What I'm Seeing Now

head_left_image

Ducts Under The Slab Possibly Present An Insurmountable Radon Problem

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

www.jaymarinspect.com


Comment balloon 56 commentsJay Markanich • October 25 2013 04:29AM

Comments

I have never even heard of ducts running under the concrete slab Jay; it sounds like the sellers are going to have a difficult time in selling this home.

Posted by Tom Arstingstall, General Contractor, Dry Rot, Water Damage Sacramento, El Dorado County - (916) 765-5366, General Contractor, Dry Rot and Water Damage (Dry Rot and Water Damage www.tromlerconstruction.com Mobile - 916-765-5366) almost 5 years ago

I was told yesterday that the sellers don't think there is a problem, and that I have identified something outside my purview Tom.

I'm not so sure about that ...

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

There are approx. 5,000 such homes in PG County with this identical structure. 

Actually, Levitt built about 12,000 homes on concrete slabs in Bowie MD, but the duct systems were all above ground, most in bulkheads.

However, the radon levels in Bowie are generally lower than in Northern Virginia. 

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate) almost 5 years ago

Good morning Jay,

Radon becoming more and more in our area since they have started testing. Not to many slabs here so the ductwork would not be a problem.

Make yourself a great day.

Posted by Raymond E. Camp, Licensed Real Estate Salesperson Greater Rochester (Howard Hanna Real Estate Services) almost 5 years ago

I must say that I have never seen duct work under a concrete slab. Bad design! I guess there's a reson they stopped doing it.... they did stop doing that, right? With cathedral ceilings, one could go with that exposed duct work look we see in commercial buildings and paint them... just a thought.

Posted by Fred Hernden, CMI, Albuquerque area Master Inspector (Superior Home Inspections - Greater Albuquerque Area) almost 5 years ago

These were popular in the 60s Lenn.  I see them all the time in NOVA.  But they do present problems!

Looking at the radon maps your area is radon suspect Raymond!

Like Lenn says, it's popular here Fred.  And I don't like it.  It is rare that there aren't real problems.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Wow! This is a terrible situation for homeowners who are trying to sell. In Charlotte overly high radon levels become a material fact that needs to be disclosed. And if they remain you can't sell the home and you endanger your own family by living in it. Wow!

Posted by Nina Hollander, Your Charlotte/Ballantyne/Waxhaw/Fort Mill Realtor (Coldwell Banker Residential Brokerage | Charlotte, NC) almost 5 years ago

I don't know how it's handled here Nina.  But typically there is no disclosure.  I think the agent is supposed to disclose, but don't quote me on the radon thing.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Yikes. Since there's tall ceilings, they could really make it nice and ditch the forced air and put in a Warmboard radiant heat system over the concrete floors. Yes, it's not cheap but makes the home way more comfortable and then it might be worth more too. At least they could sell it. 

Posted by Charlie Dresen, Steamboat Springs, CO e-Pro (Steamboat Sotheby's International Realty) almost 5 years ago

The house is on two levels, both slabs, one level not much deeper than the other Charlie.  So your solution might require two systems!

But you're thinking outside the box! 

What about AC?

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Thats why it is so important to get a GOOD inspection of the premises. Time reveals many things

Posted by Richie Alan Naggar, agent & author (people first...then business Ran Right Realty ) almost 5 years ago

And, Richie, take all the information together to determine a whole picture of the house!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Jay, what a mess.  I think for these sellers the best option is Fred's idea of exposed ductwork, similar to a loft. Not the greatest fix for sure.

Posted by Tom White, Franklin Homes Realty LLC, Franklin TN (Franklin Homes Realty LLC (615) 495-0752 or www.FranklinHomesRealty.com) almost 5 years ago

Wow, Jay. Those poor people. If they don't want exposed ductwork, it looks like the house will have to be lifted & a basement or crawlspace built or the whole thing destroyed...

Thanx for the graph, I never knew where radon came from... we don't hear about it much in Canada.

Posted by Peg Barcelo, The FlufftasticStager from Summerland, BC (Fluff My House! Home Staging Inc. 250.486.6369) almost 5 years ago
That's a pretty ugly situation Jay. Glad this wasn't a common construction practice in our market.
Posted by Bill and MaryAnn Wagner, Jersey Shore and South Jersey Real Estate (Wagner Real Estate Group) almost 5 years ago

Thanks Tom.  That may be a solution, and there is a small duct system out there, but given the design of the house they would not be pretty, if possible at all.

For my clients, this is a moot point as they have walked to find another house.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

This is not common here Bill, but present.  And ducts under the slab always present problems!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Possibly multiple suctions points with large radon fans would mitigate it sufficiently.  There has to be an easier way!

Posted by Marc McMaster, Putting my clients before myself (RE/MAX Centre Realty) almost 5 years ago

As you know Marc, radon mitigation uses a single tube through the slab and sucks air from under the house.  In this case it would not be possible - there are two different slabs and ducts under each.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Radiate heat with the pex tubing in the cement, if not drained... expansion could be devastating too...

Posted by Andrew Mooers | 207.532.6573, Northern Maine Real Estate-Aroostook County Broker (MOOERS REALTY) almost 5 years ago

Sounds like a very expensive fix, and no ideal one, but I agree home buyers need to look at the whole and that is why they need a home inspection from someone who knows and has experience like you Jay.

Posted by Pamela Seley, Residential Real Estate Agent serving SW RivCo CA (West Coast Realty Division) almost 5 years ago

Fortunately we have little Radon gas problems in Oklahoma. However we do have problems with metal in slab ducting that gets rusted and needs to be run overhead. Now virtually all of our builders run overhead systems so starting in the 1990's this has been pretty standard for most homes. Your post does make me wonder if this was missed when they bought the home or had they owned it for some time and the problem developed slowly and without notice.

Posted by Joe Pryor, REALTOR® - Oklahoma Investment Properties (The Virtual Real Estate Team) almost 5 years ago

I ran into the same problem, with a home that had no basement, but ductwork under the slab.

Posted by Alan May, Helping you find your way home. (Coldwell Banker Residential) almost 5 years ago

I have only seen PEX a couple of times in my career here Andrew.  But radiant floor heating, outside of being hugely expensive, solves on the heat side of the HVAC equation.

Pamela - inspections are essential!  And they should look at the entirety of the house.

These are the original owners Joe!  Everything was hunky dory when they bought the house.  And no one did radon testing.

Did they remediate the radon Alan?

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Never have seen a home with duct work in the slab. That has to be a pain.

Posted by Bill Reddington, Destin Florida Real Estate (Re/max Southern Realty) almost 5 years ago

I am with Bill, above. I didn't know ducts could go in a slab. That doesn't make any sense to put something where you basically can't get to it. That's going to be a hard sell. Thanks for sharing.

Posted by Jill Winchel, We make it easy. You make it home. (Royal Shell Real Estate - Koffman & Associates ) almost 5 years ago

They have been doing it for decades, although in the past couple of decades they have gotten away from it Bill.  It is not a good idea.

Jill - I was just in your neighborhood over the weekend for a wedding!  It might be a hard sell, to be sure.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

I have worked for a construction firm when I was younger and I can say that this is one tough issue and not everybody in the field of repairs and renovation can do a great job on it. I am glad that you were able to find out about this and I hope this gets resolved at the soonest and cheapest way.

Posted by Michael Ha Elmhurst, Woodside, Maspeth (Rego Park, Forest Hills, Jackson Heights, Corona, Middle Village) almost 5 years ago

Michael - my clients checked around and no contractor the called would touch this, including the radon guys.  So they went to find another house.  I doubt I will find out how this ends for the seller.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Yes... they had to remediate... at a cost of about $1,200.00  (this was a few years ago).... we were all surprised at the higher than allowable result in a house without a basement ... but then the radon remediation guys explained basically what you outlined in this post.

Posted by Alan May, Helping you find your way home. (Coldwell Banker Residential) almost 5 years ago

I've ran into some leaking plumbing pipes under slabs ( Sterling or Herndon area) which could be fixed with help of a diamond tip concrete saw, etc, but this duct and radon problem are two serious issues. Without seeing it, I could only guess at ideas. At first I was thinking something along the lines of how a chimney flu is lined, pull a smaller duct through the existing ducts, but size could be a problem. Or consider raising the floor, or cutting channels in existing floors for new ducts, then fill in old ducts. All just guesses. Sellers might not have money for that, so maybe they can lower price?

Posted by Jeff Pearl, Full Service Full Time Realtor (RE/MAX Distinctive / LIC in VA) almost 5 years ago

Ductwork under a slab??? Who does that??? I have never seen that in California. The only solution fo the seller is to fill those ducts with concrete and install wall furnaces and an evaporative cooler or go with an industrial/warehouse look with exposed ductwork hanging from the ceiling. Your clients did the right thing by moving on.

Posted by Matthew Sturkie, CRS, GRI 909-969-3805, CRS, GRI 909-969-3805 (Action Realty) almost 5 years ago

That is certainly a costly and involved issue. Poor sellers is right.

Posted by Suzanne Otto, Your Montgomery County PA home stager (Six Twenty Designs) almost 5 years ago

Not insurmountable but it's going to be tricky that's for sure. Possibly adding another entire system plus the remediation.

Posted by Lyn Sims, Schaumburg IL Real Estate (RE/MAX Suburban) almost 5 years ago

That does not seem expensive Alan.  This house has two slabs, one 2' lower than the other.  The radon guy said no way would he try!

Jeff - the ducts are 5" wide now, smaller than a modern HVAC system would want to blow air through.  I don't know what they could be lined with either since they vary in length and depth, even one to another.  The buyers walked on all that, and other things.

Matthew - I had to look up "evaporative cooler."  Don't know what that is!  We don't have them here.  Too humid to work apparently.  I am going to doubt the seller would want to put in a new panel box to accommodate a new electric heating system!

Suzanne - I feel bad for them.  They have a tough issue to sell now.

That would be the only solution Lyn.  But nobody seems to know what kind of new system to install or how it could be done, and the radon companies don't want to try this one!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Jay, I've never heard of this before. Homes on a slab here have ductwork in the attic. It sounds like an expensive proposition to solve. I feel for this seller. He may never be able to sell his house.

Posted by Tammie White, Broker, Franklin TN Homes for Sale (Franklin Homes Realty LLC) almost 5 years ago

Tammie - they don't do it any more here.  In those days it was considered state of the art!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Jay, I did not realize radon was an issue in Virginia.  Here in Colorado we have a lot of decomposed granite (crumbled mountains) that the foundations of houses sit on.  Radon has become an issue here for that reason.

Posted by Kelly Young, Colorado Springs Real Estate ~ 719-226-0126 (The Platinum Group Realtors) almost 5 years ago

Wow.  Really interesting stuff.  I wonder if it is a good thing having a home on slab or a raised foundation?

Posted by Jay & Michelle Lieberman, Creating Calm in the Buying and Selling Chaos (Keller Williams World Class) almost 5 years ago

Jay, Luckily this is not a common practice out here. I have only seen a few home done this way and I thought the duct were the least of the problems ;)

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) almost 5 years ago

This is an interesting post.  I am lucky not to have run into anything like this.  It look like this is a very complex issue and one that may be difficult to resolve.

Posted by Joan Whitebook, Consumer Focused Real Estate Services (BHG The Masiello Group) almost 5 years ago
Basements are pretty common here, but so are slabs. Haven't ever run into this problem and hope I don't have too.
Posted by Evelyn Johnston, The People You Know, Like and Trust! (Friends & Neighbors Real Estate) almost 5 years ago

Kelly - if you look at radon maps you will see that most everywhere there is a lot of rock, granite and shale, there is radon as uranium is contained in the rock.  Virginia has LOTS of rocks, and mountains.

J&M - either is good, so long as the ducts aren't buried!

It isn't the practice here any longer Don, but there are many houses here with buried ducts like this.

Joan - and given that my clients decided to find another place.

Evelyn - those are the only alternatives!  And both come with their own particular problems!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

It's a pity but you have to call them like you see them.  I do feel for the sellers sounds like the only remedy left is to tear the place down and start all over. 

Posted by James Dray, Exceptional Agents, Outstanding Results (Fathom Realty AR LLC) almost 5 years ago

Or live with the radon James, which, in my opinion, is not that serious a problem.  In the meantime the ducts will not get any better however!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Jay - I'm with some of the other posts in that I never knew that ducts could/would be installed under the slab.  It's great for the buyers that you helped see the pitfalls of the property, but I see a very expensive fix ahead for the sellers.

Posted by AJ Heidmann ~ CRS, YOUR Alexandria & Arlington, VA Real Estate Expert (McEnearney Associates, Inc.) almost 5 years ago

Or no fix at all AJ.  It could be that another inspection does not turn up all of the components of the problem as they relate to everything else.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

I've never heard of or seen ductwork in a slab. I guess the cathedral ceilings were the cause of running ducting like that, but just seems like it was a very short-sighted solution. Sounds like if they really wanted a house built like that it should have been built on a crawl space or basement instead.

Posted by Aaron Hofmann, aka Mr. Smyrna Vinings (Atlanta Communities) almost 5 years ago

That was not uncommon in the 60s and 70s Aaron, at least around here.  Over time it has proven to be a huge problem.  Where this house is located, none is on a basement.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Jay, I sold a house several years ago that had a radon problem. It was an easy fix to mitigate the problem. This one is not an easy fix.

Posted by Michael Setunsky, Your Commercial Real Estate Link to Northern VA almost 5 years ago

I get high radon results from time to time Michael, but in most homes it is an easy fix.  This one is not!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

While there are certainly some excellent features and benefits fro a buying a much older home (location, style, character etc) you have to consider exactly what you mention the house is built to work a certain way and to change that only opens up doors for possible major issues

Great post

Posted by David Shamansky, Creative, Aggressive & 560 FICO - OK, Colorado Mtg (US Mortgages - David Shamansky) almost 5 years ago

Wow, thank goodness most builders don't put duct work in the slab. It would also be a maintance nightmare.  Yet some building techniques do change over the years so I am sure something that is considered great today, may also have its limitations in the future. Thanks for the reminder.

Posted by Stephen Turner, The BIG Guy of NEW HOME SALES (TriCorner Homes (TriCorner Realty)) almost 5 years ago

David - thanks!  New techniques sometimes don't work in older structures, as in this case.

Steve - live and learn.  We always are trying to improve, but sometimes the old doesn't match what the new has to offer.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

Jay - The sellers are really between a rock and a hard place as the saying goes. This conditions that was found shows the value of a home inspection.

Posted by Eric Middleton, Professional Property Inspector (Closer Look Property Inspections Inc.) almost 5 years ago

This is a big deal, in my opinion Eric.  I hope they can resolve this, but my clients are looking elsewhere.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 5 years ago

This blog does not allow anonymous comments