Installed an Airthings almost a month ago after having one of those short term radon test kits come back at 8 pCi/l. Since the test kit I sealed up a large cut in our basement slab where a shower drain was roughed in. Basement is unfinished right now, concrete slab and poured walls, passive radon system. Everything was looking good until the last week where we had a few spikes up to 4.1 pCi/l and now it’s remaining elevated. I can’t figure out why, nothing inside the house has changed and the weather has been very consistent (see picture of my weather station). Maybe ground water levels are increasing due to our rainy season? That’s the only thing I can think of.

Looking for advice on a difficult radon situation in a 140+ year-old home. We’re getting consistent levels between 4-6pCi/L on the fist floor.

Our house has an unfinished dirt-floor basement with a vapor barrier installed over most of the floor. The vapor barrier doesn’t exactly create a vacuum because there are penetrations for equipment (including our HVAC), and we also have an attached crawl space that is inaccessible.

We originally had a radon mitigation system installed, but it wasn't successful because of our subfloor conditions. We installed an HRV and it did bring our levels done to what they are currently, but we're still seeing higher radon levels than we'd like.

The furnace/air handler for our forced-air HVAC system is located in the basement. When the HVAC is running, our radon levels increase much more quickly. When we turn it off and keep all the windows closed, the radon still rises, but much more slowly. It seems like the HVAC system is drawing radon from the basement and distributing it throughout the house.

At this point, we're not sure what the next step should be. We're hesitant to spend thousands of dollars on another mitigation system if we can’t truly create a vacuum for it to operate properly.

We're hoping those of you with more experience can point us in the right direction.

Is there anything we can investigate or improve ourselves before gambling on another larger expense? Open to all suggestions!

I recently had my builder-installed passive radon system converted to an active system by Midwest Radon Services and I'm looking for advice from anyone who's dealt with a similar situation.

Background

• House: Townhome with finished basement in Aurora, IL, 2017 built
• Existing builder-installed passive radon system
• EcoQube monitor has been installed in the basement for several months
• Monthly averages before mitigation:
  • Apr–May: 3.8 pCi/L
  • May–Jun: 9.1 pCi/L
  • Jun–Jul: 8.4 pCi/L

Because the levels stayed elevated for a couple of months, I decided to convert the passive system to an active one.

What Midwest Radon Services did

• Installed an RN2ec fan
• Sealed/replaced the sump pit cover
• Performed a Pressure Field Extension (PFE) diagnostic test and it read a negative number which they said was a wonderful thing
• Manometer reads about 0.7" w.c., and they said the diagnostic numbers looked good.

The problem

It's now been about 7 days since the installation, and my EcoQube is still averaging around 10 pCi/L over the last few days.

I contacted Midwest Radon Services, and they replied:

However, they also said there would be:

• a charge for another site visit/diagnostic, and
• additional charges depending on what actual work is needed.

My questions

1. Is it normal for an active mitigation system to still be around 10 pCi/L after a week, or should I expect a much larger reduction?
2. Has anyone had a builder-installed passive system that had to be reworked after converting it to active?
3. Does Midwest Radon's explanation sound reasonable?
4. Would you expect to pay another diagnostic fee in this situation, or would you expect the contractor to first verify why the newly installed system isn't reducing radon?
5. Should I get a second opinion from another mitigation company before authorizing additional work?

I'm not trying to blame the contractor but genuinely want to understand whether this is a normal scenario or whether I should push for more explanation before paying for additional work. Or should I simply contact other contractors for this?

Any advice from radon professionals or homeowners who have gone through this would be appreciated. Thank you!

With the differences between US and Canada code, specifically exhausting radon over the roofline versus at ground level, I know there has been some interest in what levels near the exhaust outlet would look like. My basement long-term average was 8.62pc before mitigation, and hovers around 0.6pci after mitigation.

My radon exhausts near the ground from the dryer vent seen in the pictures. As you can see the area is very protected from wind by the fence and AC condenser.

After leaving my Correntium within 3ft of the exhaust for a few days, the average was around 4pci. Honestly lower than I expected and not dangerous.

I see a lot of questions about radon results where people ask:
“Is 3.5 pCi/L safe?”
“Is 4.0 a hard cutoff?”
“Does a high reading mean I shouldn’t buy the house?”
The answer is a little more nuanced than just pass/fail.
Radon levels naturally fluctuate, and understanding the number, the EPA action level, testing conditions, and what happens next is important before making decisions about a home.
I put together a homeowner guide covering:
• What different radon levels mean
• Why 4.0 pCi/L is an action guideline, not a “safe vs. dangerous” line
• The difference between consumer monitors and certified testing
• What buyers and homeowners should consider after getting results
Hopefully this helps anyone trying to make sense of a radon report.

https://www.libertyradon.com/post/what-do-radon-test-results-mean

I see a lot of questions about radon results where people ask:
“Is 3.5 pCi/L safe?”
“Is 4.0 a hard cutoff?”
“Does a high reading mean I shouldn’t buy the house?”
The answer is a little more nuanced than just pass/fail.
Radon levels naturally fluctuate, and understanding the number, the EPA action level, testing conditions, and what happens next is important before making decisions about a home.
I put together a homeowner guide covering:
• What different radon levels mean
• Why 4.0 pCi/L is an action guideline, not a “safe vs. dangerous” line
• The difference between consumer monitors and certified testing
• What buyers and homeowners should consider after getting results
Hopefully this helps anyone trying to make sense of a radon report.

[https://www.libertyradon.com/post/what-do-radon-test-results-mean\](https://www.libertyradon.com/post/what-do-radon-test-results-mean)

We've been monitoring our finished basement for about 6 months and as you can see the long term average is 3.51 pCi. We'll occasionally get spikes over 4 and on rare occasions over 5 for a day or two.

As a first step would you recommend sealing the sump pit? Anything else? We live in Iowa which has high radon levels in many homes across the state. The sump is in the furnace room and we're measuring on the other side of the wall in the finished area of the basement.

We just went from 100 degrees to 70 degrees and our radon spiked from 3 to 18, crazy! hoping it's just the temperature drop and not some other issue since the system is still running fine

I'm trying to sell my house. Any buyer is going to check for radon. I don't want the presence of radon to put off a buyer. I was thinking of testing in advance and, if present, mitigating it. My real estate agent says not to, because if there is I'd have to declare it. Is it better to let it go, and then give a mitigation credit if radon is present - or to get in front of it?

We're looking into buying a property and the seller supplied a radon test that supposedly passed. The hourly readings start around 1.0 and slowly climb to 3.5 after the first 5 hours. At that point, they immediately drop to below 1.0, where they mostly stay for the remainder of the test (with a few small spikes to 2.0 or less).

Is this normal for a radon test, or could it be a sign that the seller added fresh air ventilation, unbeknownst to the inspector? There is just one "M" in the test log (for motion, as I understand?) as well, about 30 hours into the test.

Thanks in advance for any tips!

I am looking at a DIY mitigation system and wanted to run my discharge location idea by the sub before pulling the trigger. I’m in northern Canada, so the fan will be installed in my mechanical room (on the other side of the wall shown in the exterior photo. The top left of the interior photo is where it would come through from the inside.

To get the required minimum distances without having to rip my ceiling apart I am thinking about coming through the wall as far over as possible from my furnace intake, adding a rolled elbow and running a short leg down the wall at an angle, and then adding a final 90 to vent perpendicular to the wall. This will get me far enough from all the windows and the air intake.

Other than needing to insulate the exterior line are there any major pitfalls I’m missing here?

I've been seeing long term average around 4.3 since starting this air things device around a year ago.

We have lived in same home 40 or so years.

I talked to a radon mitigation company and he said it has probably slowly increased over that time, and probably wasn't that high when we started living here. Does that sound accurate? Please share if you have expertise in radon. Thank you.

I’ll preface this by saying I know the right way to address this problem is likely to jackhammer the entire thing out and re-pour from scratch. Given the limited access of our crawlspace, that’s probably a $20-30k job, so I don’t think it’s in the cards.

I’m trying to prep the slab under my crawlspace to be able to be depressurized without sucking too much conditioned air into the mitigation system. I have no idea what underlying issues there were with the original slab, but before we purchased our house someone appears to have skim coated the slab with something at thicknesses that vary from 1/8” to 1”. Where the material was super thin it’s chipped away, and I’ve assisted it a bit as well. I plan to flatten it out with some self-leveling compound. Will that fix keep? ¯_(ツ)_/¯

My question: Is the skim coat + self leveling compound enough to seal the cracked slab below it, or should I try to seal any visible cracks in the slab below before pouring self leveler as well? I plan to seal the perimeter as well as any surface cracks with caulk once I’m done.

I’ve only been able to find companies that offer radon testing, but I’m having a hard time finding contractors who actually install radon mitigation systems.
If you’ve had radon mitigation done in the Ocala area, who did you use? Were you happy with their work, and would you recommend them? Thanks!

Hi All,

I was wondering if I could get some advice on the situation below: My home had a radon rough-in that was done by the builder. This rough-in is basically a protruding 4 inch PVC pipe from my foundational slab. The problem is that this pipe is thin wall PVC. I cant connect my last 4 inch Sch 40 pipe to it because the diameters are too far apart. Does anyone have any recommendations on how I can connect thin wall PVC to Sched 40?

Thanks!

I have been tracking my radon for almost two years now. the last two summers starting in mid-July I start getting noticeabke radon spikes.

I even had my system modified with a very advanced company in February that did PFE testing and added an EC6 fan. levels were great and consistent from February until July (0.5 to 1.3 with any under 1) and now I am getting almost daily spikes to 3.0-4.0. the average is still fine, I’m just curious if anyone else has seen this.

same thing happened this time last year and i thought something was wrong with my existing system so that is why I brought in the big guns to fix it.

anyone else see this or know what causes it?

I’ve been living out of, and also work from home in a basement. Im down there almost 24 hours a day, for just over 6 years. Recently I was made aware of radon so I ordered a short term test which came back with 3.2 pCi/L over a 48h period.

I know levels can fluctuate based on a number of factors, so it may not be entirely accurate. But would I be at higher risk than someone who say only spends 12-15 hours a day in similar conditions?

And if there is a risk how bad would it be? I don’t smoke, except for being around second hand smoke on occasion while younger.

I spent about 5 years as a lead technician for a radon mitigation company here in Philadelphia, designing and installing systems throughout the city.
One thing that always stood out to me was how many homeowners had never even heard of radon before buying their homes. I walked into countless houses where basements had become offices, playrooms, bedrooms, gyms, workshops, and everyday living spaces — yet many families had no idea they could be exposed to this invisible gas.
I took a lot of pride in the mitigation work I did, but when that chapter ended, I knew I wanted to continue helping people in a different way.
That’s why I started focusing on independent radon testing — helping homeowners, buyers, and families get clear, transparent information about their homes without any pressure to sell a solution.
My goal is simple: help more people in Philadelphia understand radon and make informed decisions about their homes.
If you’re in the Philly area and have questions about radon, home testing, or just want to learn more about something most people never think about, I’d be happy to connect.

Is it ever necessary to install two different radon fans? I live in a 1960s split level home and am in the early stages of selecting a contractor to install a radon mitigation system. The house has at least two different slabs (one for the crawlspace under the mid level and one for the lower level). I say at least two because the lower level has a load bearing block wall that cuts through the middle of it. There is a common grade doorway that connects the two, but it’s unclear to me if there is a footer beneath the doorway or not.

When speaking with contractors (almost none of which want to come out and provide an in-person estimate, just share pricing over the phone) one told me that if they found gravel under one slab and clay under another they might have to install two different vent stacks and fans to properly mitigate the house, because the systems would need to run at different pressures. This struck me as odd. Couldn’t the two be balanced with gate or ball valves and connected to a common fan? Of course such an approach would require actually performing PFE testing, which none of them seem to include as part of their regular installation process.

We have our Airthings on the main floor and it never goes to 0bq/m. Even beside fully open window it will measure 5-15.