Radon Mitigation System

[Todd Bosse]

Hi all.

I was wondering if anyone has ever used a radon mitigation vent fan to remove stagnant air under an old house?

I recently purchased an old house (built in 1898) in Chicago and there is a very distinct odor throughout the house, especially in the basement. The listing agent told us that the previous tenants of the house had a LOT of cats so I assumed the smell was from the animals. After lots of cleaning and airing out, the smell was gone. But, it returned after the house was closed up for a while again with no ventilation. To make a long story kind of short, my electrician was giving me a consultation the other day and told me that he recognizes the smell from working in many old houses. He told me that it's not pet odor but stale and stagnant air under my subfloor. He told me that simply installing a radon mitigation vent from the dirt/gravel floor under my house to the outside would work wonders in ridding the house of that smell. Of course, he told me it was very easy to do but didn't offer to help.

Has anyone ever installed one of the systems before. I've done some research and it doesn't look that complicated. But things are always more complicated than they seem. There are so many models on the market and it's hard to know what the proper airflow should be since it's hard to know what's exactly under such an old house.

I'd love to hear from anyone that has installed one of these systems themselves. Any advice and suggestions will be much appreciated.

Thanks in advance!!

Todd

[Pat Germain]

Installing such a vent may help. Or, it may treat the symptom and not the problem. I think it would be a good idea to find out what's going on in your basement. It's very common for basements to build up excess moisture under the subfloor. It's also very common for people (previous owners) to ignore problems or attempt cheap fixes.

Does your basement have a sump pump? It is working properly? Is there water puddled unerneath the floor or is it muddy? Check it out. It may save you big problems in the long run. :)

[Bryan Rocker]

Agreed, radon/crawl space vents can and do remove both moisture and stale smells. I would be willing to bet you have a moisture problem. We install crawl space vents in our habitat houses. You might find that after many years that the dirt next to your foundation is not moving water away any more.

[Jeff Kerr]

Tod,

We had a house that was built with a vent pipe from day one for that reason. Our area was having a lot of issues with Radon and the builder just started doing it from day one. It consisted of PVC pipe that went from the gravel below the concrete basement floor up through the house and out the roof. In the attic was a place to ad a inline fan for powered venting if needed.

Our current house does not have the vent in it but as part of the real estate transaction we had the house tested. (Sellers paid).

Pretty simple. Since ours is a ranch with basement they sent us 2 testers by mail. Put them out as directed for a period of time and then send them back to the lab for processing. (They kinda looked like ant traps)

Later you get a report in the mail.

Before I went to the expense of mitigation I would have the house tested.

[Kent Fitzgerald]

Greetings from the Radon State!

First thing: I understand that you aren't explicitly concerned with radon, but I'd suggest doing radon tests before and after you change anything. Cook Co., IL is considered to be a moderate risk area for radon, and it would be good to know what level you're starting with, and whether the system makes a difference (an improperly designed or installed system could make radon levels worse).

I haven't installed a radon system myself, but I watched the process pretty closely when our house was done. The challenging part of the job was routing the 4" PVC pipe unobtrusively from the basement, through a crawl space, into the garage, through the garage attic (where the fan is), and out the garage roof.

In the dirt-floor crawl space, the installers put a heavy plastic membrane over the dirt and sealed the edges of the membrane to the foundation walls with adhesive. A 4" suction pipe passes through the membrane and is sealed with a hose clamp. A similar setup is shown in Figure 4 of this link: http://radon.oznet.ksu.edu/factsheets/KS%20DIY%20Mitigation%20Drawings%20Fact%20Sheet.pd f (http://radon.oznet.ksu.edu/factsheets/KS%20DIY%20Mitigation%20Drawings%20Fact%20Sheet.pd f)

I think a sealed membrane is key; without it, you'll probably just draw house air through the floor and into the crawl space. In cold temps (ever get those in Chicago?), this could actually worsen moisture problems, as the warm interior air hits the cold crawl space and condenses.

Will a radon system help with your subterranean moisture / odor problems? I'm not sure. We were told that our radon system would help remove moisture as a side benefit. Our basement and crawl space are dryer now, but I think that's mostly due to other improvements to drainage and grading.