second leading cause of lung cancer deaths next to smoking?
RS: That’s the statistic you always hear, yes. So there’s all this information out there saying it causes lung cancer. Okay, let’s just say it doesn’t, let’s say it’s all just a farce, and all the science is completely junk, is it something that we can test for? Yes. Is it something that is fairly consistent? Like if we test and a home has really high levels, if we test again in two years, is it gonna be really high? Probably so. And is it a liability if you’re buying a home? And it has a high level of radon, is this a liability for you? Yes, unquestionably.
BO: Well, the buck always stops as somebody. So you can have the conversation before you own versus after you own.
RS: Yeah, yeah, exactly. If you test for radon when you’re buying a home as part of the purchase process, you have the luxury of asking the seller to fix it if you have a high level. Now, sellers don’t have to do anything, there’s no laws about what needs to be done with high levels of radon. And maybe that takes some digging into.
BO: What’s the most common question Tessa you take during a class?
TM: Well, a lot of agents are wondering, “Is it even necessary to test for radon in new construction, newer houses?”
BO: So why would you pull out new houses from this testing equation?
TM: Well, the way that they’re built today, people think that there’s less chance of having that radioactive particle actually coming up through the slab into the house because of how they build it, but studies have shown that there still can be high levels of radon in new construction. Reuben, what have we found in our testing with doing these radon tests in existing homes and new construction?
25 RS: Well, and just to clarify, when we say new construction I’d say anything in Minnesota built approximately June of 2009 through today, that’s what we’ll define as new construction because that’s where we put a law in place saying all new homes need to be built with a passive mitigation system. So there’s a very clear dividing line there between newer and older houses.
BO: So sellers aren’t required to really do anything. This is just great information for you guys to know about, you can negotiate on the front side. You said there’s a passive mitigation system, let’s leave that for later.
RS: Sounds good.
RS: So Tess, to get back to your question about the difference between new and old, basically when we’re testing existing housing stock, about 40% of them are gonna have high levels of radon, a level at which the EPA says you should mitigate. And for newer homes that already have passive mitigation system, we find high levels at about 20% of those homes.
TM: Yeah, a lot less but they still can have high radon.
RS: Yeah, it’s still definitely important to test.
TM: And the only way you know is by testing.
BO: So when we come back we’re gonna talk about where radon’s found, is it specific to a neighborhood or is it wider? Is there a geological feature to our area that makes radon more or less prevalent or what do you know about this?
RS: It’s all about soil content. And the one big difference we found is that when you seem to be closer to lakes and heavy clay in the soil, we find heavier concentrations of radon, when you’re in sandier soils, maybe Anoka, Northern areas, there seems to be less but really you don’t know. I wish that I could just say these neighborhoods are really bad, and these ones aren’t, but really you have to test. It’s tough to make generalizations.
TM: And Minnesota has some of the highest radon levels in the country.
RS: Yeah, we have very high levels here.
TM: So it depends on what part of the country you’re in, and how much uranium deposits are in the soil.
BO: So one of the guys on our team, just put up on our internal Facebook page, a map called the, what was it, the Anoka sand zone or something like this? We’ll link it to this presentation, but it’s this great map which shows the deposit of all this very sandy soil. So maybe if you’re in one of those areas, maybe you got a better chance. My question is, if you test and you’re low today is that a guarantee that if you test in 10 years, you’re still low?
RS: Well, a lot of variables, if you don’t change anything in your home, everything stays exactly the same, you’re probably still gonna be low, but there’s stuff that can change underneath your home. Soils can shift, things can open up, your slab can shift and you can have new cracks developed that you don’t even know about that can start emitting Radon. Go on.
TM: The other thing is, too, with the Radon testing, there’s different tests you can do, you can do short-term test, long-term test. The testing that we do at our company is considered a short-term test and it’s a 48-hour long test with a computer basically, that collects data. The radon levels that it collects, they fluctuate based on weather, wind, occupant behavior, a lot of different things. The most accurate type of test you can do is a longer term test, something that’s like a six-month long test, or a year long test, because radon levels fluctuate annually too. And so to get out more data points and a longer average, it’s gonna be more accurate.
RS: Yeah, and a really important part about doing a short-term test. The EPA threshold for a real estate transaction, they say, “If it’s at four or above, somebody ought to mitigate,” that’s the trigger. So everybody kinda hangs their hat on this four number. Alright, if we do a short-term test and it comes up at 3.9. “Oh great, you’re safe.” There’s a lot of margin of error. The devices that we use have to be within 25% at that level. It’s a big swing. So it might actually be closer to five when it comes up at 3.9, we don’t know. So what we’re getting at here is that even though the EPA says four is the threshold they’re saying that because their advice, if you’re just testing your own home, if you’re a home owner, and you’re gonna do a long-term test, they say if it comes up above two, you should fix it, you should take steps to lower your radon levels. So that’s really the action level.
RS: Now if you’re doing a short-term test and it comes up at four, like twice the level where they say, you should fix it, if you’re a home owner, then you’re surely gonna have elevated levels throughout the year. You might come up at 2.2 if you test again, a few months from now, but still they say, “That’s so high that you ought to do something about it.” So don’t get hung up on this four being a magic number. It’s just saying, “Look for a 48-hour test if it comes up at four, you ought to do something about it. It’s not a good number if it comes up at 3.9, that means you should follow up with a long-term test and see if it really is 3.9 all the time and if it is, fix it.”
BO: Yeah. I had an interesting conversation with real estate agent recently who would talk to that 4.0 number and he said, “I just wish everybody would keep it in general terms, this is really, more than just facts that we’re beginning to talk about, right? It’s a negotiation. It’s at 4, 3.9, 4, tomato, tomato,” He says, “Don’t make any broad statements like, Oh you’re at four, the seller should pay for a system or you’re at two, seller shouldn’t have to pay for anything.” He was like, “Leave that up to us in the real estate community to have those conversations with our clients about what we wanna do.” So I like what you’re saying about the four. Don’t get hung up on any particular number, just provide the facts and move forward. Reuben, I wanna ask you one question, what’s the benefit of a short-term test versus a longer term test? Is there one better than the other, or?
RS: Just the time. That’s it.
BO: Okay. Is short better than long?
RS: No, long-term test, like Tessa said long-term is much more accurate, but if you’re buying a home, you’re not gonna say, “Hey I wanna do a three-month test and then see about buying your house.”
BO: So Reuben, you just mentioned that a long-term test is probably the best test if you had the time, but around the real estate transaction people just simply don’t have that time. Short-term tests. What’s the best benefit you can give on a short-term test?
RS: Well, the nice thing is you get an hour-by-hour breakdown on it, provided you’re using a company who uses a continuous Radon monitor, there’s these cheap charcoal canisters that we used to use in the 90s, those just give you a number, here’s your radon level, that’s it. But with these electronic monitors we use, it tells you hour by hour what your radon concentration was. And every once in a while we’ll do a Radon test and we’ll kind of be suspicious of the sellers and we will share our concerns with our clients. If there’s something that looks like the test has been messed with, we are required under our license that Minnesota says we need to report this now and state our concerns.
RS: A good example of that would be at the very beginning of the test where we have the house all closed up, all the windows are shut to simulate wintertime conditions. We might have a really higher radon level where it’s hovering around six, eight or something and then all of a sudden, it drops off and it’s really low, it goes down to two, three for many hours and then it goes back up again. Well, it’s pretty obvious what happened, the home owners opened the windows after we left, they left them open the whole time we’re gone and then they closed the windows again before we showed up to pick up our monitor, plain as day what happened. And I’ve caught people red handed doing this. I remember swinging by a home, it was a flip house, it was in the dead of winter and it wasn’t that far from my home and I swung by just to take a peak, the basement window was wide open, dead of winter, the room where I had placed the monitor. At another one, near my home in Maple Grove, we ended up coming a day early to check on it and the monitor had been moved to the garage.
TM: That’s terrible. I’ve had the same thing happen where I go to pick up a radon monitor, the windows are open, and one was a flipped house too, where someone had been back, it was vacant, someone had been back since the monitor had been set up and all of the basement windows had been opened. We reset it, came back a second time and that time it had been unplugged and they have a back-up battery, but the battery died. So it does happen, but sellers, maybe if it’s a rental property and they’ve got renters in there, that’s an issue sometimes, too.
BO: Well, sometimes they just don’t know any better.
TM: They don’t know any better even though we leave behind documentation, send out emails, explaining the windows need to stay closed, they don’t always stay closed, especially in the summer time here in Minnesota. If a house doesn’t have central AC, and it gets really hot, trying to ask the sellers to keep everything shut is almost impossible.
BO: So Tessa, how do you get rid of radon when you’ve got high levels in your house?
TM: It’s pretty simple. Luckily, it’s a radon mitigation system that you install and well, not you. But here in Minnesota, pretty soon you’ll need to hire a licensed contractor.
RS: The royal you.
BO: It’s not a DIY project.
TM: Not really, no, but it consists of basically installing a pipe that goes through the slab, the basement floor, and then that pipe, if this is an existing house, that pipe will usually go out through the rim joist and that pipe goes up along the side of the house and terminates above the roof line, and there’s a fan installed on that pipe that is constantly sucking air out from underneath the basement slabs, de-pressuring it. And so that’s an active mitigation system. Having that fan installed.
BO: You’d call that retrofit?
TM: Yeah, in an existing home where they have high radon levels, they wanna reduce the radon levels, you install one of these active mitigation systems.
BO: So that’s why when I drive around the neighborhoods, I see a lot of houses that look like Mac trucks with this pipe running up the sides.
TM: Yeah, and a big fan on the outside. So that would be an active mitigation system, but like Reuben said, 2009 when it was code to install passive systems, basically builders install that pipe that connects to the sub-slab, usually it goes through the interior walls through the attic and up through the roof. And passive system is passive because there’s no fan installed on it. Now it’s pretty easy to make it active, all you need to do is add a fan and usually that’s installed in the attic. But you’re all set to go, and it’s pretty easy to just throw in a fan to make it active.
RS: And one of the requirements for the passive system, is that the outlet, the electrical outlet already needs to be installed in the attic right next to that pipe. So I mean, it couldn’t be simpler. You buy a fan for $150 bucks, you have a contractor, attach it the pipe, you put a little tube in the basement that shows you that it’s sucking air and that’s about it, that’s all it takes to convert a passive system to an active system.
BO: So that one pipe that goes from your basement floor through your attic is enough to drop on average 20%? Is that the difference between the 40% you cited earlier and the 20%?
RS: Wel, that’s the visible part of a passive system. The other part that you don’t see is underneath the slab, and this is where more cost is involved, is they need to put rocks underneath your slab. And I think it’s… I don’t remember off the top of my head, I think it’s like four to six inches of rocks, somewhere between three quarters and one and a quarter inch in diameter. And then they need to have a Polyethylene sheet right underneath the basement slab. So you’re creating a big air space underneath that basement slab that that pipe is connected to so it can move air all throughout the basement slab, so you have a really nice relief valve that gets installed before the house is ever built. So that’s where the big cost comes in. It’s not just the pipe itself.
BO: Okay, so you just mentioned something, moving air.
BO: Obviously I’ve heard throughout my life, the solution to pollution is dilution. And so if you’re moving air, you’re diluting things. So, what else in a house can help mitigate radon? Are there possible that houses have elevated levels of radon but there’s enough air movement that it’s just…
RS: I know what you’re getting at here. I think I know what you’re thinking, you’re talking about changing out the air in the home, right?
BO: Well, or it could be anything, is my furnace fan enough to dilute the radon levels or no?
RS: The furnace fan is only going to circulate air in a home. It’s not really gonna change radon levels, but a lot of homes in Minnesota have these devices installed in the basement called a air exchanger, or more technically an ERV or an HRV. And those devices bring fresh air into the home and exhaust stale air, and if you have one of those, and you’ve got it set to high and run it continuously, I don’t remember where I heard the statistic but the number is you’ve got the potential to cut your radon levels in half. So, if normally your radon level is gonna be at 4.2, you run your HRV all the time, and you might drop it down to 2.1. So yes, an HRV is going to affect radon levels in the home, it’ll lower it, provided it’s running.
BO: Do you test with HRVs running?
RS: Yes, we always do. And I’m very insistent upon that. This has been a debate that has gone on for a long time here in Minnesota. There’s people on both sides of it. But I’ll tell you what, I recently taught at a radon seminar that was done here in Minnesota for all the licensed radon technicians and I stood up in front of all of them and I said, “You need to have that HRV running.” I was very insistent upon this, and then I had somebody from the state come up right after me and say, “Yeah, I agree with Reuben, it should be running. We’re probably going to change our state guidelines to make it really clear, 100%. If you got an air exchanger, have it running.” You’re simulating wintertime conditions. The house was built to have an air exchanger installed, so this is normal. If you have it off when you’re running a radon test, and you have the house all closed up, I would argue that that is not normal conditions and you’re gonna have an artificially high radon test if you shut your HRV off.
BO: Okay. So, then the number you’re providing is a worse case scenario under normal operating conditions of the house.
TM: Designed normal operating.
RS: Designed, yeah. Worse case is you don’t follow design, and you shut off your HRV but that shouldn’t happen.
TM: Bill, when you’re talking about the airflow. I thought you were actually gonna mention another benefit of having an active mitigation system installed.
BO: Which is?
TM: A new construction with the passive systems, if you add a radon fan, and make it an active system, it can actually help dry out the sub-slab and it can reduce the amount of moisture that comes through and reduce the humidity levels in your basement. Make your house dryer too, which is another benefit.
RS: Yeah, it was a guy by the name of Don Sivany, he’s with the Minnesota Department of Energy, I think. He taught classes at North Hennepin, a real nice guy. I remember when he was one of the big proponents of making this a thing for Minnesota, and when he first started trying to get this push through, they were calling them sub-slab de-pressurization systems. They weren’t even calling it a radon mitigation system, because he was afraid people would reject it if they called it a radon system. But then people were very receptive to a radon system, so they said, “Well, then we’ll just call it a radon system.” But yeah, there’s a lot of benefits…
TM: It’s also easier to say besides sub slab de-pressurization system.
RS: Amen to that, yes.
BO: Thanks Ruben and Tessa, that’s awesome information. There’s one thing I just need to know about, talk to me about cost, talk to me about how the test is run, talk to me about how much it costs to mitigate if you do find high levels.
RS: Sure. Well, for short-term radon testing, if your home inspector is gonna do that, and most home inspectors in Minnesota seem to offer that now, it’s right around $200. What do we charge? I don’t even know what we charge.
TM: I think it’s $225.
RS: $225, okay.
TM: I should look on our website.
RS: Yeah, I should check too. I don’t quote prices anymore, but we had to jack our fees way up after licensing came ’cause all of a sudden, none of our home inspectors could do it, we had to buy more vehicles, and hire more people, and it was only licensed radon technicians who could do it and oh my gosh, the amount of reporting the state wants and duplicate tests. It’s just crazy. But that’s if you’re buying a home, and you need a licensed person to test. Now, if you already own a home and you just wanna test your own house, you don’t need to hire us, you can just buy your own do-it-yourself test kit, the canisters that we talk about, those are perfectly accurate, as long as you follow all the rules on there, you send it in the lab and they tell you what it is. And I’ll put a link on this podcast, you can test your own house for 10 bucks. So, I mean, I guess what I’m getting at is don’t waste your money hiring us to do that. If you’re a home owner. If you’re buying a home, by all means, have us do it, we will give you fast, accurate results, we’re very good at it. Our company probably does more radon testing than anybody in the state of Minnesota. We do a ton of it here and we are very good at it, but if you own your own home, yeah, go ahead and buy a kit.
BO: Okay. So then if you need to put a system in, what are we looking at?
TM: Well, probably about 1,500 bucks on average.
BO: Is that a retrofit system or is that just the fan on that passive…
TM: Yeah, that’s a great question. That would be like a retrofit situation. But if you’re just adding a fan to an already existing passive system, you’re gonna have to cost of the fan which is a couple hundred bucks, and then the labor. And Reuben, do you have any idea how much that’s gonna cost? I don’t.
RS: All said and done, I’d figure about 500 bucks, for the fan and the labor.
TM: Yeah. And if you’re looking at buying new construction house and you have that passive system already, would you rather spend 500 bucks and know that you have low radon levels by making it active, and reducing the amount of moisture in the house or spend $225 and just test it?
RS: I’m sorry, I’m talking us out of work. But if I were buying a new home, built 2009 past, I wouldn’t hire myself to test for radon, I would just put in a fan, period.
BO: That was great information test, Ruben. Thanks everybody for listening, we hope to catch you next time.
Author: Reuben Saltzman, Structure Tech Home Inspections
October 21, 2019, 12:56 pm
Hi Reuben. Thanks for the info on radon. We are going to be building a single story slab in grade with 4’ frost footings. Do we need to mitigate with this kind of foundations? I appreciate your response.
October 21, 2019, 1:00 pm
Assuming you’re located in Minnesota, yes. You’ll still need to have a passive system installed.
October 24, 2019, 11:35 am
Hi Reuben, great podcast! Curious about converting a passive system to an active system on a new construction: Is the active system less effective at drawing out air from the subslab if the fan is installed in the basement vs. the attic?
October 24, 2019, 1:11 pm
Thank you! The fan is supposed to be installed outside of the conditioned envelope of the home, so this should be a moot point. You have to put the fan in the attic. But to answer your question, I don’t know for certain. My guess is that it wouldn’t make any difference and that even if there was a difference, it would be negligible.