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Radon mitigation, sewer penetration seal

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Looking for some advice on a minor radon issue I'm facing. I've tested radon several times over the past two years, including two three-month tests. Radon levels are generally below 4 pCi/l, but one test did spike to 5.5 pCi/l. Radon is only at higher levels in the basement, which is very airtight (new construction, built in 1997). Related to the 5.5 pCi/l test (a 3-month test), where I live near Boston received record winter snow during the test. It is likely the pressure of the snow increased flow of radon into the basement.

Looking to try conservative radon mitigation techniques before considering installing a sub-slab suction radon mitigation system, given my levels are borderline. There is a relatively large penetration in the basement slab for the drain to the city sewer. I inserted a picture below. The penetration is about 2' X 2', a little smaller. This is a prime area for radon to enter the basement in high volumes. I'm considering sealing up this area with hydraulic cement, perhaps putting a foam or rubber sleeve around the sewer pipe to alleviate pressure upon expansion of the cement. I have not been able to find guidance whether this is acceptable under building code, but this was one option a local radon mitigation contractor suggested. He also suggested sealing with 6mm plastic using strapping and wire (couldn't really follow what he was recommending, we only spoke on the phone).

I realize that this is not a true fix for radon, and that radon will seep through any microscopic crack in the slab. I'm simply trying to slow the flow of radon into the home such that natural ventilation (i.e. opening basement windows, there are many) on occasion will keep levels below 4 pCi/l.

Any suggestions or advice is very welcome. Thank you in advance.

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Bite the bullet and have the mitigation system installed now. They will seal that hole as part of the installation. Your house has a problem and you are aware of it. If you go to sell you are required to admit it so why not just fix it right. I think the last sub-slab mitigation system I had installed was a few thousand dollars and that was in the high priced DC market.

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. . . It is likely the pressure of the snow increased flow of radon into the basement.

You betcha. Long periods of rain will have an even greater effect.

. . . This is a prime area for radon to enter the basement in high volumes. I'm considering sealing up this area with hydraulic cement, perhaps putting a foam or rubber sleeve around the sewer pipe to alleviate pressure upon expansion of the cement. I have not been able to find guidance whether this is acceptable under building code, but this was one option a local radon mitigation contractor suggested.

As long as you wrap the pipe in foam sill sealer or something like it, that practice is absolutely acceptable under the building code. Some might even say that it's required (though that would be debatable.)

I realize that this is not a true fix for radon, and that radon will seep through any microscopic crack in the slab. I'm simply trying to slow the flow of radon into the home such that natural ventilation (i.e. opening basement windows, there are many) on occasion will keep levels below 4 pCi/l.

Actually, sealing that hole certainly could be considered to be a true fix for the 4 pCi/l issue. When you sell your house, just tell people that you had levels at 5.5, you sealed the hole, and the levels went down to x.x. Perform a few more 3-month tests and document them. Invite the future buyers to perform their own test. I see no liability there.

If I had the choice between spending $2,000 (the going rate for a sub slab system in my area) and spending an hour of my time along with $20 worth of hydraulic cement, I know what I'd do.

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Thank you all. I am not opposed to installing a radon mitigation system, if conservative measures do not work, that's exactly what I will do. But I feel given the relatively low radon exposure and the fact sealing the penetration will take an hour tops of my time, why not try it.

Jim, you mentioned heavy rains have an even stronger effect on radon levels. Thank you for sharing this, I did not realize this. Up until this summer, the back yard was pitched toward the house and rainwater from the downspouts would flow right up against the house. I have solved this by regrading and installing dry wells into which the downspouts are directlly routed. Perhaps this will further alleviate radon levels.

Thanks again all.

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I'm simply trying to slow the flow of radon into the home such that natural ventilation (i.e. opening basement windows, there are many) on occasion will keep levels below 4 pCi/l.

Opening windows can increase the radon levels; when the wind blows by an open window, it creates a negative pressure in the house which in turn can draw radon gas into the house.

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If you want a good mitigator in Boston area, Eagle Environmental and Chapin Environmental are the guys to contact. I would try sealing that up and doing a re-test.... these open pit things can indeed dump a lot of radon in the house..

Also, you might have some 'stack-effect' issues exacerbating this.. heat loss into the attic space or out the upper story of the house??? If you can work on both things, you might actually knock this down.. As for water in the soil and radon levels... the answer really is 'possibly'...the problem is, it depends on the soil, the footings, house, etc, etc and you can never really really pin that down in the field.. You'd have to go across the river to have MIT live with you for a year to figure that one out.. and I believe .. they are not interested.. :)

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Some people don't go into the basement very often and they close off the HVAC registers. This allows radon to accumulate in the basement.

If you have not yet, you can try keeping the basement registers open and allow the HVAC circulation fan to do its job of pulling return air from the basement and distributing return air from the upper levels into the basement. This balances the air quality more evenly and may keep the radon levels below 4pCi/L on all levels of the home. Some people will run the HVAC fan in the continuous on setting to keep the balance between levels as equal as possible.

Having said that, mitigation systems will certainly reduce the radon levels which reduces risk. Radon mitigation systems can also control moisture so there is added benefit there. But if you're mainly concerned with the 5.5pCi/L and want to reduce it to below 4pCi/L, give what I described above a try.

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Some people don't go into the basement very often and they close off the HVAC registers. This allows radon to accumulate in the basement.

If you have not yet, you can try keeping the basement registers open and allow the HVAC circulation fan to do its job of pulling return air from the basement and distributing return air from the upper levels into the basement. This balances the air quality more evenly and may keep the radon levels below 4pCi/L on all levels of the home. Some people will run the HVAC fan in the continuous on setting to keep the balance between levels as equal as possible.

Having said that, mitigation systems will certainly reduce the radon levels which reduces risk. Radon mitigation systems can also control moisture so there is added benefit there. But if you're mainly concerned with the 5.5pCi/L and want to reduce it to below 4pCi/L, give what I described above a try.

Exposure to radiation and associated health affects are related with the time you are exposed and the level of exposure.

I spend limited time in my basement and much more time on the first and second floor of my house. If it was my home I would rather have higher levels in the basement and lower levels in the rest of the house (of course lowering the radon in the basement is the best option). Running a fan and equalizing the radon level throughout house below 4.0 pCi/L may actually increase the occupants' average exposure which is typically measured in WLM (Working Level Months).

The link between radon and cancer is not a magic black and white switch between 4.0 pCi/L and below. It is a very linear relationship. 4.0 pCi/L was selected as the action level by number crunchers that determined what is considered an acceptable risk. The bottom line is that the more radon exposure over time, the higher the associated risk of lung cancer.

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Some people don't go into the basement very often and they close off the HVAC registers. This allows radon to accumulate in the basement.

If you have not yet, you can try keeping the basement registers open and allow the HVAC circulation fan to do its job of pulling return air from the basement and distributing return air from the upper levels into the basement. This balances the air quality more evenly and may keep the radon levels below 4pCi/L on all levels of the home. Some people will run the HVAC fan in the continuous on setting to keep the balance between levels as equal as possible.

Having said that, mitigation systems will certainly reduce the radon levels which reduces risk. Radon mitigation systems can also control moisture so there is added benefit there. But if you're mainly concerned with the 5.5pCi/L and want to reduce it to below 4pCi/L, give what I described above a try.

Exposure to radiation and associated health affects are related with the time you are exposed and the level of exposure.

I spend limited time in my basement and much more time on the first and second floor of my house. If it was my home I would rather have higher levels in the basement and lower levels in the rest of the house (of course lowering the radon in the basement is the best option). Running a fan and equalizing the radon level throughout house below 4.0 pCi/L may actually increase the occupants' average exposure which is typically measured in WLM (Working Level Months).

The link between radon and cancer is not a magic black and white switch between 4.0 pCi/L and below. It is a very linear relationship. 4.0 pCi/L was selected as the action level by number crunchers that determined what is considered an acceptable risk. The bottom line is that the more radon exposure over time, the higher the associated risk of lung cancer.

I agree with everything you said Steven. Although, a line gets drawn somewhere. In the case of the EPA and radon level, it's 4pCi/L. Below that point there is still risk, I agree. But they say you should consider fixing your home at 4 and above. I bet if you run the fan continually you'll knock the 5.5 down to a 3 and not add significant risk to the upper levels. We are talking parts per million! Is there really any difference between 3 and 5 parts per million? Hardly any at all.

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Some people don't go into the basement very often and they close off the HVAC registers. This allows radon to accumulate in the basement.

If you have not yet, you can try keeping the basement registers open and allow the HVAC circulation fan to do its job of pulling return air from the basement and distributing return air from the upper levels into the basement. This balances the air quality more evenly and may keep the radon levels below 4pCi/L on all levels of the home. Some people will run the HVAC fan in the continuous on setting to keep the balance between levels as equal as possible.

That might help, but not for the reasons that you state. If it were just a matter of stirring the radon around, it might actually harm by making the radon more accessible to people's lungs. The advantage of keeping the fan on is the same as the advantage of using paddle fans - the radon progeny tend to stick to dust, which tends to stick to surfaces in the house - walls, floors, ceilings, furniture, instead of floating around in the air. (To say nothing of a furnace filter.) As long as you can keep the radon on these surfaces for a few hours or days, then it won't harm you. You must inhale (or eat) the particle just when it's in the process of breaking down from one element to another for it to cause you harm. If it's outside your body, it won't hurt you.

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. . . The link between radon and cancer is not a magic black and white switch between 4.0 pCi/L and below. It is a very linear relationship. 4.0 pCi/L was selected as the action level by number crunchers that determined what is considered an acceptable risk. The bottom line is that the more radon exposure over time, the higher the associated risk of lung cancer.

Just to be clear, the 4.0 level was originally chosen not because it was considered safer or an acceptable risk. It was chosen becaue that's the number that the *deciders* thought was reasonably acheivable across the country. It had nothing at all to do with actual risk - it was the lowest number that they thought they could realistically hope for.

Since then, we've been evaluating radon risk in the most bassakwards way imaginable by twisting data into forms that "prove" that 4.0 is a meaninful level. The actual data do not substantiate the conclusions that people have drawn from it. Despite what the radon/industrial complex would have you believe, the 4.0 level is still pretty much a blind stab in the dark.

To further complicate things, people seem to believe that harm from radon is somehow cumulative. It's true that the more you're exposed to it, the greater the risk of harm, but it's more like saying the more bullets you're exposed to, the more the risk of being shot. The effect of the bullets isn't cumulative - it just takes one - and radon is the same. It takes a single decay particle to mutate a single cell of lung tissue to start cancer. Thankfully, our bodies are able enough to deal with these mutations in the vast majority of cases. Heck, one of my lung cells just mutated a few seconds ago - it's either going to die, fail to reproduce, or reproduce without replicating the mutation. In very, very, rare circumstances, it might live and reproduce, and become cancerous. When that happens, it will have been the result of a single decay particle hitting a single cell. Not the result of cumulative exposure.

Now here's the really strange part: You would think that, given this information, the best course of action would be to reduce our exposure to radon as much as we possible can. In reality, we evolved with low-dose background radon all around us, and our bodies not only seem to tolerate it in small amounts, there is a possibility that it provides benefits to us. (Google radiation hormesis) The trick is to figure out how small an amount is benign (or even, possibly, helpful). Unfortunately, no one is really trying to figure this out. They're only looking for data that will bolster the 4.0 status quo, which is probably much too high a number.

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Does radon kill mold?

If so, can asbestos be used to encapsulate the radon mold daughters?

I'm looking for a unified field theory of environmental management.

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...The link between radon and cancer is not a magic black and white switch between 4.0 pCi/L and below. It is a very linear relationship...

I've always thought of it as a crap shoot.

Marc

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...The link between radon and cancer is not a magic black and white switch between 4.0 pCi/L and below. It is a very linear relationship...

I've always thought of it as a crap shoot.

Marc

In my opinion, it's exactly like a crap shoot, with the variation being how often you throw the dice. Throw them 4.0 times per hour and your risk of rolling snake eyes is less than if you throw them 8.0 times per hour or 50.0 times per hour.

And just like craps, it's sillly to worry about the difference between 3.9 times per hour and 4.1 times per hour.

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On 10/23/2015 at 4:02 AM, kurt said:

Does radon kill mold?

 

If so, can asbestos be used to encapsulate the radon mold daughters?

 

I'm looking for a unified field theory of environmental management.

I'm no scientist yet, but I'll just throw some info out. Maybe someone else can answer better.

 

A study done by the University of Iowa found that "resident radon exposure is a significant cause of lung cancer".

 

[Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study, American Journal of Epidemiology, 151(11): 1091-1102, 2000 ]

 

Different studies give different results. Some, like the aforementioned, indicate a significant increased risk of cancer for homes that exceed the EPA's radon regulations.

 

Check out this article ADVERTISING LINK REMOVED Basically it says that most studies done on radon effects are done with miners, who have extremely high exposure. His study was published in Proceedings of the National Academy of Sciences of the United States of America, Vol. 96, No. 1, Jan. 5, 1999

 

I have access to the journal article if you want it. https://beonhome.com/best-radon-detector/

 

Sure, walking to your mailbox in the won't harm you. But if you lived outside in the sunlight all the time your skin cancer risk would go through the roof. Living in a house that has decaying radon you probably had a much higher exposure to it than someone who encounters trace amounts in rocks and dirt. The issue probably wasn't that you're being exposed to it--I'm being exposed to it everytime I help my grandma with her garden--rather it was how much you were being exposed to. The EPA obviously felt it was too much. Whether or not they are right is up for debate.

 

I'm sure the radiation scare could be (and maybe has been) used for scare tactics. But what advantage would the government have for scaring you out of your home, unless they needed the land for a road or waterpipe or something. I gotta run to class, I'll try and find some more info later.

Edited by albertstanley

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Guvmint isn't trying to scare anyone out of their home.  They're just fumbling about, spewing out papers that don't lead to anything concrete, other than the creation of another panic word, paving the way for another revenue stream for a lot of capitalizing folks.

Edited by Marc

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