Bruce Hirschler
Hello Everyone- I recently received an email from a homeowner and a mitigator on a difficult mitigation job. This is a home in the mountains of Colorado. Any ideas and/or suggestions you can provide would be greatly appreciated. Here are the details from the homeowner:
We have been trying to reduce the radon in our home for almost 5 months now. First we had the mitigator cut a hole in the lower level floor and install a fan system. It had no effect on the radon lever . The house was built into the mountainside by blasting into the rock resulting in the foundation to be directly on a rock base. We believe that we are not getting any circulation because of this. We filled the hole and went to a fan system bringing in outside air and venting inside air outside. This had a small effect , but not enough to bring readings below 30 to 40. We replaced that unit with a much larger capacity unit . This had a another small effect , but we couldn't get readings below about 25. Next we cut a hole through the wall to the outside on the other side of the house and installed a fan outside blowing fresh air into the bedroom.this had a very small effect. Next we set the air circulating system so it supplied my shop . The shop dropped to below 5 , but as you might expect the readings in the rest of the lower level went up. We then installed a larger fan bringing in fresh air. The shop remained below 5 , and the other areas were well above 10. Do you have any suggestions that might solve our problem ? The house was built in 2003 , and no one informed us of the radon problem here.
Here is the email from the mitigator (who will also be following this string):
.The initial radon level was measured at 70 pCi/l.
The home is 2300 square feet with a finished basement.
Five rooms occupy the basement:
1. a living room with granite fireplace - radon level - if any from granite fireplace was not determined.
2. a shop - which has a wall register that allows heated shop air to enter the garage - which also contains two 100 gallon water storage tanks.
3. a bedroom
4. a storage room
5. a mechanical room
My first attempt was to install a sub-slab system in the basement using a Fantech FR-225 fan.
This fan failed to reduce the radon level.
The under slab conditions are as follows.
1. 4" concrete slab floor.
2. hot water in floor heat.
3. piping rests on 2" stryofaom.
4. the stryofaom rests on approximately 4" of packed sand.
I then installed a Fantech HRV (Heat Recovery Unit) and with various flow configurations have been able to reduce the radon levels to these values in pCi/l
1. Shop - 3.8 pCi/l
2. Living room - 16.0
3. Bedroom - 30.0
With the HRV in operation I installed a Fantech HP 220 fan to bring in fresh air into the bedroom with the following results in pCi/L:
1. Shop - 3.8
2. Living room - 10.0
3. Bedroom - 9.0
My next attempt is to increase the size of the fan bringing fresh air into the basement bedroom.
Please share your wisdom and experience with us so we can fix this home. The homeowner is a very nice patient man, and the mitigator working on the project is a reputable contractor. Chrys
Chrystine Kelley
Colorado Dept. of Public Health & Environment
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