On Feb 17, 8:34*pm, wrote:
On Wed, 17 Feb 2010 20:15:59 -0500, "john"





wrote:
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

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.



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.