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Old 04-14-2012, 09:16 PM   #16
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Odor from Crawl Space


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Originally Posted by WillK View Post
Okay I'm confused. On one hand you say that a company made your crawlspace conditioned and sealed. But you also describe vents. These are two mutually exclusive terms - the crawlspace is either sealed or vented.

Read this http://www.buildingscience.com/docum...nd-crawlspaces

Is there or was there any insulation in the floor joists over the crawlspace?
Thanks for the reply. The crawl is conditioned and sealed. The vents I speak of are floor vents or the damper vents placed on the main trunk line of the HVAC. Hope that clears it up. There was insulation under the floor before the mold was treated. It is completely gone now. The only insulation in the crawl is called EcoBatt and it is stuffed above the outer walls above the Thermax.

Of note to all: I had a third party come in today to check everything out. Unfortunately he was not able to pinpoint anything that I haven't considered. He did say that the HVAC returns inside the house smell strong like the crawl. BUT...my installer has removed some of the duct lines and checked them and didn't notice a bad smell. Going in circles!!!

Thanks to all.

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Old 04-14-2012, 10:58 PM   #17
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Odor from Crawl Space


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Originally Posted by G Ollis View Post
Thanks for the reply. The crawl is conditioned and sealed. The vents I speak of are floor vents or the damper vents placed on the main trunk line of the HVAC. Hope that clears it up. There was insulation under the floor before the mold was treated. It is completely gone now. The only insulation in the crawl is called EcoBatt and it is stuffed above the outer walls above the Thermax.

Of note to all: I had a third party come in today to check everything out. Unfortunately he was not able to pinpoint anything that I haven't considered. He did say that the HVAC returns inside the house smell strong like the crawl. BUT...my installer has removed some of the duct lines and checked them and didn't notice a bad smell. Going in circles!!!

Thanks to all.
G,

How many HVAC returns (as defined by the third party) are there inside your house?
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Old 04-15-2012, 01:37 PM   #18
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Odor from Crawl Space


John,

There are two returns inside my house. My house is approximately 2200 sq ft. One thing I did not mention earlier is that I have a sunroom off the back of the house that was added on before we bought the house. The sunroom is heated and cooled by the same HVAC system. The sunroom does NOT smell. I also had the front porch, which is covered brick, checked. There is no smell under the front porch. I say all of this because it makes me think more and more that the smell was caused by something placed in the crawl during sealing, I just don't know what that is.

G
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Old 04-15-2012, 05:47 PM   #19
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Odor from Crawl Space


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John,

There are two returns inside my house. My house is approximately 2200 sq ft. One thing I did not mention earlier is that I have a sunroom off the back of the house that was added on before we bought the house. The sunroom is heated and cooled by the same HVAC system. The sunroom does NOT smell. I also had the front porch, which is covered brick, checked. There is no smell under the front porch. I say all of this because it makes me think more and more that the smell was caused by something placed in the crawl during sealing, I just don't know what that is.

G
G,

It seems that way to me too.

They put something into, or did something to, your crawl space that is creating the bad smell.

But its confusing that the smell is not reaching the sun room.

That makes it seem like the smell is coming up through the floor of the main house everywhere, not just up from the supply registers in the floor of each room.

Is the smell worse in some room than in others? Maybe bathrooms, kitchen. laundry room - places where plumbing comes up through the floor.

Is the bad smell stronger at the supply registers in the floor (in your main house rooms) than it is elsewhere in those rooms? Is it more noticeable at those supply registers when air is moving through the HVAC system?

If you turn the HVAC completely off, including no circulation mode, so that no air is moving through the HAVC system - then open the windows until the air smells good - then close the windows - then, still keeping the HVAC off - how long does it take for the smell to come back inside the house? Does it come back quicker if you turn the blower, heat or cool on right after closing the windows?

Last edited by John_W; 04-15-2012 at 06:16 PM. Reason: added extra question
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Old 04-15-2012, 09:05 PM   #20
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Odor from Crawl Space


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G,

It seems that way to me too.

They put something into, or did something to, your crawl space that is creating the bad smell.

But its confusing that the smell is not reaching the sun room.

That makes it seem like the smell is coming up through the floor of the main house everywhere, not just up from the supply registers in the floor of each room.

Is the smell worse in some room than in others? Maybe bathrooms, kitchen. laundry room - places where plumbing comes up through the floor.

Is the bad smell stronger at the supply registers in the floor (in your main house rooms) than it is elsewhere in those rooms? Is it more noticeable at those supply registers when air is moving through the HVAC system?

If you turn the HVAC completely off, including no circulation mode, so that no air is moving through the HAVC system - then open the windows until the air smells good - then close the windows - then, still keeping the HVAC off - how long does it take for the smell to come back inside the house? Does it come back quicker if you turn the blower, heat or cool on right after closing the windows?
John,

It appears to me that the smell does come from the floor vents and registers ONLY because that is where more air leaks are found in general. However (The heat has been off two days. The smell was semi-strong.) we turned on the air conditioning today to give it a try. The smell was worse after 3 hours (we had left to go shopping). We actually noticed it a bit more in the sunroom tonight. My wife says it seems worse in my son's room which is one one side of the house and our bathroom which is on the other side of the house. I personally think this is because we do not open windows or have a window in those rooms. My father-in-law is a contractor and called a friend that has been preaching sealed crawl space for 30 years. Just telling him the story, he seems to think the floor joist may still be damp from the chemicals used to kill the mold. Normal moisture testers show they are dry. Also, another friend said there house smelled somewhat like ours and it turned out to be the glue used to fasten the air ducts to the boots of the floor vents. Do you think the sealed crawl could cause the glue in out house to become smelly?

My installer is at his wits end as well. We are going to start removing stuff beginning tomorrow with the Ecobatt insulation. We shall see what happens.

I also want to add that the smell in the house is slightly less in strength than the smell in the crawlspace if you go under the house. Thanks for everything to everyone that has a suggestion.

G
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Old 04-15-2012, 11:14 PM   #21
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Odor from Crawl Space


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Originally Posted by G Ollis View Post
John,

It appears to me that the smell does come from the floor vents and registers ONLY because that is where more air leaks are found in general. However (The heat has been off two days. The smell was semi-strong.) we turned on the air conditioning today to give it a try. The smell was worse after 3 hours (we had left to go shopping). We actually noticed it a bit more in the sunroom tonight. My wife says it seems worse in my son's room which is one one side of the house and our bathroom which is on the other side of the house. I personally think this is because we do not open windows or have a window in those rooms. My father-in-law is a contractor and called a friend that has been preaching sealed crawl space for 30 years. Just telling him the story, he seems to think the floor joist may still be damp from the chemicals used to kill the mold. Normal moisture testers show they are dry. Also, another friend said there house smelled somewhat like ours and it turned out to be the glue used to fasten the air ducts to the boots of the floor vents. Do you think the sealed crawl could cause the glue in out house to become smelly?

My installer is at his wits end as well. We are going to start removing stuff beginning tomorrow with the Ecobatt insulation. We shall see what happens.

I also want to add that the smell in the house is slightly less in strength than the smell in the crawlspace if you go under the house. Thanks for everything to everyone that has a suggestion.

G
G,

Your tests and observations say the smell is being introduced into the living space, including the sun room, by the HVAC system. More specifically, the smell is getting sucked into the return side of the system from within the crawl space and pushed out into the supply trunk and then out and up through the floor vents.

I suppose anything is possible. I doubt that sealing the crawl space would have any effect on adhesive sealants. But I only have my own house as an example.

In our ducting, the runs from the supply trunk to the boots in the floor are flex. They are strapped to, and also taped to, the narrow, round bottom end of the boots with aluminum tape designed for HVAC use. The wide, rectangular tops of the boots are nailed sideways into the floor - and the gaps between the top of the boots and the surrounding floor opening are sealed with an adhesive sealant (polyurethane?). The radon mitigation barrier in our crawl was sealed/glued to the block walls with a very potent smelling (very dangerous to breathe) bonding agent (butyl rubber), applied with a caulk gun.

Once they cured, both adhesive sealants seem very durable and stable. They are still a little flexible but very tough. The smell from the dangerous stuff wore off in just a few days, if that long, and never came into the living area. I never smelled much of anything from the boot-to-floor adhesive. (I am very sensitive to chemical and other smells.)

If whatever they put into your crawl could affect good, cured adhesive sealant like what we have, especially over such a long time frame, it would seem to me to be a danger that needs to be removed.

Still, your house, and particularly your duct work at the boots, might have sealing 'technology' that I've never seen. If you can access some of that sealing material when you are in the crawl, maybe you can scrape some samples off and check it.

Again though, since the smell is everywhere down there, the source of the smell is probably everywhere too. To me, it seems likely that the source is widespread and fundamental to the work/materials used in the sealing process. My bet is that some chemical, material or combination of those that went into the overall process of sealing your crawl is producing that smell - maybe, in part, by interacting with the preexisting materials in the crawl - but all over/around the crawl, not just in isolated spots like the boots.

You are lucky to have such a concerned installer. There are contractors that would just say "see you later" because otherwise, by spending more time on trying to resolve the problem, they will lose money on the project.

Let us know how things develop.

Last edited by John_W; 04-16-2012 at 03:38 AM. Reason: improve thoughts
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Old 04-17-2012, 01:59 PM   #22
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Odor from Crawl Space


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Originally Posted by G Ollis View Post
Thanks in advance for anyone who can help!

We also had a conditioned, sealed crawl space installed. The installer used a 20 mil vapor barrier and Thermax(TM) board insulation for the walls of the crawlspace. There are vents and returns along the main trunk line as required by code.

Gary
Gary,

Rereading your initial post, it finally sunk in that your HVAC ducting may have been modified to make your crawl space part of the conditioned space of your house. Sorry for being so slow on the uptake.

If the crawl and indoor air are freely mixing, by design, then the only way to get the indoor air to smell nice will be to find and fix the source of the smell down in the crawl.

In my case there is a bad smell in the crawl space that has, so far, resisted all attempts at eradication. But, I do have a "solution" of sorts as I am able to soak up that smell before it can be sucked into the HVAC system.

With a conditioned crawl, my "solution" won't work for you. But, you can keep it in your back pocket, as a last resort (revert back to separate crawl and indoor air).

Hope you are having luck finding and fixing the smell.


P.S.

Could the smell just be what the walls, floor and joists down there have absorbed from the crawl since the house was built? I know that even the space inside interior walls can smell bad. It seems like making the crawl ready to be part of the conditioned space should include covering up such surfaces with something like a really good stain/odor blocking primer.

Last edited by John_W; 04-17-2012 at 04:33 PM. Reason: extra thought
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Old 04-17-2012, 08:07 PM   #23
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Odor from Crawl Space


I hope I don't jinx myself but...

The installer removed the EcoBatt insulation in the crawl on Monday afternoon. He placed a fan in front of a crawl space door to remove particles in the air due to the insulation removal. I went to the house today (we have been staying with my in-laws for a week now) and it was much much better. I had my wife run the fan on the HVAC system for 3 hours until I could go by to check it. At 5:30 today, the house did not smell hardly at all. Now I realize it could just be the fresh air in the crawl space with fan, BUT I went into the crawl and smelled in front of the fan and the smell is maybe 25% of what it has been. We HOPE the insulation adsorbed the remediation smell, off gassing, chemical, etc. and that is what the smell was. We are going to let it air out for a few days.

The ultimate test will be when the crawl door is closed with no fan. I will keep you posted.

G
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Old 04-19-2012, 07:28 PM   #24
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Odor from Crawl Space


Update...

The removal of the insulation "helped" with the overall smell BUT it is not the source of the odor. After three days without the insulation and a fan pulling air from the crawl, the smell remains in the crawl but not as strong. I attribute the not as strong simply to the fan being on 24 hours a day for the last three days. This weekend we are going to do an ozone shock to the crawl space and check it again on Monday.

FYI...the third party that checked my house two weekends ago is a friend of mine. He called me the other day and informed me that he was in a meeting with several colleagues and the general thought of those in attendance (who are remediation contractors and sealed crawl) is the vapor barrier is causing the smell due to a reaction with the soil under the house. They have found that the vapor barrier produces a smell in some crawls and not in others. Their opinion is that it has to do with the soil. If the ozone doesn't work, the v.b. is getting replaced.

I shall keep digging until I get to the bottom of this situation.

G
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Old 04-20-2012, 11:40 AM   #25
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Odor from Crawl Space


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Originally Posted by G Ollis View Post
Update...

The removal of the insulation "helped" with the overall smell BUT it is not the source of the odor. After three days without the insulation and a fan pulling air from the crawl, the smell remains in the crawl but not as strong. I attribute the not as strong simply to the fan being on 24 hours a day for the last three days. This weekend we are going to do an ozone shock to the crawl space and check it again on Monday.

FYI...the third party that checked my house two weekends ago is a friend of mine. He called me the other day and informed me that he was in a meeting with several colleagues and the general thought of those in attendance (who are remediation contractors and sealed crawl) is the vapor barrier is causing the smell due to a reaction with the soil under the house. They have found that the vapor barrier produces a smell in some crawls and not in others. Their opinion is that it has to do with the soil. If the ozone doesn't work, the v.b. is getting replaced.

I shall keep digging until I get to the bottom of this situation.

G
Good luck.
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Old 04-21-2012, 10:30 AM   #26
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Odor from Crawl Space


I have been in a few sealed crawls and have one in my house as well that was installed along with a geo thermal system. All the sealed crawls I've been in smell like cat pee and if there was a smell issue in the house the smell penetrated the living space by seeping through cracks in the flooring and walls where they sit on the sub floor. This especially in older homes that were not built up to the insulating standards now practiced in building. Also the smell will enter the house through incorrectly installed/sealed ductwork under the house.

Because of pressure every time the heat or air cuts on in the house it pulls minute amounts of under the house air up through small holes as mentioned above and this air then gets circulated throughout the house via air return system.

A fresh air box added to the ac/heat system will most likely help to mix accumulated - inside the house smelly air - with fresh air and make it not quite as noticable and also provide fresh oxygen into an otherwise sealed enclosed air system.

On my house the cat pee smell has lessened considerably over time ( sealed crawl installed Oct 2010 ) and is now not noticed in the house but can still be smelled underneath inside the crawlspace...

Last edited by hand drive; 04-21-2012 at 10:34 AM.
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Old 04-28-2012, 08:53 PM   #27
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Odor from Crawl Space


Thanks for the responses.

Here is an update...

Officially, we still do not know what is causing the odor. Unofficially, and what I believe to this point, I have been told that the mold after being treated and killed goes through a dying cycle. Evidently the mold gives off a gas as it dies and can take an undocumented amount of time to quit gassing. I have spoken to consulting firms, non-profit companies, etc. and the universal answer is to air seal all the leaks from the crawl to the living area and vent the crawl. That is what I have done to this point. The smell is much better in house and I think if we can get a good patch of warm weather I will be able to open up all my windows and air out the inside. I have not had a chance to do this yet after the air sealing. At least the house is livable now.
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Old 04-28-2012, 11:10 PM   #28
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Odor from Crawl Space


Sounds to me that it's probably the soil, and you need a better, or at least a different, vapor barrier on the floor. However, you could consider trying to fog the crawl with Concrobium. Buy a gallon and rent the fogger (both available at Home Depot), might cost a total of $50 and take a couple hours time max. The stuff is non-toxic to people/pets. I know your air tests say less than average mold currently, but any mold spores that may have been disturbed during remediation could have settled down and could smell bad now that you're sealed up. If it helps, you can assume the primer/sealer job may be worth doing (but you may not have to as Concrobium encapsulates the mold). If it doesn't help, at least you know there's no need to go through the added expense and labor of priming everything down there.
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Old 05-01-2012, 05:57 PM   #29
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Odor from Crawl Space


Interesting thread... I'm in the process of working up to sealing my crawlspace. One of the things I'm planning to do is vent the crawlspace to outside with bathroom fans. My intent is to end up sealed, but I have visible mold on my dirt and any time the crawl access is open dust gets into the living space. I was going to put in drainage, but I have a sump pit and no longer have flooding so at this point I'm guessing that the vapor barrier might do me more good sooner than later.
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Old 05-01-2012, 06:38 PM   #30
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Odor from Crawl Space


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Interesting thread... I'm in the process of working up to sealing my crawlspace. One of the things I'm planning to do is vent the crawlspace to outside with bathroom fans. My intent is to end up sealed, but I have visible mold on my dirt and any time the crawl access is open dust gets into the living space. I was going to put in drainage, but I have a sump pit and no longer have flooding so at this point I'm guessing that the vapor barrier might do me more good sooner than later.
I think you may find you really need a concrete floor to make a sealed crawl. Basically, a sealed crawl is like a really short basement. An earthen-bottom crawl is difficult to seal up...

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