What Is Your Highest Average Radon Concentration

Sometimes it is hard to get levels below 2, especially crawlspaces.

Kevin Moore wrote:Sometimes it is hard to get levels below 2, especially crawlspaces. [/quote

Gotcha; not many crawls here

Clients want a set price so we would have to guarantee below 2 and could cost us more to get it there.

That makes sense.

The highest I have personally had was 265 pCi/l. It took installing 2 fans but I got it down to 0.5pCi/l..The highest I ever heard of in my area was 320

That's unbelievable, wow!

Seller claimed this was professionally mitigated and the buyer didn't want to test...but I can only imagine what the level was in the attic? I recommended that vent go a bit higher...

Jim Hanson wrote:Seller claimed this was professionally mitigated and the buyer didn't want to test...but I can only imagine what the level was in the attic? I recommended that vent go a bit higher...

The radon is burning the soffit! jk

Is it really an issue that it doesn't extend through to the roof? I'm not familiar with how these are installed.

The vent should definitely terminate above the roof line...and based on the stains at the soffit it appears that more than outside air is being drawn in. Imagine how concentrated the radon gas is coming out of that vent....would anyone want that back into the home at any level?

I see your point. I have seen some that are designed this way, but have an elbow that goes over to the gutter and then up to exhaust.

It's moisture staining from the moist air the fan is pulling, they should have just extended the pipe to the edge of the soffit. I hate elbowing around the gutter as it looks dumb and don't usually do it. It makes no difference even though the standards say to go above the roof line.

Kevin Moore wrote:It's moisture staining from the moist air the fan is pulling, they should have just extended the pipe to the edge of the soffit. I hate elbowing around the gutter as it looks dumb and don't usually do it. It makes no difference even though the standards say to go above the roof line.

That's how my neighbor's is: it is just like the one pictured with one more single straight piece that extends to below the gutter.

Jeremiah Anderson wrote:I thought it would be entertaining, and possibly educational, to start a topic to post the highest average Radon Concentration you have found on a Residential Real Estate transaction test. I just had mine recently at 17.8 pCi/l

Had one last year at 24, another last month at 22 pCi/L

Highest I have seen was 48.2 pCi/L. I have heard about 100's around here. My brothers 2 month old house was 26 pCi/L partly because the concrete contractor broke and filled in the underground portion of the passive radon system.

I would say that the split for over/under 4 pCi/L is 50/50

This message was edited 1 time. Last update was at 11/12/2014 11:23 PM EST

55 about 6 years ago. Never seen one anywhere near that one since then.

Incidentally, if you're on the roof and can reach it, always check for air flow out of the top of the system. I just did a home over the summer without any airflow at the top of the radon pipe, but the manometer on the pipe in the basement indicated the system was operating just fine and the fan was operational. The owner and their agent even sent me photos of the manometer in an effort to "educate me" about how to tell if the system was working.

Turns out there was some blockage right above the fan and the fan was overheating.

I have had a reading of 489 pCi/l. It was in a neighborhood where all homes were very high. This was a new construction. The ground is full of ledge or granite. High readings are normal in Maine. I often have readings over 100.