Re: Some radon help. Better understanding pressure system.

On Jan 7, 4:25 pm, ceh <cehup...@xxxxxxxxx> wrote:
So, I've got some radon problems.  Initial level 70.  Sorry for the
length, trying to be clear.
I've contacted _pros_ and they run away as fast as possible and they
haven't offer any suggestions.
I have a new house about 30x70 with a full basement and a footing down
the middle.
I had the radon pipe installed when the house was built, under the
floor is large 2" crushed stone.
The basement has 7' concrete foundation walls, almost all of which is
underground.
I caulked everything.  It seems pretty air tight.
I installed a radon fan and get about 1" of water drop on 1 side of a
manometer.
I guess this is 1" of H20 pressure?  or is it 2"?
Anyway, there is vacuum pressure.  Yet, my radon levels are still
around 20.
I drilled some other 1" holes around the perimeter of the basement to
make sure that air could circulate via the crushed stone.  There is
suction for sure.  If I hold tissue over the hole it is sucked right
in.

So, I'm trying to understand what I should see as far as radon leaving
the sub floor.
Once the fan runs for a few minutes shouldn't I get a vapor lock?  If
I were to go to the exhaust end of the pipe, I should see very little
wind after 10 mins or so correct?  If not, how is it possible for that
much air to get replenished?

Another issue, is at the exhaust in the attic, I didn't want to run it
out of the front roof of my house for cosmetic purposes, so I plumbed
in more 3" pvc that goes up over the ridge and down the other side and
then up again to the final exhaust.

Some bad ascii art to illustrate.

  /\
|/  \
V   |
    |
    |

Could this cause a problem?  Is there an issue where the heavy radon
gas can't get pushed up over this hump?  There is wind coming out of
the exhaust on the roof.  But is the actual radon part staying in the
pipe?

My fan does is rated at 0" h20 @ 160 CFM or 2" h20 at 0 CFM

I installed 2 additional 6" fans 4 feet above the floor.  They tie in
together to the existing 3" pipe.  The new fans are rated 2.5" or
350CFM

Then, My radon levels went up.  So, I'm at a loss, and could really
use some suggestions.

Some have mentioned piping fresh outside air into the sub floor thus
washing the bad air out, but from all the literature I read, you want
vacuum pressure more than anything.  Even when I open the basement
windows and expose the test holes I drilled which are sucking air in
like crazy, I barely see any improvement and usually, the levels go
up.

Thanks for any insight.
Please don't suggest moving... I've heard that a million times.

Radon is nasty gas to try to seal out. It actually decays to
particles while in the house and these particles may be filtered out.

Think about a wall sealer if the basement is unfinished. A gas tight
sealer is epoxy, a good industrial supply house could probably get it
fairly reasonably priced.

If the basement is finished it is a matter of wall coverings. A
replaster with an epoxy coating would be the ticket. Expensive, but
you have a real evident radon issue.

You need to make separate vent ducts for the inside air fans. THe
subfloor slab should be on its own vent duct. A common problem is
making to much air flow into the to small diameter vent duct.
Sometimes a false flow happens and it makes the subfloor flow go
backwards into the slab from the room.

Epoxy the floor and then hope the subfloor system can function. A
better pump would be the first solution. A four inch air pump would
allow a greater margin for error.. You have a huge basement so
possibly install a second subfloor pump.

Rotary roots pumps like in old style superchargers make the rating.
They are expensive though. Fans can not make 4 inchs!

SO epoxy coat, and a new blower, and hope. Then an subfloor extra
blower

.

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