Doing an inspection on a house with a very high radon result, I surmised that ducts under the slab present possibly an insurmountable radon problem.
And why wouldn't they?
The radon result on a recent home inspected was very high. The ducts under the slab ranged from 8" to 24" deep.
Further, the ducts were rusty or contained mud.
Ducts under a slab typically rust.
And why not? The area is cool and blowing heat is hot.
Condensation will be created and rust will certainly result over time.
But there was an additional problem here, which I see often.
There was mud inside a lot of the deeper ducts.
That means they have been compromised to the point that moisture and mud from under the house is entering the ducts. Turning on the heat also introduces lots of moist air to the house, perhaps too much.
When there is a radon issue in a house, where does most radon come from?
Certainly from the soil, about 70%.
Radon in this house is getting in via the ducts.
And a lot of it!
I called a local radon remediation company I trust and they said they wouldn't touch this one "with a 10 foot pole." They did not see how a radon mitigation fan could be successful given the compromised ducts.
Here is the problem. This house is a 1963 built with cathedral ceilings throughout, and the HVAC system is on one end of the house.
The solution for the duct problem is to close off the compromised ducts and run new ductwork through the house. But there is no attic present that can be used to run new ductwork!
The design of this house makes that impossible.
One solution would be to install the individual room units, but that would be very expensive and the property outside some rooms was not conducive to installing one.
The ducts can't remain because they are introducing huge amounts of humidity to the house, in addition to radon. So they really have to be closed off, and in such a way that they are air tight and no longer admit radon gas! But given the house design a new HVAC system seems very problematic, if not impossible.
So what to do? This wasn't the only problem, but a big one to my clients. After considering everything, they are looking for another house. And I feel for the sellers.
My recommendation: houses are systems! Everything works together. Sometimes one thing works against the other things. And over time a system can become compromised to the point where remedy is extremely difficult, if not insurmountable. A home inspection looks at the whole of the house, and how everything and every system in a house interacts.
AND BUYERS HAVE TO CONSIDER THE WHOLE!
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560