Hello all,
Own a duplex in central Indiana and live in one half. The neighborhood of rentals seems to built on clay and silty soil, though I have not had a soil analysis. When it rains water stands for days afterwards. The HVAC supply duct in my kitchen has no flow because the water is blocking the entire pipe. I’ve been in denial about because of the solutions.
1. Jackhammer out the slab and fix the supply duct.
2. Install french drains around the perimeter to drain away from the house.
My question is how effective would a perimeter drain only be because I’m trying to avoid the concrete dust and gaping muck hole in my kitchen. I tried to file a home insurance claim and they said they wouldn’t cover it unless it was a problem in many houses. I know both my neighbors have also had water in their ducts but have had no cooperation from other landlords. I’m concerned about mold, legionella and liability. What suggestions do you have? Thanks in advance.
John
Replies
OK John. Your Pitot tube is blocked and your ASI is broken. Do you A. clean the Pitot, B. fix the ASI or maybe...C. Both of the above?
DG/Builder
1. Call maintenance!
2. That feels like about 200knots!
3. Cancel the trip and get a day off!
The military has flamethrowers. And what this indicates to me, it means that at some point, some person said to himself, "Gee, I sure would like to set those people on fire over there. But I'm way to far away to get the job done. If only I had something that would throw flame on them."
George Carlin
Are all the first floor ducts under he slab or just a few? Is it a 2 story building or a one? How old are the HVAC units?
Matt,
One story Slab on grade. All Supply ducts are under the slab. Returns are above the ceiling. Forced air furnace and A/C. House was built in 1997. The Supply ducts look like 8" corrugated flex duct and the kitchen duct takes a dive downwards where the water is.
John
The military has flamethrowers. And what this indicates to me, it means that at some point, some person said to himself, "Gee, I sure would like to set those people on fire over there. But I'm way to far away to get the job done. If only I had something that would throw flame on them."
George Carlin
Edited 1/30/2006 9:15 am ET by Jcpilot
If you have any ground water in your slab underfloor ductwork your fears of mold and illness are very real. If your kitchen supply is getting blocked completely you probably have some water in your other ducts too.
The only safe solutions are to get the ground water away from the house before it can enter the ductwork. How's the grade around the foundation? Sloping away all the way around the house?
My preference would be to redo the ducts to deliver your conditioned air through a small duct high velocity system. If your home is a single story this retrofit can be done fairly easily through your attic with small diameter insulated ducts. This is also a great way to retrofit an older home that doesn't have A/C.
Rich,
I have seen water in one other duct when I first moved in. I had taken a wet dry shop vac and sucked out as much water as I could and had airflow from the kitchen duct for a short time. Grading around the house is away from the foundation but my side property lines are 8 feet from the building line and my neighbors grading slopes to that spot as well. The water pools at the that low spot for days after a rain. I guess I could try the perimeter drain and see what happens then take it from there. I hadn't thought of a retrofit but the I didn't care for the high velocity systems for the noise. I'd love to put radiant heat in the house I'm going to build. I wonder if a concrete loborer steped on a duct while pouring the slab. Should the ducts be water tight?
I have noticed a trend among builders around here that seems questionable and I think applies to my house. I have seen the tops of footers poured level with grade. Two courses of block and dirt graded have way up the lower course of block and the slab poured. I haven't dug down to see what's there in my case. Would a shallow footer help or hurt me with trying to keep water out from under the slab when using a perimiter drain in expansive soil. Thanks for the quick responses.
JohnThe military has flamethrowers. And what this indicates to me, it means that at some point, some person said to himself, "Gee, I sure would like to set those people on fire over there. But I'm way to far away to get the job done. If only I had something that would throw flame on them."
George Carlin
The duct in question.
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Duct is on the other side of the large window. There is a four foot sidewalk covered by roof before the duct!
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Landscaping in front of house doesn't slope away until driveway.
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North elevation.
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Grading West elevation looking South.
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Looky here at my neighbors house!!!
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South Elevation looking East.
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Standing Water South elevation.
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East elevation looking North.
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I know what I have to do and I think this post is a kick in the a$$ to grab a shovel and dig around my house when it warms up. If anyone see's something I haven't mentioned please let me know.
JohnUseless things in aviation. 1. Altitude above you. 2 Runway behind you. 3 Fuel in the fuel truck.
http://mysite.verizon.net/respum0e/johnclanton/
If you can do a perimeter drain, you can just as easily fix the standing water. Tile the standing water area to daylight.
If ignorance is bliss why aren't more people
happy?
Hi John,
Like Dan H. said, the best and most cost effective method would be to fix the grade. I would also make sure you get rid of any standing water in the area. It may be as simple as that. Any areas you can add even just a few inches around the foundation can make a difference.
I don't see much slab construction in my area but when it's done they add rock and sand under the floor to insure adequate drainage and avoid water problems. And no, HVAC duct is not water tight. It can be sealed, but it's not water proof.
You mentioned radiant for your new house. It can be pricey but it's worth every penny! Even the most inexpensive system with the simplest controls is going to be infinitely more comfortable than a forced air system. I've never had a customer say they wish they wouldn't have spent the money for radiant, but I've heard plenty say after the fact that they should have! Also the high velocity systems installed correctly are no more noisy than a standard forced air system. I'v used them in some very nice homes for A/C when doing radiant installs and not had any noise complaints. I'm getting ready to do the same in mine when I build this summer.
Hope this helps, Rich
I would find a way to run the duct above grade and then fill the old duct with concrete.. 2+3=7
A properly done perimeter drain should work. Think about how the water is getting from the sky to the duct ... it falls on the ground and leaks under the slab. Prevent it from getting under the slab and the duct should stay dry.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Fix the drainage outside the house so water doesn't stand there.
Also, there should be a drain to a dry well or some such in the under-slab duct. Try to figure out where it would be and see if you can run it to daylight.
happy?
There is a waterproof duct material used in this area under slabs--SpunStrand--but it's very expensive and you'd have to cut access thru the floor to install it. I'd follow the others advice about trying to drain the water from the exterior. Unfortunately the channels they cut thru the clay to install the ductwork are functioning as underground rivers now, and filling up your ductwork. Drainage work may stop the water from collecting to the point where it blocks the pipe, but it may not stop the pipe from eventually rusting out.
I am kinda of surprised that you have enough water to completely block air flow. I suspect that you are right that the ducts where either crushed or might have big dips in them.
And from the pictures I see that while you have some slope the area is fairly flat. And you mentioned several neighbors have problems. So the water table might be too high to easily fix the problem.
But the first step is definetly regrade and/or put in surface drains to get the water out before it can soak in.
If that does not solve the problem then you can dig a couple of test holes and see how much water that they have in them and how quickly that the refill after you pump them out. That will help determine if a footing drains around the outside of the house will work or if the water level is just too high.
I had a similar problem. My house is on a hill side with the garage and basement under the garage 1/2 flight higher than the house. The 1st flr of the house is slab with ducts under it.
About 4 times in the first 10 years when we would have a week of wet weather followed by a hard rain the ducts would get about 1/3 full of water. And it was like a sunna and wave pool with the furnace air setting up tidelwaves in the duct. About 24-36 hours later the water would be gone.
Started digging up in one corner to see about putting in drainage and found a small spring, but that was not the real problem. There was a footing drain from the higher level that just ened right at the slab level of the lower level. Extended that out to daylight and have not had a problem since.
Tain't all that hard. He says that the duct dives down near the problem register for some reason, so water will collect there.First time we had water in our ducts the wife noticed it because of the blub-blub sound she heard when the furnace came on.
If ignorance is bliss why aren't more people
happy?