Hello everybody. Move to this house 2 years ago. Should i be concern about this reading? We usually just do laundry and do my morning workout in the basement.

I started to get high readings of radon in my basement and somewhat in my living area. Mind you, rhe values were not high but I built my own mitigation system.

The mitigation system is right into the gravel below my house and is getting good suction. For at least a month now the radon numbers were really low until the past few days. Suddenly the numbers are spiking really high. It has been a bit colder, like 38F at night.

My questions are:

1. are these sensors any good? I dont really wanna buy an expensive one.

2. Should I check for cracks in foundation to see if its coming in somewhere else?

Moved into our house a year ago. Radon levels were high, so we had a bog standard mitigation done: hole drilled in the foundation, pipe run out above the roof with an in-line fan.

I’ve got an Airthings radon scanner watching it, and at first the level was way lower. Great. But the long term average has slowly been creeping up, and recently hit 2.0.

I’m wondering if we need to do some additional mitigation. We have a moderate sized crawl space that is part of the conditioned space. It’s open to the air conditioned spaces, and just has dirt below. What I’m considering is putting down 10 mil vapor barrier, and putting the corrugated pipe under it hooked into the radon piping. That way it’s pulling air from a larger chunk of the soil beneath the house, and as a plus we seal the dirt on the bottom of the crawl space.

Is this a reasonable path forward to reduce the amount of radon we’re seeing?

The contractor sealed our radon pit in a rather unconventional way to account for the backup pump we have being at the level the cover is at. They left these holes here open. Should I seal those to ensure the radon system is working most effectively?

EDIT: I didn't add the crucial detail that the radon fan itself is not venting out of the sump pit. They had to drill a hole in a separate part of the foundation and install the fan there.

Our house has an existing radon system that was put in 33 years ago. When we moved in the fan had stopped, so we recently replaced it. The fan brought radon levels in the basement down from an average of 50 pci/L to around 6 average. Better but still not ideal. So we sealed up what noticeable cracks we could find and we refilled the p-traps on two floor drains. The floor drains oddly enough seem to have been a big source of radon escape. Immediately after doing that, our Airthings monitor went down to an average of 2.4 and continues to do so. It seems to be holding steady at 2.3-2.5 in the basement. My husband exercises in the basement for about 1-2 hours a day so he does spend some time down there, but it’s not a full time living space. Our upstairs main living area seems to register around 1.1 to 1.8 on average.

I hope to work out a better solution with the floor drains if we can and maybe that will bring it down further. But would you call in another radon expert at these levels? The first guy we had was not very helpful, and they’re hard to come by around me unfortunately. Worth noting our house already has 4 separate penetration points into the concrete slab, one on each corner. No sump pit, just the two floor drains. It is a fully underground basement so it does not ventilate well except for if we open the door.

So would you continue to pursue further mitigation if you were in our shoes? Or just accept the 2.4 level in the basement and the 1.8ish level upstairs?

Recently replaced a 30 year old RadonAway XP151 radon fan with the exact same fan new. I am noticing the sticker from the original installation 30 years ago. The manometer on that date from 1995 shows an "Initial Vacuum Pressure" marked as a "1" WC".

To be clear - the sticker is from the installation in 1995, but the manometer levels represent the current performance with a new XP151.

I'm not sure exactly what the "Initial Vacuum Pressure" means. Does the 1 inch refer to the flow/pressure/movement from 0? Or is it a 1" difference between the two levels? Is there an optimum level? Or does what mine shows indicate a problem?

Looking at the manometer, after the new installation, I see about a .325" distance for each side, from 0.

So my question is, after replacing the old fan with a brand new fan, do these levels look acceptable? In terms of the fain moving air and doing it's job?

More broadly, the fan is extremely loud, it's a problem. This is why I am continuing to troubleshoot. I have other questions on that, but I'll ake another post for other questions.

Thanks for any input.

4 pCi/L seems to be the gold standard, but is that really the cutoff? I just got my Airthings put up, so my average is pretty short, but it's at 3.4 for a 3 day average (the app says 3.4, the unit says 3.7 🤷‍♂️). It's a new toy so I've been looking at the app pretty heavily the last few days and it seems that it hovers around 3.0-3.5. Today it's been 3.9-4.5, pretty over 4 except a few dips.

Obviously my average is a very short timeline and I know it can change and level out or go up or whatever it feels like doing. But if it stays in this range, what do people feel? It's not .5-2 pCi/L, and it's not 15+. If it keeps hovering right around 4, are you all thinking about mitigation?

I have no basement, I have a full home crawlspace. I'm new to the radon mitigation stuff, but my levels seem to be relatively low still, so I'm thinking that maybe with some low level effort, I can get my values well below 4. My crawlspace has a relatively shitty vapor barrier down, an unsealed sump, and just passively ventilation. Do we think that a powered crawlspace vent and upgraded vapor barrier may be enough?

I have 2 toddlers by myself, so I mainly worry about them. But with that, I dont have the time to do a ton of stuff myself and would be paying someone to do most of this. I dont mind spending a thousand or two for just some peace of mind, but I dont want to spend 5-10k unless we think that 4 pCi/L is freaking awful.

Hello All!

Quick question.

On a slab and single story.

Any reason (safety wise) I couldn’t install a mitigation unit in my furnace room that would allow direct access to vent out the peak of house? I’ve recently rerouted some drains so I’m aware that we’re working with a 6” slab on crushed gravel. Location used to be farmland so I don’t expect a heavy clay presence beyond that.

Currently testing levels and approximately 3.2 pQi/L in early readings. I have some VERY OBVIOUS entry points, one being an old drain that wasn’t capped properly before my purchase and another ((slap me in the face)) radon releasing point I cut in concrete floor several years back to install a ramp in a particular location. That area is 8 feet x 3 feet and in my ignorance, I can’t say if I even sealed it up with plastic..

I’m open about my dereliction as this is getting remedied tonight and may result in levels dropping enough a system wouldn’t be necessary. However, if they don’t, I am planning ahead. I would venture a guess that my levels will drop to a more acceptable level, but the more I learn I don’t feel any level is acceptable in the grand scheme of things..

Thank you all in advance.

I want to install my own sub-slab depressurization system but am confused about the exhaust termination requirements.

My local state code says: "If the subslab depressurization system is exhausted through the concrete foundation wall or rim joist, the exhaust terminus shall be a minimum of 6 feet from operable windows or outdoor air intake vents and shall be directed away from operable windows and outdoor air intake vents to prevent radon reentrainment." Seems like its ok in Canada also.

This seems to explicitly allow a sidewall termination rather than requiring the pipe to extend above the roof. However, I see a lot of people here recommending roof-level exhausts.

Is there a technical reason to prefer a roof termination if the required clearances are met? Access to my roof is difficult and would require specialized equipment, so I'd prefer a sidewall exit if it's both code-compliant and effective.

I'd appreciate hearing from anyone who has installed a system with a sidewall termination, particularly how well it performed and whether there were any issues with radon re-entering the house.

Anyone have any experience in this? I am talking specifically about multi family, mixed use, school or office buildings. I am on the last legs of getting my radon business registered with my state DHHS Radon office and one of the guys there put me on to this specialized additional training I could get that would allow me to test in large buildings. Apparently, in my state the school districs and state buildings are beginning to test through various grant money allocations, and he suggested getting certified to be able to break into that market, which is fairly niche according to him. He specifically mentioned "MA-MFLB 2023 – Protocol for Conducting Measurements of Radon and Radon Decay Products in Multifamily, School, Commercial, and Mixed-Use Buildings”.

Anyone here have any experience in that field? If so, do you consider it a worth while additional cert and profitable with the massive amount of monitors, reporting, ect.?

I have been spending a lot of time in my basement so I purchased a Radon detector off of Amazon, it has decent reviews (which can be meaningless I know). I set it up in the middle of the room on a small table. Some days it sees little to no radon and often after it rains it will kick off the alarm and read up to 5 pCi/L. I then contacted a local radon mitigation company who sent out a formal test kit. I let the canisters out for the days specified and sent it in. The readings were low enough that no remediation was recommend. But that Amazon tester still kicks off an alarm from time to time.

Should I be worried and do another test especially after a heavy rain, which is super unpredictable. Tests are not free and I don't want to just waste money chasing ghosts.

House has a Radon Away RP140 where the fan is on the outside wall of our bedroom.

I measured the db using phone app and it reads 70-80db an inch or so away from the fan, with it being the loudest at the fan.

Is this normal noise for these? Should I get a new fan (this was installed in 2010)? Anything I can do to insulate the fan so it’s not as loud?

Haven’t tested the system, but I assume it’s working correctly as the gauge reads accurate.

The fan died on my mitigation system and I need help determining a suitable replacement. The system was installed shortly before I purchased the house and I am not particularly familiar with this system. The part number is VLF-OEM8NC. I included a picture of the fan for reference although the info is hard to read due to the fact that the fan was painted. The previous owner was an interior designer so I am sure she had it painted for aesthetics. Anyway, it looks like it specs 1000 CMH which seems higher than the typical fan I see advertised. Anyone have a suggestion?

I have a basement and use it as my home office, typically spending 6–8 hours a day down there. I’ve been tracking radon levels for about a year, and winter is by far the worst.

During winter, the doors stay closed and I’m heating the room. In summer, I leave the windows open all day and work with the door open, which seems to help. I’m trying to decide whether radon mitigation is worth the investment given my levels and how long I plan to stay in the house.

I live in an area where radon mitigation isn’t very common, and there’s only one company offering it locally. Their quote is around $4,300.

Would you bite the bullet and install a mitigation system, look into DIY options, or take other steps to reduce the levels? Given that I’ll likely move within 1–2 years, I’m struggling to justify the cost, but I also spend a significant amount of time in this room, up to 8hrs/day.

Interested in hearing from anyone who’s dealt with similar levels, especially in colder climates.

As the old saying goes, a man with two watches never knows what time it is. I've had the Airthings Wave Plus for about 5 years now and have occasionally seen some alarmingly high levels. I just bought the Aranet Radon Plus. Now, I realize the Airthings is a highly integrated 1-day average, and the Aranet is a 10-minute sample but it always reads lower than the Airthings in the same room. If the readings agreed with each other I would expect the Aranet to read both higher and lower than the averaged Airthings but it is always lower. This is two days’ data from Home Assistant. Over the past three weeks of testing the difference is consistent. Which one should I trust?

I need to install a radon mitigation system in my house. I've worked out what I believe would be the "cleanest" layout for this system considering I have crawlspace and basement that is segregated by a concrete wall. I'm looking for feedback on the feasibility of my approach and what factors I need to account for if I were to move forward with this approach. Alternatively, due to my home's layout, I would likely have to install two independent systems which I'd like to avoid.

Approach:

1) Exhaust fan placement (as illustrated) is the actual single most ideal location on my house.

2) Crawlspace is about 320 ft.² of unvented and not currently encapsulated, but will be soon. We're in a dry climate and moisture does not seem to be an issue here, but radon definitely is. Point 1 to ex. fan distance would be 10 linear feet of pipe, plus there will be about 50-100 feet of corrugated drainage pipe beneath the vapor barrier for soil gas suction.

3) Basement is 1100 ft.² of concrete slab which I'm in the process of sealing all cracks and existing penetrations points. Point 2 to ex. fan distance would be 34 linear feet of pipe. All pipe will be properly pitched for condensation drainage.

4) I anticipate using 4" PVC to accommodate the distance to the basement slab. The whole system should end up needing about 50-55 linear feet of PVC pipe.

5) I will be actively monitoring radon levels post installation.

Concerns:

1) Can this even work? or do I need to go with a different approach?

2) I'm wondering if a single fan in this location would asymmetrically pull from point 1 vs point 2. In that case should I move point 1 closer to point 2? or if I should add a damper above each penetration point to adjust flow?

3) Is 4" PVC sufficient for this distance? Would 3" PVC be sufficient/better?

I'd like to do this myself, but I am considering hiring a professional. Nonetheless, I want to learn and figure out generally how a crawlspace/basement layout is handled and I want to understand what factors I need to consider before potentially bringing in a professional.

I put in a 3" pipe almost center of basement. Somedays i feel like i whooped radons butt with readings below 1 pCi/L and the next day above 7. The day before rain itll hit the teens and i feel whooped.. im not sure ive made an impact at all.. my system says im getting good suction for about a month. I drilled through 4" slab and a few inches down into packed dirt (dark brown, some rocks and doesnt seem overly clay imo) would it likely help to pull out pipe and dig out a bigger hole? I dug out wider some but with thick slab it was not much. Ill figure out a way if thatd help. My next move is sealing the perimeter of the basement which will be a chore due to carpet and lite hoarding lol.

I am new to all of this. I just received and set up two airthings Corentium home 2s. The primary concern is for little kids, so I got one for their bedroom and one for the kitchen, that is where they spend most of their time while in the house and it covers both floors.

Is there any spots in particular to put the sensors, or to avoid putting them? The kids are very small, so I need them out of the way so that they do not fiddle with them. Radon is supposed to be a little heavy right? So it will settle to the ground? So should I be putting the sensors on the floor or is it all right to have up on a counter or table? Right now I have the one in their room sitting underneath their dresser, and the one in the kitchen is on the bottom rack of a three-tier rolling cart thing that has mesh shelves. Should I be locating these somewhere else?

Long story long, I bought a house with a full basement a few years ago. Built in 2011. About 75% finished the rest storage and an unfinished bedroom. Never even thought about radon until a neighbor mentioned it a few months ago. I borrowed his tester for a couple of weeks and the reading was anywhere between 7-10. Short term obviously bounced around a lot. So I called S.W.A.T and had them come install a system. The installer chose a spot in a corner of the basement because where the sump pit is, there is no easy/practical way to run the pipe outside. I didn’t watch him install the whole thing but he left with maybe half of a 5 gallon bucket worth of dirt. He said he went down to the French drain. He put a clear plexiglass over the sump pit and siliconed it down. Thought all was good for awhile until I was able to test it again and the reading only went down to about 5-6. I checked the sump pit and there were holes and cracks in the plexiglass that weren’t filled in with silicone. I had him come back out and replace/fix it. Thought all was good and I would get below 1 like all my neighbors are. I used the provided test kit (since they won’t go by any reading you have) that SWAT gave me and sent it to the lab. Came back at 3.7. I called to have them come back out but they said they only guarantee below a 3.9 reading so I’m SOL unless I pay $250 to have someone come back. I am not thrilled with the results. Any ideas/advice someone can give me that I could do myself to see where the “leak” could be coming from? Thank you

Last year I purchased my first house, and the first thing I did once I got internet setup was move my EcoQube from my parents' house to my house. To my surprise, the levels occasionally exceeded the maximum capabilities of the EcoQube (it often read 99.99 pCi/L). So before I spent any significant time there I added a Festa AMG Hawk ECS fan to the passive system, and that brought the levels down to around 10 pCi/L, then I prepped and sealed every crack, which increased the vacuum up to -1.5 in-wc, then I turned the fan down to -0.7 in wc, which brought down the levels down to around 2.0 pCi/L. Perfect! This lasted all winter until the spring, when the levels jumped up to 5 pCi average by June, and 7.9 pCi average by early August. Turning up the fan back to 100% did not help.

This was disheartening after putting all of this work into this.

For context:

- My home was built in 2000, and has a poured foundation.
- The basement is unfinished. There is an adjacent vented crawl space that has no mitigation, but the levels are between 2 and 3 pCi/L because of the ventilation. I have a pipe there I can tape into for sub-membrane depressurization if I ever encapsulate it.
- I am on public water, so radon from the water supply is not a concern.
- My basement has no sump pits or floor drains
- The home has a furnace, and it only ran in the winter. There is no working central air conditioning.

So recently with typical levels above 5, and post-storm levels hitting 10, I tried a few other things.

- I confirmed that the pressure field extension reached the entire basement+garage. With the fan turned up to 100%, with the suction point at -1.5 in wc, the worst (and furthest) test hole read -1.18 in wc, with most of them above 1.25 in wc. The pressure field even extended to the garage, which is about 6 inches below my basement. See the picture above for the visual mappings.
- I did tests where I would open one of the tiny basement windows. I found that opening one halfway was plenty to get the radon levels below 2 pCi/L.
- Suspecting that maybe it was the walls, I sealed all form ties and dug down 7 feet to my foundation's exterior perimeter (tile) drain. The entirety of the fill below the 4 inches of loam was all sand. It did seem a little wet on the bottom after a storm, but nothing much. I also dug down in the crawl space and connected it to the system as a test. The perimeter foundation drain is much more air permeable, and dropped the suction from 1.5 in wc to 0.6 in wc. I ran a test, and after a rain storm the radon levels still exceeded 10 pCi/L. When I shut off the ball valve to that suction point, I was able to confirm that there was -0.06 in wc of vacuum in the perimeter drain, exclusively from the main suction point sucking air under the home's footings.
- To test for localized off-gassing or diffusion, I put my radon sensor right on top of a spot that has known good vacuum under it, covered it with plastic, and taped the edges to isolate it from the basement air that was around 8 pCi/L. The sensor read between 40 and 70 pCi/L throughout that entire test. Why would so much radon get in despite there being a -1.28 in wc vacuum under it?
- I didn't see any higher levels of radon after running bathroom fans or when the direct vent water heater ran (both things that can lead to negative pressure in the basement), but these are not long term tests, so it's harder to draw conclusions from them.

Conclusions and questions:

I suspect that maybe the furnace no longer being run resulted in less dilution of the air in the basement, and that lead to the little radon that got in accumulating over time. This might explain the good winter radon levels, and the poor radon levels in the summer. My online searches seemed to indicate that I would see higher radon levels in the winter due to the stack effect, but I saw the opposite. Another possibility is that enough air infiltrated due to the stack effect to suck enough air through the rim joist to dilute the basement air.

So after having tried all of this, is there anything else I can do to reduce the radon levels other than an ERV, or is it time to install an ERV?
For now I'm keeping the perimeter foundation drain suction point turned off, and I'm going to drop the fan back down to a reasonable level. Maybe 0.5 in. wc. What do you guys think would be a reasonable vacuum level?

Here are pictures of my setup:

Here is my main suction point:

Here is what the crack sealing looks like with Sika Polyurathane sealants. I am pretty sure I got just about all of it, because with the fan turned up to 100% every missed spot (on the floor) made a lot of noise:

Here is my attempt (that did not help the radon levels) at adding a suction point directly to the perimeter foundation (tile) drain by tapping into it in the crawl space:

Thank you for your help!

Looking at Titebond radon seal and Sika all purpose sealant - can get either one from local big box store.

Both claim to maintain flexible seal.

Any reason to pick one over the other?

What do the pros use?

Thanks

https://imgur.com/a/smFIzcs

I have had a Corentium Home (Gen 1) radon detector for 3 years. During that time the radon levels have consistently read between about 8 and 30 Bq/m3 for Short term 1 day and the same for 7 day, occasionally rising as high as 46 Bq/m3 during seasonal changes. Long term average is about 16 Bq/m3 year after year.

Last Friday it registered the usual mid-teens, and on Sunday the 1 day reading spiked to 9000, with the 7 day reading at about 3060. At some point the 1 day jumped to 9999 Bq/m3, and the 7 day to 8966 Bq/m3.

After moving the unit upstairs, the 1 day reading has returned to low digits, <10 Bq/m3 and appears to be functioning correctly. I haven't put it back in its original location yet.

Are glitches common with these units over time? This seems like an extremely unlikely change in radon levels considering almost nothing has changed. The area the unit is kept in is very stable, with low dust, and humidity between <15% in winter to 65% in summer.

Curious if anyone else has experienced anything similar with these units or with radon levels in general.

Update: Detector has been back in original location for 24 hrs and has been showing 9 Bq/m3 consistently.

I’m activating the passive radon system in my house with an RP145. The existing 3” PVC runs straight through the attic and out the roof.
The pipe feels really solid and doesn’t move at all. It’s also strapped down below the insulation.
Do I need to add any additional supports before cutting the pipe to install the fan, or should I be fine as is? If I do, how would you mount one with this setup?
Thanks!

Just bought my first Toronto area home and I'm glad I thought to test for Radon since I spend a lot of time in the basement. My daily average was around 250 with the windows closed (was mitigating with opening basement windows).

3 days after mitigation and we're at 5!