OT: Testing for radon gas in your home

[Veloo]

Has anyone ever had testing done for radon gas in the house?

Wondering what folks have done in cases where concentrations exceeded safe levels.

I'm guessing calling a professional as well as purchasing a monitor would both be recommended.
I see a couple of wireless WIFI models as well as non WIFI models that show a digital reading.

Here's a bit of info for those not aware like me:

Radon is a radioactive gas that occurs naturally when the uranium in soil and rock breaks down. It is invisible, odourless and tasteless. When radon is released from the ground into the outdoor air, it is diluted and is not a concern. However, in enclosed spaces like homes, it can accumulate to high levels. High radon levels can be a risk to the health of you and your family.

When radon gas is inhaled into the lungsit decays into radioactive particles that release small bursts of energy. This energy is absorbed by nearby lung tissue, damaging the lung cells. When cells are damaged, they have the potential to result in cancer when they reproduce.

[fmradio516]

thanks for this... something to look out for.

[oldpotatoe]

Has anyone ever had testing done for radon gas in the house?

Wondering what folks have done in cases where concentrations exceeded safe levels.

I'm guessing calling a professional as well as purchasing a monitor would both be recommended.
I see a couple of wireless WIFI models as well as non WIFI models that show a digital reading.

Here's a bit of info for those not aware like me:

Radon is a radioactive gas that occurs naturally when the uranium in soil and rock breaks down. It is invisible, odourless and tasteless. When radon is released from the ground into the outdoor air, it is diluted and is not a concern. However, in enclosed spaces like homes, it can accumulate to high levels. High radon levels can be a risk to the health of you and your family.

When radon gas is inhaled into the lungsit decays into radioactive particles that release small bursts of energy. This energy is absorbed by nearby lung tissue, damaging the lung cells. When cells are damaged, they have the potential to result in cancer when they reproduce.

Son did and they then set up a continuously running vent that moves RADON to outside. If it's high enough, you shouldn't just monitor but remove. It was part of his pre-buy inspection so paid for by the seller.

[Gsinill]

Fairly common issue here in IL, we had this checked in every house we bought.
In the first one, at inspection the levels were way too high and the seller agreed to put in system to get rid of it.
Basically exactly the one OP posted above.
If you already have a sump pump, they can connect to that pit, otherwise they need to drill a hole into your basement floor.

2nd one was fine, current house already had a system installed when we bought it.

[NHAero]

I'm not a radon pro, but as a building performance/forensic engineer I've tested quite a few houses for radon. We have one older accurate instrument (Radstar) that cost +/- $800 that I've used for long term logging. What's important to note here is that levels vary widely. The standard 48 hour real estate test may not capture the real long term average. We also have 2 or 3 Radon Eye RD200 units, which I've tested along side the Radstar, and they're pretty good. +/- $175, use with a phone app. Takes hourly measurements and gives current value as well as average.

I've attached an image of data taken over 8 days by both devices. Note the variation in radon levels!

[wallymann]

yes. we've used those "aircheck" mail-in kits when we sold our old house. and picked up a digital real-time "safety-siren" radon detector when we bought our current moneypit.

for the old house, we had a radon mitigation system attached to our sump. basically, an air-tight cap and a fan system maintains negative air pressure beneath the foundation and evacuates that air above your roof. someone already posted a diagram. this was effective, it brought our levels from north of 4.0 down to below 1.0. cost was $1K.

for the moneypit house, which didnt have a sump system to work with, we just sealed up various entry-points for air into the foundation and also sealed up air leakage from the upper-floors that would draw foundation air into the house. this approach has been similarly effective.

[Veloo]

I'm considering these two models:

Airthings Corentium
https://www.airthings.com/en-ca/home

Safety Siren Pro Series 3
https://www.safetysirenpro.com/canada_en/home/#how

Leaning more on the Corentium because it's battery operated and thinking more flexible with location.
Both are available locally here and I'm not a fan of the two WIFI devices some stores have.

Anyone have experience with these? Accurate? Reliable?

Thanks for the feedback.

[OtayBW]

I'm not a radon pro, but as a building performance/forensic engineer I've tested quite a few houses for radon. We have one older accurate instrument (Radstar) that cost +/- $800 that I've used for long term logging. What's important to note here is that levels vary widely. The standard 48 hour real estate test may not capture the real long term average. We also have 2 or 3 Radon Eye RD200 units, which I've tested along side the Radstar, and they're pretty good. +/- $175, use with a phone app. Takes hourly measurements and gives current value as well as average.

I've attached an image of data taken over 8 days by both devices. Note the variation in radon levels!
I would imagine that variation in soil (or rock) moisture levels, temp, and air pressure might have an effect on the trends? What's an acceptable risk level for radon?

[wallymann]

I'm considering these two models:

Airthings Corentium
https://www.airthings.com/en-ca/home

Safety Siren Pro Series 3
https://www.safetysirenpro.com/canada_en/home/#how

Leaning more on the Corentium because it's battery operated and thinking more flexible with location.
Both are available locally here and I'm not a fan of the two WIFI devices some stores have.

Anyone have experience with these? Accurate? Reliable?

Thanks for the feedback.

i have the safety-siren...it works well!

I would imagine that variation in soil (or rock) moisture levels, temp, and air pressure might have an effect on the trends? What's an acceptable risk level for radon?

the federal standard to take action is 4.0 pCi/liter.

[NHAero]

I found the Safety Siren to be less accurate than the Radon Eye, for consumer level devices, but I don't have as neat of a data plot to show that.

[commonguy001]

Our house was tested as part of the purchase inspection when we were selling. It came back high and they installed a mitigation system. If you do test and decide not to do mitigation, you'll need to disclose it if/when you sell.

[batman1425]

We've tested every house we've bought, and installed mitigation systems in two of them. It's not uncommon and as others have said, highly seasonally variable so don't assume a one time test is reflective of your long term averages.

Can also vary greatly from house to house. Your house could be fine, your neighbor could be a mess. All depends on the ground structures, how the air moves, etc.

The mitigation systems are cheap enough that its a bit of a no-brainer for me. Especially if you plan on spending a lot of time on the lowest level of your home.

[redir]

We have it in our house. When we moved in there was already a system in place but we had to replace the fan last year. Don't mess with it. IF you have it then mitigate it.

[Veloo]

What time of mitigation did you guys put in place besides the sub slab piping that brought concentration down to acceptable levels?

[redir]

What time of mitigation did you guys put in place besides the sub slab piping that brought concentration down to acceptable levels?

The same system that Potatoe shows above and yes the levels are gone. It creates a sink in the system. Basically pressure so all the gas (source) moves to the sink and then gets blown out above roof line. The fan runs 24/7 365 days till it burns out then you replace it. You never turn it off unless maintaing it.

[benb]

It's mandatory here, IIRC you can't sell the house without having it tested and it is always part of inspections.

Ours was OK when we bought our house 10 years ago, we have been thinking about re-testing even though we're not selling, although I'm not sure what natural process would cause a house to go from OK to bad. The whole thing is it's a radioactive gas.. there's not much that would cause it to increase. If it's present it naturally degrades over time, it shouldn't get worse unless something is happening in the geology under the house.

[zap]

We tested the last two houses we purchased.

The house in Maryland was in an area known to have higher levels of radon. We asked the seller to test for radon and the reading came back just above 4.0 pCi/L. The seller had to put in a mitigation system. Multiple testing (over many years including when we sold the home) including one time when the ground was frozen for two + weeks...all readings were below 2.0 pCi/L.

Our current house in NC was tested in January during a cold snap and came back below 2.0. I still went ahead and sealed gaps between the concrete slab and the footing.

[batman1425]

The same system that Potatoe shows above and yes the levels are gone. It creates a sink in the system. Basically pressure so all the gas (source) moves to the sink and then gets blown out above roof line. The fan runs 24/7 365 days till it burns out then you replace it. You never turn it off unless maintaing it.

This - that's the standard system. Cut a hole in the slab, dig out a bucket or two of fill from the hole, put a cap on with to seal it, an inline pump to create negative pressure and draw air trapped under the foundation to the hole and run the exhaust to the roofline. The two that were put in prior to purchase in 2 homes we've owned cost 1k-1.5k installed.

Make sure to get a follow up test after installation to confirm it is working if you don't have a continuous monitor on your unit. The places that did our had a guarantee that if the pump didn't reduce pCi/L below the federal cutoff, they would do additional mitigation till it passed.

[C40_guy]

We've put in two systems. In our area, they run around $1500. Each time I specified no outdoor piping. While it takes a bit more work to run the pipe to the roof internally, it avoids that eyesore of the white 4" pipe exiting the house at basement level, going all the way to the roof peak.

A good installer should be able to work with you to design a system that works.

We test annually using the mail-in kits...which, by the way, have expiration dates...so don't order several to use over time.

[benb]

After my previous post I went and looked up more on Radon.

It's a byproduct of the decay of uranium and thorium. Radon has a half-life of only 3.8 days so it disappears really fast.

But if you've got it then it's coming from uranium & thorium in the ground in your area, those decay over geologic time scale, so there's continuous production of radon.

Sounds like if you've got it then it never goes away but if you don't have much it's not likely to increase.

[echappist]

If my trainer is in the basement (as opposed to ground level), how much more concerned should i be?

[ORMojo]

After my previous post I went and looked up more on Radon.

It's a byproduct of the decay of uranium and thorium. Radon has a half-life of only 3.8 days so it disappears really fast.

But if you've got it then it's coming from uranium & thorium in the ground in your area, those decay over geologic time scale, so there's continuous production of radon.

Sounds like if you've got it then it never goes away but if you don't have much it's not likely to increase.

Yes, that's it. Aside from seasonal variations (generally, higher concentrations in winter), it is a long-term situation.

Fortunately, we live in a low-radon area, but we have still tested every home we have purchased.

1697998609

[ORMojo]

If my trainer is in the basement (as opposed to ground level), how much more concerned should i be?

As much as anything, that would depend on how the air exchange differs in your basement from the upper levels of your house. If there is more limited fresh air exchange in the basement, then there will be an increased risk of higher concentrations of radon.

[R3awak3n]

It's mandatory here, IIRC you can't sell the house without having it tested and it is always part of inspections.

Ours was OK when we bought our house 10 years ago, we have been thinking about re-testing even though we're not selling, although I'm not sure what natural process would cause a house to go from OK to bad. The whole thing is it's a radioactive gas.. there's not much that would cause it to increase. If it's present it naturally degrades over time, it shouldn't get worse unless something is happening in the geology under the house.

same here. when we bought this place they tested it. Apparently some in the basement (wet basement, can't really be used so I don't care) but fine in the house.

[rwsaunders]

What time of mitigation did you guys put in place besides the sub slab piping that brought concentration down to acceptable levels?

Essentially the same system as OP indicated. We built our home in 1999 and I installed a system under the basement slab as a preventive measure, given the history of radon in the region. Pretty simple really and inexpensive, as we made the decision when designing the home.

I’d venture to say that your national or regional health system or building regulatory agency has identified recommended radon mitigation systems for both new and retrofit situations.

[echappist]

As much as anything, that would depend on how the air exchange differs in your basement from the upper levels of your house. If there is more limited fresh air exchange in the basement, then there will be an increased risk of higher concentrations of radon.

Thank you

Also, where did you obtain the map for Oregon, is it from the state? Im wondering if Wisc has something similar

[rwsaunders]

Thank you

Also, where did you obtain the map for Oregon, is it from the state? Im wondering if Wisc has something similar

Good info...PA’s site has informative videos as well.

https://www.epa.gov/radon/epa-map-radon-zones

https://www.dep.pa.gov/Business/RadiationProtection/RadonDivision/Pages/Radon-in-the-home.aspx

https://www.dhs.wisconsin.gov/radon/infocenters.htm

[ORMojo]

Thank you

Also, where did you obtain the map for Oregon, is it from the state? Im wondering if Wisc has something similar

Yes, from State of Oregon

Here is Wisconsin's. (http://wi-dhs.maps.arcgis.com/apps/webappviewer/index.html?id=68f3a3e068854810b626d002ce47aff4) Interactive map, so you can play with it for your locale.
1697998610

Unfortunately, it looks like your area has a relatively high likelihood of high concentrations of radon.
1697998612

[C40_guy]

Sounds like if you've got it then it never goes away but if you don't have much it's not likely to increase.

When we bought a house in 1990, we tested for radon and the levels were quite low. 15 years later we retested and the levels had risen just enough to warrant remediation.

[Jaybee]

When we bought a house in 1990, we tested for radon and the levels were quite low. 15 years later we retested and the levels had risen just enough to warrant remediation.

The standard 48 hour test isn’t a long enough period to capture natural fluctuations in the subsurface. Test a few times if you live in a high-risk area.

[echappist]

Good info...PA’s site has informative videos as well.

https://www.epa.gov/radon/epa-map-radon-zones

https://www.dep.pa.gov/Business/RadiationProtection/RadonDivision/Pages/Radon-in-the-home.aspx

https://www.dhs.wisconsin.gov/radon/infocenters.htm

Yes, from State of Oregon

Here is Wisconsin's. (http://wi-dhs.maps.arcgis.com/apps/webappviewer/index.html?id=68f3a3e068854810b626d002ce47aff4) Interactive map, so you can play with it for your locale.
1697998610

Unfortunately, it looks like your area has a relatively high likelihood of high concentrations of radon.
1697998612

Thank you both; that was very helpful

I think I'll go buy one of those Radon Eye RD 200 units mentioned upthread. Was going to pick up a kit from the county, and have it run while we were away for a few days in March. Obviously, the pandemic changed things.

This thread is a very timely reminder, and thanks to all for the much needed PSA.

[C40_guy]

Thank you both; that was very helpful

I think I'll go buy one of those Radon Eye RD 200 units mentioned upthread. Was going to pick up a kit from the county, and have it run while we were away for a few days in March. Obviously, the pandemic changed things.

This thread is a very timely reminder, and thanks to all for the much needed PSA.

Looks interesting. Post a review after you've run it for a while.

Some good reviews on Amazon, btw...

[OtayBW]

Al these hot spots should be closely associated with igneous, or igneous-derived) metamorphic rock, fwiw.

[binouye]

I'm considering these two models:

Airthings Corentium
https://www.airthings.com/en-ca/home



A friend who works for the State health dept recommended that one, having compared it to the professional units costing several thousand$$. So I bought one, it was super easy to set up and use, and gives both 48hr and 7day moving averages. Fortunately our house's radon values are low enough we don't need to do any mitigation.

[rockdude]

Years ago, I research Radon and wanted to know what the science and research said about death/cancer rate for home owner at different concentration levels. I didn't find anything. Most of the research was done in Mines with very high levels from 70 years ago. Has anyone seen any real research on homes and the actual cancer rates back by radon levels and exposure time? My questions is, what is the real risk that has been validated by science?

[C40_guy]

Years ago, I research Radon and wanted to know what the science and research said about death/cancer rate for home owner at different concentration levels. I didn't find anything. Most of the research was done in Mines with very high levels from 70 years ago. Has anyone seen any real research on homes and the actual cancer rates back by radon levels and exposure time? My questions is, what is the real risk that has been validated by science?

@rockdude Here's a pretty detailed discussion (https://www.ncbi.nlm.nih.gov/books/NBK143219/) of the question you raise.

Take a look and let us know if you think the studies have identified a causal relationship.

[OtayBW]

Years ago, I research Radon and wanted to know what the science and research said about death/cancer rate for home owner at different concentration levels. I didn't find anything. Most of the research was done in Mines with very high levels from 70 years ago. Has anyone seen any real research on homes and the actual cancer rates back by radon levels and exposure time? My questions is, what is the real risk that has been validated by science?
May or may not be what you're looking for, but here's a relatively recent link that may help. The references may be helpful. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211050/

[NHAero]

As I wrote above, we've used these for a couple of years and validated against a professional grade instrument.

Looks interesting. Post a review after you've run it for a while.

Some good reviews on Amazon, btw...

[NHAero]

TL;DR warning!

As a building engineer, I have colleagues throughout North America, including some of the most prominent indoor air quality experts. I'd say that there isn't 100% consensus - I have one very respected colleague who is a contrarian about radon being as big of an issue as it is made out to be - but there's a pretty high consensus that it is a real issue.

That said - my field includes very low energy use buildings, which are very airtight, with mechanical ventilation, which is why I've been interested in radon. Soil gases entry into buildings depends on the pressure gradient and direction - mitigation systems depressurize the building sub-slab. I've noticed that in houses of normal air tightness, radon levels can be very roughly correlated with the weather. As one of my clients said, after we looked at the data from his house, the radon level shoots up when the ferries are cancelled (really windy days, Martha's Vineyard). Interesting to me is the fact that I know the air change rate in this house is higher on those days, from wind pressure, but that whatever the radon transport driver is, it's stronger than air change rate. This has been validated in general terms, both for radon and other pollutants - source strength is more important than air exchange rate.

Another observation that relates to house air tightness. In typical houses here in the northeast, if the radon level in the basement is X, it's common for the radon level on the first floor to be +/- half of X. In really tight houses, the level on the first floor tends to be much less than the basement level. At my house (140 CFM50 for blower door afficianados) my bedroom on the first floor is 8 to 10 times lower than the basement radon level. I don't spend much time in the basement - I do work on bikes down there, that's about it - so I haven't installed a mitigation system. I know that it's likely I'll install one when I go to sell the house. The reason I put it off is that I want the house to be balanced in terms of pressure, because I have a wood stove that i don't want to backdraft. Radon mitigation fans tend to run houses negative relative to outdoors, and the tighter the house, the more negative.

Current guidelines include placing the fan outside the pressure boundary of the house. If you have an unconditioned attic, that's a good place for the fan. The reason is that any leaks on the downstream, pressure side of the fan bring concentrated radon into the house! If the house is all cathedral ceiling with no attic, the fan ends up outdoors.

Years ago, I research Radon and wanted to know what the science and research said about death/cancer rate for home owner at different concentration levels. I didn't find anything. Most of the research was done in Mines with very high levels from 70 years ago. Has anyone seen any real research on homes and the actual cancer rates back by radon levels and exposure time? My questions is, what is the real risk that has been validated by science?

[NHAero]

True. What's interesting to me, having moved ten years ago to Martha's Vineyard, is that the rock is pretty far down here (my well is in a sand aquifer where the water level is over 70 feet down) and yet there is still plenty of radon.

My conclusion is that experts still don't understand the mechanisms that cause the fluctuations in radon levels in buildings. I monitored hourly radon levels, pressure between the basement and outdoors, and outdoor temperature, and plotting them all it seemed that temperature was a closer curve than pressure - which is not intuitive at all.

Al these hot spots should be closely associated with igneous, or igneous-derived) metamorphic rock, fwiw.

[ORMojo]

TL;DR warning!

All this talk about "airtight" and "gases" and "air exchange rate" and much more will forever make me associate your NHAero user name with different impressions than previously! :D

[echappist]

TL;DR warning!

As a building engineer, I have colleagues throughout North America, including some of the most prominent indoor air quality experts. I'd say that there isn't 100% consensus - I have one very respected colleague who is a contrarian about radon being as big of an issue as it is made out to be - but there's a pretty high consensus that it is a real issue.

That said - my field includes very low energy use buildings, which are very airtight, with mechanical ventilation, which is why I've been interested in radon. Soil gases entry into buildings depends on the pressure gradient and direction - mitigation systems depressurize the building sub-slab. I've noticed that in houses of normal air tightness, radon levels can be very roughly correlated with the weather. As one of my clients said, after we looked at the data from his house, the radon level shoots up when the ferries are cancelled (really windy days, Martha's Vineyard). Interesting to me is the fact that I know the air change rate in this house is higher on those days, from wind pressure, but that whatever the radon transport driver is, it's stronger than air change rate. This has been validated in general terms, both for radon and other pollutants - source strength is more important than air exchange rate.

Another observation that relates to house air tightness. In typical houses here in the northeast, if the radon level in the basement is X, it's common for the radon level on the first floor to be +/- half of X. In really tight houses, the level on the first floor tends to be much less than the basement level. At my house (140 CFM50 for blower door afficianados) my bedroom on the first floor is 8 to 10 times lower than the basement radon level. I don't spend much time in the basement - I do work on bikes down there, that's about it - so I haven't installed a mitigation system. I know that it's likely I'll install one when I go to sell the house. The reason I put it off is that I want the house to be balanced in terms of pressure, because I have a wood stove that i don't want to backdraft. Radon mitigation fans tend to run houses negative relative to outdoors, and the tighter the house, the more negative.

Current guidelines include placing the fan outside the pressure boundary of the house. If you have an unconditioned attic, that's a good place for the fan. The reason is that any leaks on the downstream, pressure side of the fan bring concentrated radon into the house! If the house is all cathedral ceiling with no attic, the fan ends up outdoors.

Thanks for taking the time to share your insight

[C40_guy]

TL;DR warning!


I know that it's likely I'll install one when I go to sell the house. The reason I put it off is that I want the house to be balanced in terms of pressure, because I have a wood stove that i don't want to backdraft. Radon mitigation fans tend to run houses negative relative to outdoors, and the tighter the house, the more negative.

Interesting. Ideally the slab is fully sealed except for the radon pipe penetration, so there shouldn't be *much* air pulled down through the slab and then out, right?

Otherwise, you'd risk poor performance from an oil or NG heating appliance that's typically located on the same level.

If your woodstove is on the first level, you will probably get plenty of make up air from the usual sources...if not you could always install an OAK.

Our house is pretty tight...I'm not sure what our CFM test showed after topsealing in the attic and some other minor steps. If I'm not careful when I first light our woodstove (insert) I can get a cold, smoky downdraft. Cracking a window helps. Once the fire is established I get a good clean burn, which means the stove is getting enough air from somewhere. I think for the stove its the cold flue creating the downdraft rather than the stove being starved for air.

Gas cooktop and clothe dryer operate normally. We also have an HRV for the first floor...the people doing the insulating work, (partially underwritten by Mass-Save), required that.

I might pick up one of those electronic radon monitors to see if woodstove (or boiler use) pulls air through the slab.

[Spaghetti Legs]

Good discussion. We've had radon testing done at all of home sales and purchases over the years. It's never been much of an issue until our current house where the level was 12. Seller installed a mitigation system like that pictured by Old P and levels remeasured I believe < 1.

One point of consideration if you're going to get a mitigation system: Mine has an exhaust fan on the outside of the house just above ground level. It's pretty quiet to stand next to it but the sound transmits up the exhaust pipe which runs next to our bedroom window so there's a constant hum which is kind of annoying. I've thought about running it intermittently such as turning it off (has it's own breaker) at night. I don't think it would have that much effect on radon levels but might shorten the life of the fan as I hear it's better to just let them fun 24/7. Point being, if you're getting a system, run the piping somewhere you don't plan on extended sitting quiet time.

[C40_guy]

One point of consideration if you're going to get a mitigation system: Mine has an exhaust fan on the outside of the house just above ground level. It's pretty quiet to stand next to it but the sound transmits up the exhaust pipe which runs next to our bedroom window so there's a constant hum which is kind of annoying. I've thought about running it intermittently such as turning it off (has it's own breaker) at night. I don't think it would have that much effect on radon levels but might shorten the life of the fan as I hear it's better to just let them fun 24/7. Point being, if you're getting a system, run the piping somewhere you don't plan on extended sitting quiet time.

As mentioned above, our system was run internally and the fan is in an unconditioned space next to our bedroom. We have a similar issue with the hum...it's quiet, but it's there. My short term solution was to wrap some insulation around the fan and pipe, which reduced the noise transmission somewhat.

My next step is to apply some DynaMat to the pipe, to further dampen the vibration. I haven't gotten to it yet as the insulation cut most of the noise, and I don't happen to have enough DynaMat on hand to really do the job. (What I have is left over from an automotive interior swap). DynaMat might be a better solution for you too, given the outside location of your fan.

[Louis]

The standard 48 hour test isn’t a long enough period to capture natural fluctuations in the subsurface. Test a few times if you live in a high-risk area.

In my experience radon levels are hugely influenced by the weather outside.

The folks who tested my house before I bought it showed me the time-history plot of the levels over time and there was a big increase when a storm system came through.

Here's one explanation:

http://www.lifetimeradon.com/GasRemovalInformation/Weather-Radon-Testing

[NHAero]

You both might also look carefully at whatever the mounting hardware is that holds the pipe. Putting a piece of hard rubber in between the base of the hardware and the building might help. We've had similar issues with wall-mounted hardware for minisplit heat pumps.

As mentioned above, our system was run internally and the fan is in an unconditioned space next to our bedroom. We have a similar issue with the hum...it's quiet, but it's there. My short term solution was to wrap some insulation around the fan and pipe, which reduced the noise transmission somewhat.

My next step is to apply some DynaMat to the pipe, to further dampen the vibration. I haven't gotten to it yet as the insulation cut most of the noise, and I don't happen to have enough DynaMat on hand to really do the job. (What I have is left over from an automotive interior swap). DynaMat might be a better solution for you too, given the outside location of your fan.

[Spaghetti Legs]

You both might also look carefully at whatever the mounting hardware is that holds the pipe. Putting a piece of hard rubber in between the base of the hardware and the building might help. We've had similar issues with wall-mounted hardware for minisplit heat pumps.

Good ideas, thanks to both of you. C40_Guy, here’s a gratuitous pic from yesterday’s ride on my C40

[C40_guy]

Good ideas, thanks to both of you. C40_Guy, here’s a gratuitous pic from yesterday’s ride on my C40

Sweet!

I will probably be getting my C50 out this weekend, for its first ride of the year...and its first ride since over a year ago.

My C40 was retired and sold about 8 years ago... I need to finish building my Master and Prestige, and get the bikes those replaced sold!

[C40_guy]

You both might also look carefully at whatever the mounting hardware is that holds the pipe. Putting a piece of hard rubber in between the base of the hardware and the building might help. We've had similar issues with wall-mounted hardware for minisplit heat pumps.

I think my fan is already somewhat isolated, but I'm not sure. I'll take a look. It's a good idea!

[mdeth1313]

Son did and they then set up a continuously running vent that moves RADON to outside. If it's high enough, you shouldn't just monitor but remove. It was part of his pre-buy inspection so paid for by the seller.

This - found during inspection so the seller had to remediate. Best part was they wanted to give us a certain amount of money and let us deal with it AFTER it was sold. Naturally, we refused. Their radon problem could have become our radon problem. Fortunately, the system worked perfectly and is still going strong.

[saf-t]

TL;DR warning!

Current guidelines include placing the fan outside the pressure boundary of the house. If you have an unconditioned attic, that's a good place for the fan. The reason is that any leaks on the downstream, pressure side of the fan bring concentrated radon into the house! If the house is all cathedral ceiling with no attic, the fan ends up outdoors.

Same principle applies to virtually all exhaust ventilation for contaminant control- you never want the bad stuff to be forced out of a leaking duct into an occupied space. Sucking clean air into a leaky duct is no problem.

[OtayBW]

True. What's interesting to me, having moved ten years ago to Martha's Vineyard, is that the rock is pretty far down here (my well is in a sand aquifer where the water level is over 70 feet down) and yet there is still plenty of radon.

My conclusion is that experts still don't understand the mechanisms that cause the fluctuations in radon levels in buildings. I monitored hourly radon levels, pressure between the basement and outdoors, and outdoor temperature, and plotting them all it seemed that temperature was a closer curve than pressure - which is not intuitive at all.Radon is thought to be retained by physisorption, ideally on high surface area adsorbents such as silica gel or activated carbon. Your sand aquifer and overburden material may be good for filtration of residential/municipal sewage and etc., but possibly not so good (too coarse crystalline) for adsorbing/immobilizing radium or uranium isotopes....
Just spitballing...

[jamesdak]

Son did and they then set up a continuously running vent that moves RADON to outside. If it's high enough, you shouldn't just monitor but remove. It was part of his pre-buy inspection so paid for by the seller.

Yep, this is basically what I had installed in my current home. Been running 15 years trouble free.

[C40_guy]

This - found during inspection so the seller had to remediate. Best part was they wanted to give us a certain amount of money and let us deal with it AFTER it was sold. Naturally, we refused. Their radon problem could have become our radon problem. Fortunately, the system worked perfectly and is still going strong.

We did it the other way round. I wanted to be able to select the installer and the approach.

[NHAero]

Agree. I got $1500 off the purchase price, and someday will install a system.

We did it the other way round. I wanted to be able to select the installer and the approach.

[zap]

edit

In my experience radon levels are hugely influenced by the weather outside.

I was told that winter time when the ground is frozen is best to capture peak radon levels. This is also when many of us are in the pain cave breathing viciously hard.

[NHAero]

I think you're right - certainly no resistance to gas flow.

Radon is thought to be retained by physisorption, ideally on high surface area adsorbents such as silica gel or activated carbon. Your sand aquifer and overburden material may be good for filtration of residential/municipal sewage and etc., but possibly not so good (too coarse crystalline) for adsorbing/immobilizing radium or uranium isotopes....
Just spitballing...

[Kyle h]

My wife and I bought our home as a cash quick sale, knowing it was basically going to need an entire guy and redo and thus didn’t have a typical inspection done prior.

Because of this thread I bought a RadonEye sensor and plugged it in this week. Granted it’s been cold this past week but our numbers are scary. Averaging 5.2 with spike as high as 6.3. Our workout room is in the basement and now I’m actually a bit bothered by overlooking this. Many thanks to everyone here posting.

[echappist]

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