Outdoor Radon is the problem..

[john]

I've been trouble-shooting for 3 years my radon problem...but just recently believe the problem is outdoors and not indoors.

I have an electronic radon monitor that updates reading like every 30 minutes...i've had it as well for about 3 years.

Basically I've sealed everything a 100% indoors for the most part... the foundation was completely sealed of cracks... thick radon plastic on top...and vinyl flooring on top of that..

I realized when I had the windows closed for an extended period of time, the radon levels would eventually fall.. (especially during the winter when the ground is frozen and there is snow everywhere...like it is right now)

During the Spring, Summer, and Autumn...if I opened the windows...the radon levels would slowly increase in the house instead of decrease.... I was pretty baffled by this, so I put the entire electronic monitor outdoors instead of indoors...and the levels remained the same or even rose a bit.

This convinced me that the problem is outdoors and not indoors... I live in the Mountains (Pennsylvania)

And over the 3 year period the numbers generally averaged from 4.0 to

8.0...indoors... but never really got above 9.0 . (currently , since the ground is frozen...the indoor level is 1.9)

So my next question is...what to do now ? I even put the electronic radon monitor outdoors on the 2nd deck (elevated)..and the number were about the same there as well.

So in general, my outdoor radon levels average around 4.0 to 6.0 for the most part... (the 8.0 I mentioned above was an indoor reading dooring the summer)

The house was built in 1992... I bought it in 2005.

any advice is appreciated

john

[greenpjs]

Well, you are right that there is radon outdoors, but the levels you are seeing seem high. Regardless, when the weather is nice and you open the windows, you could be lowering the pressure inside the house due to the air rushing past the windows (venturi effect). That can draw radon into the house from the basement. I am not saying that

*is* definitely happening - just that it could be happening. I had radon levels of 4 to 6 (NE Ohio) and no amount of cualking or sealing made any difference. I had a system installed which sucked air from under the basement floor and exhausted it above the roof. The radon levels in the house dropped dramatically and stayed there. The system consisted of a small fan drawing the air up through a 4" pipe that was inserted through the basement floor. I always wondered if just having the pipe without the fan would have worked. We no longer live there, so I will never know.

[Existential Angst]

What a pita problem.... But, kudos on the excellent sleuthing

What are acceptable indoor limits? Do pre-purchase housing inspections have limits?

Mebbe the solution is to concrete increasing radii around the house, to seal that stuff in? Then, try to make the concrete livable/palatable. Mebbe pour fresh soil over the 'crete?

Or mebbe dig, put boucou radon plastic down, and bring in fresh topsoil.

[Mark]

well no amount of sealing or anything else you can do to your home can lower the indoor level to a level BELOW the outdoor level. So if your indoor level now is close to the outdoor level, there is nothing more you can do..

You can check the calibration of your meter, maybe all the reading are hight... What kind of meter do you have?

Mark

[Stormin Mormon]

You're going to die! Quick! Everyone to the cellar!

More seriously, how about call your local health department. If nothing else, they can send someone out to study the matter. And then use the force of government to make you do expensive things that make the problem worse, at your own expense.

[hrhofmann]

PA is known as an area with high radon levels. Have you tried the meter in another town at least 10 miles away, and have you had the meter calibrated as another poster recommended? It sounds like the house is built on a slab. Is that correct?

[HeyBub]

I think you're going to find Radon anywhere where granite is near the surface.

You could move to south Texas, Louisiana, or Florida. It's mud all the way down.

[ransley]

How do you know the meter is correct and calibrated.

[Limp Arbor]

the ground is

I also installed the fan and it made a huge difference (NW NJ). Fairly easy install that can be done by a DIYer. Make a hole in the floor, run PVC to the fan and through the roof. My understanding is that this works best when there is plenty of gravel under the concrete to facilitate air flow. A manometer installed on the pipe lets you know it is working.

As far as just having the pipe with no fan... This supposedly works if a 'passive' system is installed. This includes many perforated pipes installed in the gravel that all get tied together and vented outside. The slab is then poured over this. If after the fact high levels are detected a fan can be installed on the passive system to further reduce the radon.

As far as the sealed house having lower levels in the winter... In a controlled, sealed environment as temp increases so does air pressure. A warm sealed house will have higher pressure than outside and under the slab. The radon goes elsewhere.

Since your house is relatively new you should have plenty of gravel under the slab. Make a 4" hole and install the fan, you'll be good to go. It is also recommended to seal the slab to the foundation. The company that sold me my fan told me to sprinkle mortar all around the perimeter except the corners and spritz with water to make the seal. When I did the mortar after the fan was installed my manometer reading went up and the radon level went down. The fan should be outside the living space and not near any windows.

[Doug Miller]

And let's inject a little reality here, too. Radon is not the mass killer that many people seem to think it is. According to the EPA, there are about 21,000 deaths per year from radon-induced lung cancers -- 86% of these among smokers.

The odds of a NON-smoker dying from radon-induced lung cancer (approximately

2,900 deaths per year in the U.S.) are lower than the odds of dying from:

- accidental poisoning (27,531 -- only 43 of which were infants or toddlers)

- falls (20,873)

- Parkinson's disease (19,566)

- homicide (18,573)

- aortic aneurysm (13,238)

- viral hepatitis (7,250)

- intestinal infections (6,639)

- accidental suffocation (5,912)

- being injured on the job (5,298)

- being hit by a car while on foot (5,021)

- anemia (3,996)

- accidental drowning (3,579)

- peptic ulcer (3,323)

- fire/smoke (3,109)

[Limp Arbor]

kers.http://www.epa.gov/radon/healthrisks.html>

All true but is does make for good entertainment during home inspections and closing negotiations. In NJ 4.0 pCi/L is the standard threshhold number written into purchase contracts. Below that and the buyer lives with it, above that and the seller fixes or provides a credit. Of course all of this is negotiable but 4.0 is the usual starting point. I think mine was found to be around 7 during the inspection. Last test I did had it below 2.

For anyone else in NJ the DIY test kits that you mail in have an extra NJ specific fee for the Peoples Republic of NJ.

[hrhofmann]

mokers.http://www.epa.gov/radon/healthrisks.html>

Is that because the results are mailed into the state for some sort of record-keeping. What if you have a friend over the border in NY or PA mail the results in for you?

[Tony]

Getting high readings outside is almost impossible. The slightest breeze would blow it all away. Unless you are in one of the worst radon hot spots in the world and it's coming out of the ground all around the house and yard and surrounding hundreds of feet or maybe a mile? Do all the neighbors have lung cancer? How about the previous owner?

Any chance the radon monitor is not made for outdoor use and the readings are way off?

[Caesar Romano]

On Thu, 18 Feb 2010 13:49:37 GMT, [e-mail] (Doug Miller) wrote Re Re: Outdoor Radon is the problem..:

And that doesn't even take into account that the "2,900 deaths per year in the U.S." is probably about a factor of 10 - 50 too high because it is based on the LRNT (Linear Response No Threshold) model of radiation effects in humans. The LRNT model is "conservative" but about as far from reality as you can get.

Excellent post Doug. Thanks.

[Limp Arbor]

The Czars in charge of licensing in NJ charge labs for the number of tests they do per year. The more tests you do per year the more you have to pay the state for your license.

I had my results mailed to a PA relative.

[ransley]

How about its so far out of calibration or isnt accurate anyway, thats why his outdoor reading are high. Its probably a 119$ home owner unit, now look at what pros and governments use , a 4000.00 unit. You really have to wonder why a 4000.00 unit is needed, because it is accurate.

[john]

thanks for the replies , guys..

I'm using a SafetySiren Pro Series 3 Radon Detector... Even though its relatively inexpensive. (under $200) It was very close to the mailed in readings done with the charcoal detector. (on more than 1 occasion too)

Even though the max outdoor readings were only between 4.0 & 6.0 , I didn't both calling the Local Health Authorities or whatever... If it was like 20.0...than yeah.. I would think something was up with the soil.

I gotta do more testing in the spring to make sure... I may even do a mailed in charcoal reading and keep the thing outside the whole time...I guess then I'll know for sure.

But I remember when I used to live in Jersey, they would sometimes close down certain areas because of unusually high levels of Radon in the ground. Like what causes those kinds of situations ? People dump stuff in the ground? or is it naturally occuring ?

I've got Radiant Heating here too ...and they think I have more than 1 slab....1 for the garage area...and another 1 for the house. (garage is connected to the house...but they still think there's 2 slabs total ) so basically nobody around here even wants to touch it. I'm trying to find someone that goes the 'under the foundation' route...with an outdoor fan..but nobody does that either...around here. (Poconos area)

John

[ransley]

gs done with the

the 'under the

The simplest way to check its calibration would be take your meter to a building where its known correct.Your local city or govenment offices are correctly tested. I would call you building inspector, or health dept, even engineer or architect, im sure they could find out their buildings radon level in a phone call and let you leave your meter there for testing. When I see a pro device costing thousands to measure any number of things and a home owner unit of hundreds I know its not going to have a low margin of error or have the quality of build

[ransley]

gs done with the

the 'under the

I just looked at one pro 3 for 130$ online, it says its accuracy is I believe 20% or 1pctl + - That is not accurate but a rough idea. I would think it was good when new but may not be now.

[HeyBub]

It's naturally occurring.

Radon is one of the byproducts of the radioactive decomposition of Uranium, which, in turn, is found in granite. Radon has a half-life of about 3.5 days, so even if it were dumped somewhere, it would be undetectable in a couple of weeks. Uranium, however, has a half-life measured in billions of years, so the rocks under your house will be producing Radon until the sun expires.