fan for radon mitigation

[brit1]

I have had two proposals for mitigation after testing and finding radon levels above 4 in both basement and family room. One involves mitigating through the basement wall to remove radon from basement and then waiting to see if that takes care of radon in what was a garage but is now a family room and is built on a slab so is not over basement. Second proposal will include family room area and vent up through a closet and into attic. That worries me with fan going thru attic is if something went wrong wouldn't we have an incredible dose of radon coming up through the house vs venting out through basement? So I would really appreciate some opinions here. The first proposal is by someone in the field who has lots of great reviews and the second one doesn't have so many reviews but is well recommended.Both are licensed etc here in MD. Thanks for input. brit

[Bill Kibbel]

They should be installing the fan outside of the living areas of the home, resulting in all piping "inside" is under negative pressure. If the piping fails downstream of the fan in an attic, the "incredible dose of radon" would likely dissipate in the (hopefully) vented attic and not into the actual living areas of the home.

Be sure to get a post mitigation clearance test from a testing firm not affiliated with the installer.

[Mark P]

Do not vent into the attic, have the pipe pass through the attic and vent outside above the roof line.

[Les]

Brit,

did you do the screening? Are you the new owner of house? Bill and Mark have made good comments.

[brit1]

yes forgot to say they would vent it outside of roof through attic so would that be ok? the pipe would come up through a closet from the basement up into attic. I just thought that if something happened to the pipe or fan it would back draft into the attic and down into living area We have lived here many years and stupidly never tested for radon so am very distressed over it all. I was concerned whether just piping out of basement would be safer. We had originally tested with a home kit and then when it was high I purchased professional kits and placed one in family room and one in basement and they were there for a week.

[Mark P]

Yes up through the attic would be just fine and is how I would have it done.

[Nolan Kienitz]

I don't have to deal with radon in Texas (either as a homeowner or as an inspector).

That being said ... when I lived in Colorado (SW of Denver in the foothills) my home had a basement with a floating floor and had a radon mitigation system installed with pipe that ran up a chase through attic and out the roof. Fan was part of the installation as well.

It was in the property when we bought the home and just an element that was expected in homes in Colorado.

It worked very well.

[Erby]

You tested both areas. Both areas were high. They're separate foundation systems.

Put a suction point in both foundations and then quit worrying about it for a few years until it's time to test again.

As Bill said: "get a post mitigation clearance test from a testing firm not affiliated with the installer."

[Charlie R]

Does the area on slab have under-slab duct work for your HVAC? If it does, then if there are any holes or cracks in the ducts, then you can have radon entering the ducts directly and the one mitigation system in the basement won't help.

Radon mitigation piping should, by EPA standards, extend at least 12 inches above the roof line. Piping itself can run up through the home, attic, and roof or just go outside and up above the roof. As already pointed out, get a post-installation test done by a source other than the contractor. Some contractors will have an independent person come by and test (EPA requires a minimum of 24 hours from the end of the installation and the beginning of the test) so ask if this is included in the proposal pricing.

Proper testing is in both the basement and the on slab area.

[brit1]

thanks for all the input. brit

[John Dirks Jr]

Some houses can be tricky to mitigate depending on various things. Some of them are structure layout and ability of the medium/substrate beneath the slabs to communicate effectively towards the suction point.

When situations are questionable, a good mitigation contractor will do diagnostic testing of the proposed plan prior to beginning the installation. The goal is to see how well the sub slab materials can communicate towards the planned suction point. Sometimes the results of the diagnostics require more than one suction point.

In some cases it takes months before the mitigation efforts reach their maximum ability. This is because the vacuum in the sub slab also pulls moisture out. As it pulls moisture out of the medium over time, the ability for air to pass through increases and the mitigation results gradually improve.

Make sure the contractor has a written contract that includes language guaranteeing to reduce the radon levels to at least below the EPA action level of 4 pCi/L. That way, hopefully their on the hook to solve the problem - whatever it takes.

You can check your state at this link to find NEHA-NRPP certified professionals. http://neha-nrpp.org/radon_mitigation_service.shtml