Author Topic: Crawlspace Makes My House Smell  (Read 2930 times)

El_Viajero

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Crawlspace Makes My House Smell
« on: June 16, 2017, 07:58:30 PM »
I'm in a fix with this one. My crawlspace is making my house stink, but here's the thing: It only happens on rainy days.

The smell in my house on rainy days is the same as the smell inside my crawlspace all of the time. If it's not raining, I don't smell it in my house. If it does rain even just a little bit I smell it in a big way.

Some facts about my crawlspace and my house:

1. HVAC is down there
2. It's partially encapsulated, not fully
3. I've got a vapor barrier all along the floor and nailed to the concrete walls about 6" above the ground.
4. The vapor barrier also extends up the piers about 6".
5. I've closed off all the vents.
6. I've got a dehumidifier down there and keep it at 60% RH
7. It's got relatively modest amounts of mold on the joists nothing crazy. Just some fuzzy stuff. No more is growing b/c I've had the dehumidifier running down there for over a year. I've not cleaned the mold.
8. I've sealed my ducts with mastic and mastic tape all over the place; I've even sealed the air handler cabinet.
9. I've sealed all the floor penetrations (HVAC, plumbing, electrical) with fire caulk.
10. I have a whole-house dehumidifier that keeps the inside of my home at 50% RH or less.
11. The dehumidifier has a ventilation damper that brings fresh air into my home, filtered and dehumidified, for 15 minutes out of every hour.

So I've got this fancy ass crawlspace and fancy ass dehumidification/ventilation system and I still have an indoor air quality problem. It's been at 60% RH or less down there for over a year. I have no idea what to do, but...

1. I've read reports about people smelling soil gas (not radon, but other gases) following crawlspace encapsulation. After installing the type of mitigation system normally used for radon, the smell went away.
2. There is a particular type of vapor barrier that has, in some homes, given off a bad smell. I might have that type of vapor barrier, but I don't understand why I'd smell it considering I've sealed off my ducts and sealed the floor penetrations in the crawl space.

And the fact that I only smell it when it rains is just... weird. Any ideas? If it's soil gases, I'm wondering if I should seal the vapor barrier to the walls of the crawlspace before installing a radon mitigation system. Is that the next step? I'm at a loss.

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #1 on: June 17, 2017, 06:36:13 AM »
Couple of thoughts here. I have build a couple of dozen new homes on sealed, conditioned crawl spaces, and for the most part,  they have been incredibly successful.  First, I always instructed clients to monitor crawl space humidity and temperature, and to address it when the temp drops below 50* or the RH exceeds 50%.  I provide a remote read thermometer/humidity gauge with the display located in the kitchen or other area where it's going to be seen, and the remote hung off the floor joists in the crawl.  IMHO, this should be your very first step. If you have visible mold on the floor joists your RH is WAY too high, and you are relying on the dehumidifier readout to tell you what the level is, which may be wildly inaccurate.  Next, I'm really not understanding why you smell anything in the home at all?  I always used closed cell spray foam on the interior of my crawl walls. Codes dictated that this be coated with a fireproof spray on coating. This "paint" offgasses a horrible Ammonia smell for a very long time. The only way I ever smell it is when I enter the crawl, it is NEVER noted in the home. My guess is that you have a pretty serious air leakage issue from the crawl into the home, which is undesirable for a few reasons, including energy efficiency and radon incursion.Finally, if you monitor the RH in the craw you will note that it will increase as the ground is saturated with  rain. I commonly saw spikes in RH after a few days of rain.

Based on everything you provided, my theory is that you are not getting the RH down to acceptable levels by setting the dehumidifier at 60%, it needs to be less that 50%.  Dehumidifiers have a very high failure rate, and commonly fail in a few years of service. I have had customers who listened to the thing run and cycle and couldn't understand why the RH was spiking. You need to see a regular output of drain water to confirm that it is working properly, as they will run, cycle and sound fine, without removing a drop of moisture from the air.  The other issue is, you shouldn't be able to smell anything from the crawl, while in the home. I would guess that there is significant air leakage in the house, and a significant "Chimney effect" drawing air from the crawl, through the occupied space, and up into the attic. This isn't hard or expensive to address, but there are huge benefits to air sealing the floor above the crawl and the "floor" of the attic space.

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #2 on: June 19, 2017, 07:08:58 AM »
Couple of thoughts here. I have build a couple of dozen new homes on sealed, conditioned crawl spaces, and for the most part,  they have been incredibly successful.  First, I always instructed clients to monitor crawl space humidity and temperature, and to address it when the temp drops below 50* or the RH exceeds 50%.  I provide a remote read thermometer/humidity gauge with the display located in the kitchen or other area where it's going to be seen, and the remote hung off the floor joists in the crawl.  IMHO, this should be your very first step. If you have visible mold on the floor joists your RH is WAY too high, and you are relying on the dehumidifier readout to tell you what the level is, which may be wildly inaccurate.  Next, I'm really not understanding why you smell anything in the home at all?  I always used closed cell spray foam on the interior of my crawl walls. Codes dictated that this be coated with a fireproof spray on coating. This "paint" offgasses a horrible Ammonia smell for a very long time. The only way I ever smell it is when I enter the crawl, it is NEVER noted in the home. My guess is that you have a pretty serious air leakage issue from the crawl into the home, which is undesirable for a few reasons, including energy efficiency and radon incursion.Finally, if you monitor the RH in the craw you will note that it will increase as the ground is saturated with  rain. I commonly saw spikes in RH after a few days of rain.

Based on everything you provided, my theory is that you are not getting the RH down to acceptable levels by setting the dehumidifier at 60%, it needs to be less that 50%.  Dehumidifiers have a very high failure rate, and commonly fail in a few years of service. I have had customers who listened to the thing run and cycle and couldn't understand why the RH was spiking. You need to see a regular output of drain water to confirm that it is working properly, as they will run, cycle and sound fine, without removing a drop of moisture from the air.  The other issue is, you shouldn't be able to smell anything from the crawl, while in the home. I would guess that there is significant air leakage in the house, and a significant "Chimney effect" drawing air from the crawl, through the occupied space, and up into the attic. This isn't hard or expensive to address, but there are huge benefits to air sealing the floor above the crawl and the "floor" of the attic space.

Thanks for the input! With regard to the visible mold on the floor joists: Won't this just stay there unless I clean it? If I drop it to 50% RH down there, will the mold, I don't know... dry up and disappear from the floor joists? In the wintertime, it gets down to 30% RH down there for months at a time, and that hasn't made the mold wither and die.

Humidistat: I've got one down in the crawl and I monitor it from my home. I can verify that the RH peaks at around 63% before the dehumidifier knocks it back down. I've got the dehumidifier set to 60% and it's working. I can dial it down, of course.

Re: Smell: I know! I don't understand why I smell anything either! And only when it rains? Super weird. Like I said, I've sealed up my ducts and sealed all the floor penetrations b/t the crawl and the living space with fireblock foam from a can. So I don't have serious air leakage.

There also can't be a chimney effect from the crawl to the attic that comes back into my home because I've air sealed the attic as well.

So... yeah. It's weird. I don't get it. I know that the smell inside my house when it rains is exactly the same as what's in the crawlspace. It's a unique, kinda-but-not-quite musty, kinda-but-not-quite-chemical odor.

I've also found this, which leads me to believe it might be soil gas of some kind: https://crawlspacerepair.com/blog/crawl-space-soil-gas

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #3 on: June 19, 2017, 09:45:24 AM »
Wow, you're in some interesting territory here.  Sounds like you have a soil that is organic rich, still decomposing, and really gets active when wet. I built exclusively on two types of ground, either solid shale, which is nothing but compressed clay, or solid clay that had zero organics in it, and could barely grow a weed, much less decompose to create odors. So,  I have nothing to offer, experience wise, on that.  I can't imagine that a radon fan wouldn't help. Truth be told, they are an extremely easy DIY project that will save $500-1000 over having it done professionally.

Mold is tricky, it will always remain in the core of the lumber. It absolutely will actively grow at RH above 50%, and go dormant below that. I have had to spray entire floor structures (subfloor, joists, beam, etc) with straight bleach from a pump sprayer, to get it under control. I have had customers that had years of a mold free, dry crawl, then get stupid and allow a sump pump to fail, and the joists ended up black and fuzzy again. I don't think that most molds dry up and disappear in low RH, they just go dormant.

I'm impressed by the level of detail you have taken so far with everything. My next step would be to radically crank that RH  down, and keep it peaking at less than 50%. If that doesn't help with the odor, I would buy a Fantech Radon fan and install it.  Given your attention to detail, I assume that you have proper grading and gutters that empty at least ten feet from the structure?

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #4 on: June 19, 2017, 11:41:59 AM »
Wow, you're in some interesting territory here.  Sounds like you have a soil that is organic rich, still decomposing, and really gets active when wet. I built exclusively on two types of ground, either solid shale, which is nothing but compressed clay, or solid clay that had zero organics in it, and could barely grow a weed, much less decompose to create odors. So,  I have nothing to offer, experience wise, on that.  I can't imagine that a radon fan wouldn't help. Truth be told, they are an extremely easy DIY project that will save $500-1000 over having it done professionally.

Mold is tricky, it will always remain in the core of the lumber. It absolutely will actively grow at RH above 50%, and go dormant below that. I have had to spray entire floor structures (subfloor, joists, beam, etc) with straight bleach from a pump sprayer, to get it under control. I have had customers that had years of a mold free, dry crawl, then get stupid and allow a sump pump to fail, and the joists ended up black and fuzzy again. I don't think that most molds dry up and disappear in low RH, they just go dormant.

I'm impressed by the level of detail you have taken so far with everything. My next step would be to radically crank that RH  down, and keep it peaking at less than 50%. If that doesn't help with the odor, I would buy a Fantech Radon fan and install it.  Given your attention to detail, I assume that you have proper grading and gutters that empty at least ten feet from the structure?

Gutters and downspouts are ok. Here's what I'm thinking, though, and please tell me what you think:

1. Do what you're suggesting and dial down the dehumidifier to 50% RH. I actually posted this same question on another forum (HVAC Talk) and someone suggested exactly the same.

2. Seal the vapor barrier to the foundation walls. At present, it's attached via nails/tacks spat out of a Hilti gun. I think I'll get some caulk or mastic and actually stick it to the walls to see if that helps with the odor (assuming it's stinky soil gas that causes it).

Do you think it makes sense to do #2 before installing a radon fan with pipes and all that? There's nothing to lose except time, I guess. I also hate the idea of spending a whole Saturday in my crawlspace and spending $300ish on the radon thing.

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #5 on: June 19, 2017, 03:09:52 PM »
I would definitely caulk first. Just a word of caution here, though. Do some deep research on what caulk/sealant actually sticks to the vapor barrier, long term. I assume that it's standard poly sheeting. If so, I have had nothing but fails trying to get anything to stick to the stuff, including products that clearly claim to do so.  My last attempt was an expensive PL brand construction adhesive that clearly stated that it would work. It did, until it didn't, and all the poly fell off the wall.

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #6 on: June 21, 2017, 08:11:05 AM »
I just talked to a local guy in the crawlspace encapsulation business. He recommended products for sealing the vapor barrier to the wall: Loctite Heavy Duty Power Grap + plastic fasteners or "foundation pins" from crawlspacerepair.com. You use the caulk and then drill holes and tap the fasteners in with a hammer. In his experience, that will hold it to the wall.

He, too, thinks that the problem is some sort of stinky soil gas coming up from the gaps between the vapor barrier and the foundation. Something in the soil is "activated" when it gets wet, hence the smell during rainy weather.

I'll update this thread after I've taken action probably in the next couple of weeks.

AlanStache

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Re: Crawlspace Makes My House Smell
« Reply #7 on: June 21, 2017, 08:43:47 AM »
I have no idea what I am talking about but that wont stop me from typing here :-)
1) Are you sure the odor is coming from the crawl?  Does the outside ever smell similar?
2) If bad things are building up under the vapor barrier could venting from under the barrier to outside solve the root problem (PVC pipes)?  I have never heard of someone doing this and there might be reasons to not do this but if directly trying to block something is not working maybe removing the source of the problem is an option.
3)  If the vapor barrier is just sheets of poly are they sealed to each other in the overlap or just lying on top of each other?
Be the person Mr. Rogers knows you can be.

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #8 on: June 21, 2017, 09:50:55 AM »
I just talked to a local guy in the crawlspace encapsulation business. He recommended products for sealing the vapor barrier to the wall: Loctite Heavy Duty Power Grap + plastic fasteners or "foundation pins" from crawlspacerepair.com. You use the caulk and then drill holes and tap the fasteners in with a hammer. In his experience, that will hold it to the wall.

He, too, thinks that the problem is some sort of stinky soil gas coming up from the gaps between the vapor barrier and the foundation. Something in the soil is "activated" when it gets wet, hence the smell during rainy weather.

I'll update this thread after I've taken action probably in the next couple of weeks.

Cool, I would really like an update later. I didn't look at the cost of the pins, but I have found that tapcons and fender washers work real well, and may be cheaper?  The trick to tapcons is using a battery impact gun to drive them.

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #9 on: June 21, 2017, 07:17:55 PM »
1) Are you sure the odor is coming from the crawl?  Does the outside ever smell similar?
2) If bad things are building up under the vapor barrier could venting from under the barrier to outside solve the root problem (PVC pipes)?  I have never heard of someone doing this and there might be reasons to not do this but if directly trying to block something is not working maybe removing the source of the problem is an option.
3)  If the vapor barrier is just sheets of poly are they sealed to each other in the overlap or just lying on top of each other?

1. Yes, it's coming from the crawl. It's a very unique odor that I've only ever smelled down there. I've never smelled anything else like it anywhere, so that's where it's coming from.

2. Yeah, a lot of people do exactly this. They install what is commonly known as a radon mitigation system to remove stinky soil gases that build up under a vapor barrier. That's actually an option I've been weighing myself, but now I'm not because... well, keep reading the rest of this comment b/c I'm about to explain.

3. Yes, they are. They always should be overlapped and sealed with a special tape.

Cool, I would really like an update later. I didn't look at the cost of the pins, but I have found that tapcons and fender washers work real well, and may be cheaper?  The trick to tapcons is using a battery impact gun to drive them.

Update on this, and a potential game changer: You know that guy in the crawlspace encapsulation business who I mentioned in my last comment who came by my place and gave me some advice? Well, he actually gave me some extra vapor barrier he had a product called Diamondback which is incidentally THE SAME vapor barrier I already have down there.

Ok. So I put the rolled up vapor barrier in the storage area (we call it our "bike garage") that adjoins my deck. That was this morning. I went back into the bike garage later in the day and... BAM! I smelled the crawlspace odor I've been describing in this thread!

I'm now convinced that it's the Diamondback vapor barrier that I'm smelling in my house. It's go to be. The smell is just too damn unique to be anything else.

Here's my theory/solution:

1. I only smell the vapor barrier when it rains because the moisture from below the soil is getting into the air and exacerbating the off-gassing (or whatever you want to call it) from the product. This "stronger" incarnation of the odor makes its way into my ducts and gets blown into the house. My ducts are sealed up tight, but there's always some leakage. It's just the way it is.

2. There are two possible solutions: Rip out the vapor barrier, install a completely new one, and hope it doesn't off-gas, OR install the free vapor barrier that was given to me in spite of its odor and seal it properly to the crawlspace wall to prevent the moisture intrusion described in #1. EDIT: The reason I'd install extra plastic is because it currently doesn't go all the way up the wall; I figure that if I'm going to seal it to the wall, I may as well hang plastic all the way up to about 3" below the sill (to allow for termite inspections).

3. I'll also dial my dehumidifier setting down to 50% RH to further mitigate moisture in the air.

4. Even though I'm basically installing more of the thing I know is stinky, I think this is a better option than ripping it out and starting over because: A). That's a lot more work, and B). A different product might stink too.

Interesting side note: Most people seem to love the Diamondback vapor barrier if you look at comments and reviews online. It's apparently a really heavy duty product. Crawlspacerepair.com seems to be one of the most popular places to buy it, and their website explicitly states that it doesn't off-gas and that it's VOC-free. Not sure I agree!

There's also this forum post where someone claims that the Diamondback vapor barrier is smelly and the owner of Crawlspacerepair.com chimes in to defend the product: http://www.diychatroom.com/f2/odor-crawl-space-140046/index4/

Defense or no defense, I'm positive now that the Diamondback vapor barrier is the source of my odor issue. There's just no other explanation for the smell coming from my bike garage after and only after I shut a roll of Diamondback vapor barrier up in there for 10 straight hours.
« Last Edit: June 21, 2017, 07:36:30 PM by El_Viajero »

BTDretire

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Re: Crawlspace Makes My House Smell
« Reply #10 on: June 22, 2017, 02:12:08 PM »
Arrgh lost my post- long post shortened, make sure you don't have a gas leak in the crawlspace.
I thought I had a mildew smell and it was a gas leak.  The flare in a copper pipe had just corroded and started leaking. 1930s house.

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #11 on: June 22, 2017, 07:11:37 PM »
Arrgh lost my post- long post shortened, make sure you don't have a gas leak in the crawlspace.
I thought I had a mildew smell and it was a gas leak.  The flare in a copper pipe had just corroded and started leaking. 1930s house.

Good thinking. There's no gas here, though. It's an all electric home. There aren't even any lines on the property.

derekjr

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Re: Crawlspace Makes My House Smell
« Reply #12 on: June 22, 2017, 10:01:35 PM »
I've participated in the installation of several enclosed crawl spaces and we install a fan in the crawl space vented to outside.  This fan runs continuously and is set to run at a speed that reverses the stack effect (air moving from crawl to house) under most conditions.  This is also one of the approaches that meets code requirements for unvented crawl spaces.  Here's the section from the IRC:

R408.3 Unvented crawl space.
Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be
required where:
1.   Exposed  earth  is  covered  with  a  continuous  vapor  retarder.    Joints  of  the  vapor  retarder  shall  overlap  by  6  inches  (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend at least 6 inches (152 mm) up the stem wall and shall be attached and sealed to the stem wall; and
2.  One of the following is provided for the under-floor space:
2.1.   Continuously operated mechanical exhaust ventilation at a rate equal to 1 cfm (0.47 L/s) for each 50 ft2 (4.7 m2) of crawlspace  floor  area,  including  an  air  pathway  to  the  common  area  (such  as a  duct  or  transfer  grille),  and perimeter walls insulated in accordance with Section N1102.2.8; 
2.2.   Conditioned air supply sized to deliver at a rate equal to 1 cfm (0.47 L/s)  for each 50 ft2 (4.7 m2) of under-floor area,  including  a  return  air  pathway  to  the  common  area  (such  as  a  duct  or  transfer  grille),  and  perimeter  walls insulated in accordance with Section N1102.2.8;
2.3.  Plenum complying with Section M1601.4, if under-floor space is used as a plenum.


So, if you are going to install an unvented crawl to code, you technically need to open a supply register in your crawl, use it as a plenum for conditioned air, or install a fan and open air pathways between the house and the crawl.  You need to insulate the foundation walls as well.

I'd say that you should follow section 2.1 above, but just skip the intentional air pathway between the crawl and the house.  That is intended to keep the crawl space warmer (and would help with the mold) but will make it more difficult to reverse stack effect.

Get the following materials:
1.  Panasonic Inline Fan -  FV-20NLF1
2.  Two concrete pier blocks with saddles
3.  4' 4"x4" pressure treated post
4.  6" flex ducting (insulated or not, doesn't matter)
5.  Dampered through wall cap 6" (or get a 4" dryer cap and a 6-4" reducer)
6.  Variable speed control

Centrally mount the 4x4 on the pier blocks in the crawl space.  Mount the fan to the 4x4.  Install the cap through the rim joist or one of your abandoned foundation vents.  Duct the fan to outside.  Wire the fan to the speed control... locate it inside your house for convenience of changing speeds or in the crawl for an easier initial install job.  You can attach the fan directly to framing, but mounting it on the pier blocks will make it less than likely to be heard or felt in the house.

Ideally you'd have access to a pressure gauge (manometer) of some sort.  We close everything up and measure the pressure in the crawl with reference to the pressure in the house.  We turn the fan up until the crawl is 1-2 Pa less than the house.  Air will now primarily move from the house to the crawl the majority of the time.  Under extreme conditions, the fan will not overcome stack effect (windy days, large temperature differences) but on the whole air will stop moving from the crawl to the house.  This is will stop any smells and poor indoor air quality associated with crawl space smells.

If you don't have access to any sort of pressure gauge that reads low enough (Pa are a pretty fine unit of measure), I'd just turn the fan up starting at about 1/4 speed and increasing until you stop noticing symptoms.

Make sure you really seal off any penetrations between the crawl and outside.  Don't just plug your foundation vents, seal them.  Seal the seams between the sill and the foundation and the sill and the rim joist.  Seal the subfloor to rim joist seam.  Weatherstrip the crawl access door.  You want to pull air from the house, not from outside.  If you don't seal these areas, it will be difficult to get a good pressure differential between house and crawl.

Some other notes/points of experience:
-  the plastic anchors you mention above from crawlspacerepair.com are the ticket... They hold the vapor barrier in place until whatever sealant your using takes hold... the Loctite you mention above should be fine
-  For energy efficiency sake, you should insulate the walls.  As Paddlehat mentions this technically requires a thermal barrier covering rigid insulation on foundation walls.  Both Hunter and R-max make exposure rated rigid foam that our code officials allow to be exposed in the crawl.  It is Hunter XCI and R-Max TSX-8500.  It is poly-iso foam and one side has a slightly thicker foil facer.  You won't find it at the box stores or local building supply places, but local insulation companies and potentially roofing suppliers should be able to get their hands on it.
-  With a well sealed vapor barrier and a continuously running ventilation fan, I don't think dehumidifiers are necessary.



« Last Edit: June 22, 2017, 10:07:32 PM by derekjr »

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #13 on: June 23, 2017, 05:02:24 AM »
Derekjr. Battling with my local, and clueless, code officials,over crawl space ventilation,  was one of the primary drivers for my decision to end a very successful homebuilding business. The biggest reason was that I had the chance to FIRE, and a sweet pile of cash accumulated to do so, but this whole mess instilled a deep hatred for clueless bureaucrats and the power they can wield. The code sections you cite accurately reflect what a mess the ICC residential code is, and how it fails to address  technology, and mandates stupid, dangerous methods, while masquerading as the standard for life safety. Once you end up administering the thing using bureaucrats who couldn't build a dog house from a precut kit, and worship the IRC book like it's a fucking bible, all is lost. Which is where I found myself a few years ago.

For nearly a decade I built dozens of incredible, sealed conditioned crawl spaces that performed flawlessly. This was in a cold wet region, in heavy clay, where full basements were often full of water, and most crawls were a failed, moldy mess. I used  poured concrete walls, exterior drainage and wall waterproofing, a poured "rat slab" thin concrete floor over a poly barrier, and insulated with R-10 closed cell sprayed urethane on the walls, covered with a fire rated intumescent coating.  I varied from the 2006 & prior code for one reason. I did not use a ducted HVAC system to control the space. I did this for several reasons.  First, these were typically seasonal homes, and if the HVAC wasn't run 24/7/365 the space would not stay conditioned. Second, with the extreme sealing, and insulating, the space would not go below the temperature of the building above, period. So, if you left the place in winter, and the electric baseboard was set at 50*, the crawl stayed at that temp also. Third a dedicated dehumidifier is required in the space for it to maintain a healthy environment. In that heavy, wet clay, ducted HVAC, designed to moderate the living space, will not resolve crawl space moisture issues, not to mention that HVAC, ducted to the crawl is an awesome way to circulate mold, and radon, and distribute it evenly into the living environment.  Since I had local "good old boys" for inspectors at the time, this was fine.  They were good builders who knew that my technique, including everything but the fire coating, was nothing new, nothing I discovered, and had a history of working well in the area, since the 1960s, when it was first tried. (That's no a typo. By the sixties a local contractor was spraying foam for agricultural/cold storage applications, and
decided that it could be useful in crawls. Fifty years ago they would put poly down. Next, they often poured  a rat slab by passing bucket of concrete down to a guy who would hand trowel it, five gallons at a time. they would bang some plywood into the air vent openings, and spray a thin coating of closed cell foam. All this about 30 years before it was discovered by the industry at large)

A few years later as the corruption of the code industry spread to my little corner of the world, and local municipal inspectors are suddenly obsolete, as regional engineering firms weasel into position. They offer to take all the responsibility off the hands of the small  town, and townships and give them lots of money for free. They just triple and quadruple permit fees, then give a cut to the town.  Naturally, this is all administered by scum sucking apparatchiks, who have various degrees, worship the book, and can't find their own ass with two hands and a flashlight. Now the fun starts.

Shortly after the good comrades settle into their desks, my very first set of plans is rejected, with a cut and past section on unvented crawl spaces attached. What they don't know is that competent inspectors have lobbied the IRC for years on a way to allow my system, since it is superior, and there is no need to used ducted HVAC to condition the space, and lots of reason to avoid doing so. The IRC responds with 403.8, a monumentally stupid and dangerous thing to do.

I then ask the head bureaucrat why anybody would ever install the exhaust and air supply, if they had any interest in the health and life safety of future occupants, and if she was willing to accept future liability for this asinine idea. Naturally, she didn't have a clue of what I was asking. So I asked the following questions.

1. We are in a very high Radon area, yet sadly,  there are no IRC requirements for testing and mitigation. Why would I install a system to potential exacerbate radon levels inside the structure?

2. There are stringent fire sealing requirements to isolate the living space from the crawl, sealing of all penetrations, prescribed thickness, and fire rating of floor materials, etc. Yet you are demanding that I cut a 4x10 open vent right through the floor, voiding that barrier, why is this a good idea?

3. In the event of a fire in occupied space,  it is possible to draw flames through the floor vent, through the crawl and out the exterior vent. This could accelerate the fire, and lessen the chance that occupants could escape, are you willing to be responsible for this massively stupid error, in the event of fatalities? Do you know what a duct fire shutter is, and why is it not a requirement?

4. Here in a zone six location, where the biggest energy expenditure is heating, why would anybody want a system that created a vacuum on the exterior envelope of the home, and creates a massive loss of heated air, as tens of thousands of CFM a day are infiltrated into the structure, heated and wasted to the outside? Do you really think that the average new customer isn't calling the builder the first winter of occupancy, and asking why their first heating bill is three times what the neighbors is? Do you really think that 99% of all of these fans are not going to be disconnected within the first year? Then how do you control the crawl? Oh, yea, you seal up the hole where the fan was, and you put a dehumidifier down there.
 
In the end I was building the same great crawl spaces. I would add another dryer vent hood to the band joist, temporarily install a 40 CFM duct fan, and hardwire it in. Then cut a small floor register into a obscure area, like a bathroom linen closet. After the good little drones signed off on my final, I would pull everything but the floor register, and seal the space up properly. Toward the end, one of the  apparatchiks discovers that they can bust some more balls, and generate another fee, by enforcing standard slab requirements on anybody who uses rat slabs. The whole purpose of the rat slab was to have a thin layer of concrete to permanently protect the vapor barrier from wear and damage. Now they want 4" of gravel under, a sealed and inspected vapor barrier, and full 4" slab, like any basement or garage floor. It is totally a waste  to material and money. They could care less, it's "in the book" and they can't let you pour a floor without inspecting the vapor barrier first, so it creates another inspection step that they can bill for.  So, now I'm forced to skip the concrete, and just use plastic. I simply can't take another $1500 of unrecoverable funds out of my pocket, to waste on concrete that nobody will ever see, or need, just so an inspection agency can stick another $75 in their pocket.

In the end I said screw it, enough is enough.  Hopefully, I've made a more important point here. That being don't EVER use continuous, conditioned ventilation to deal with a sealed crawl space. It's stupid and dangerous for many reasons.
« Last Edit: June 23, 2017, 06:03:44 AM by paddedhat »

derekjr

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Re: Crawlspace Makes My House Smell
« Reply #14 on: June 23, 2017, 03:36:11 PM »
Paddlehat, sorry to bring up codes in my post, I do understand that frustration.  I should probably post a trigger warning before referencing codes...

What I believe we agree on:

1.  Code officials and codes can make make the construction industry a nightmare, especially letter of the law only enforcement.  My quoting of the code was not intended to say that an unvented crawl must be done that way.  I included it, because I think that one of the prescriptive approaches they list is mostly solid.  It was certainly not intended as unqualified and ubiquitous support for all codes and code enforcement.

2.  The 2nd and 3rd options listed in the code for unvented crawl spaces are not good and I wouldn't recommend them.

3.  Intentional openings between the crawl and the house are not necessary.  That is why I said he should not cut one in my post.  We've only done one enclosed crawl on a new house, and we did the same things as you.  Cut a hole for the inspector and then sealed it up afterward.

What we probably partially agree on


1.  Continuous crawl space ventilation will be an energy penalty.  There is no doubt a continuously running crawl space fan will cost more in heat... but I think you overstate the impact.  I'm advocating what is essentially a bath fan in the crawl space, usually pulling between 50-150 cfm once set.  That fan is getting air from two spaces... outside and from the main body of the house.  No matter how hard you try, you aren't going to perfectly seal the crawl space from outside.  So some of the air from that the fan is exhausting is coming into the crawl from outside and not causing any energy penalty.  If you are familiar with a blower door, we can use it to identify whether a space is more connected to inside or outside using zonal pressures.  With the blower door running and the house depressurized to 50Pa with reference to outside, you measure in the crawl space with reference to the house.  A reading of -50Pa indicates the crawl is almost entirely connected to outside, i.e. the foundation walls are much leakier than the floor plane.  A reading of 0Pa would indicate that the crawl is almost entirely connected to inside the home and there are lot more openings through the floor plane than there are through the foundation walls.  After enclosing a crawl space we usually see readings from about -10Pa to -20Pa.  That indicates that the crawl is mostly inside but is still somewhat connected to the outside.  A portion of any air the fan pulls is coming straight from outside and is not an energy penalty to the home.

Reducing the stack effect reduces the impact of air leakage on the home.  Under normal conditions air is coming into the house down low through openings in the floor and lower walls and leaving the house up high through the ceiling and upper floor walls.  That ceiling leakage is the highest priority as it is the warmest and most conditioned air.  A fan in the crawl reduces the stack effect and moves the neutral pressure plane up.  Meaning there is a less dramatic stack effect and less pressure differential at the top of the house.  Less high priority hot air leaving from the top of the house.   Run a second floor bath fan non stop during the winter and it will be a much greater energy penalty than running a crawl fan that depressurizes the crawl space first and then slightly depressurizes the house.  Restated:  With the crawl space fan running you leak a little more air total, but leak some cool air at the bottom of the house instead of all heated air at the top of the house.

Dehumidifies use quite a bit of power in their own right.  I don't have anything quantitative to back this up, but I suspect the energy penalty of crawl space fan is not that much greater than that of a dehumidifier in the crawl, depending on the efficiency and fuel of the heating system and how frequently the dehumidifier must run.

I've never had someone complain about their energy bills after enclosing a crawl and using a continuous fan.  And if your humidity in the crawl is low and you don't have any smells, you can just turn the fan off.

That said, unvented crawl spaces are not as energy efficient as conventional approaches... at least in retrofits.  In retrofits you are limited in the amount of wall insulation that you can install and it is impractical to put anything on the ground.  The ground is pretty warm, but still a heat sink during the winter.  The main benefit of enclosed crawls are moisture management and indoor air quality(but only when you use a fan).  And you are increasing the size of the conditioned space.  In new construction, it is easier  to be efficient as you can insulate under the slab and using icfs or similar.

What I don't think we agree on:

1.  A fan in the crawl is dangerous for radon:  If anything it is much safer to have a continuously running fan, which is really what most radon mitigation systems are.  If we are reversing stack effect between the house and crawl and pulling air from the house to the crawl wherever small holes exist, it will be less likely for radon to migrate into the home.  Unvented crawl spaces do amplify the risk of radon, and real radon systems should be installed if the risk is present, but a continuously running fan will only help.  If you do have moisture, mold, or other contaminants in your crawl, a continuously running fan keeps them out of the house.  This is the OP's problem and this is why I suggested this solution.  I don't have the most recent copy of the IRC but the last time I had to apply for a permit, the county folks did reference a portion about radon and required testing be done.  I'm not sure if that was in the actual IRC or our state's supplemental codes.

2.  A fan in the crawl space causes a fire hazard:   I don't see how.  Does a bath fan in a ceiling vented through an attic make the house a death trap?  This is all this is without the actual connection to the living space.  You said if a fire starts in the home the fan will pull the flame into the crawl and accelerate the fire.  This is a small fan, pulling a small amount of air through many small cracks.  It will not be a fire hazard.  The bath fan or your furnace would be far greater risks as they are directly connected to living space.  I think your claim about a fan killing people in a fire is hyperbole.

As for cutting a hole in the floor, I don't advocate it, but for all considerations and unvented crawl is now a normal conditioned space.   That is why you have to use fire rated and exposure rated materials. The unvented crawl is no different than a basement except for its height.  You have a door and stairway to the basement, that is a far greater fire spread danger than 4x10 opening.  In a new house I tested recently, they were required to install fire partitions in the crawl space so that the fire could not spread as quickly throughout the entire crawl.

3.  Dehumidifiers are necessary:  This space should be no different than the rest of your house.  If you don't live in a climate where you need a dehumidifier in your house, you shouldn't need one in your crawl.  If you do, you should address that source of moisture.  If the humidity is too high, it is quite likely that the vapor barrier is not sealed with enough care.  It should sealed at all seams, extend up the foundation walls, and be sealed to the foundation walls and all pier blocks.  What kind of soil and moisture levels are present won't matter if the vapor barrier is installed completely and with detail.

Bringing it back to the original post.  There is a problem of smell in the house from the crawl space.  If they want to avoid that smell.  They should make sure the vapor barrier is well sealed to walls, at seams, and around all piers and other penetrations.  They should then install a fan and depressurize the crawl slightly with reference to the house.  It will stop the smell.  They can turn it off when the smell stops.  It will cause an energy penalty to the heating bills(though not tremendous), it will not be a fire hazard, and it will improve indoor air quality and reduce the risk of radon if it is present.


paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #15 on: June 24, 2017, 05:22:13 AM »
Paddlehat, sorry to bring up codes in my post, I do understand that frustration.  I should probably post a trigger warning before referencing codes...

What I believe we agree on:

1.  Code officials and codes can make make the construction industry a nightmare, especially letter of the law only enforcement.  My quoting of the code was not intended to say that an unvented crawl must be done that way.  I included it, because I think that one of the prescriptive approaches they list is mostly solid.  It was certainly not intended as unqualified and ubiquitous support for all codes and code enforcement.

2.  The 2nd and 3rd options listed in the code for unvented crawl spaces are not good and I wouldn't recommend them.

3.  Intentional openings between the crawl and the house are not necessary.  That is why I said he should not cut one in my post.  We've only done one enclosed crawl on a new house, and we did the same things as you.  Cut a hole for the inspector and then sealed it up afterward.

Honestly, we are having two conversations if you are referring to retrofits, and not new construction. If your not forced to leave a huge hole in the floor, many of my serious concerns fail to apply here. You advocate some really technically questionable ideas, based on code, then admit that you modify things after the inspector leaves? You lost me on this?

What we probably partially agree on


1.  Continuous crawl space ventilation will be an energy penalty.  There is no doubt a continuously running crawl space fan will cost more in heat... but I think you overstate the impact.  I'm advocating what is essentially a bath fan in the crawl space, usually pulling between 50-150 cfm once set.

Have you actually given this any real thought? A continuously operating  150 CFM fan is going to evacuate a standard 2700 sq, ft. house TEN TIMES  a day, 216000 CFM of conditioned air is being removed, and reconditioned, due to poor choices in dealing with crawl moisture.  That is a huge energy load. It also creates a lot of other issues, based on how and where the infiltration is, everything from exterior air that is condensating inside the building's walls, to a pretty uncomfortable amount of leakage for the occupants.


That fan is getting air from two spaces... outside and from the main body of the house.  No matter how hard you try, you aren't going to perfectly seal the crawl space from outside.

Spray two inches of closed cell foam from the concrete floor, up the stem wall, over the band, up the box, and under the floor sheathing, and tell me how many CFMs of leakage the space will allow. It's darn close to zero.

 So some of the air from that the fan is exhausting is coming into the crawl from outside and not causing any energy penalty.  If you are familiar with a blower door, we can use it to identify whether a space is more connected to inside or outside using zonal pressures.  With the blower door running and the house depressurized to 50Pa with reference to outside, you measure in the crawl space with reference to the house.  A reading of -50Pa indicates the crawl is almost entirely connected to outside, i.e. the foundation walls are much leakier than the floor plane.  A reading of 0Pa would indicate that the crawl is almost entirely connected to inside the home and there are lot more openings through the floor plane than there are through the foundation walls.  After enclosing a crawl space we usually see readings from about -10Pa to -20Pa.  That indicates that the crawl is mostly inside but is still somewhat connected to the outside.  A portion of any air the fan pulls is coming straight from outside and is not an energy penalty to the home.

Reducing the stack effect reduces the impact of air leakage on the home.  Under normal conditions air is coming into the house down low through openings in the floor and lower walls and leaving the house up high through the ceiling and upper floor walls.  That ceiling leakage is the highest priority as it is the warmest and most conditioned air.  A fan in the crawl reduces the stack effect and moves the neutral pressure plane up.  Meaning there is a less dramatic stack effect and less pressure differential at the top of the house.  Less high priority hot air leaving from the top of the house.   Run a second floor bath fan non stop during the winter and it will be a much greater energy penalty than running a crawl fan that depressurizes the crawl space first and then slightly depressurizes the house.  Restated:  With the crawl space fan running you leak a little more air total, but leak some cool air at the bottom of the house instead of all heated air at the top of the house.

Dehumidifies use quite a bit of power in their own right.  I don't have anything quantitative to back this up, but I suspect the energy penalty of crawl space fan is not that much greater than that of a dehumidifier in the crawl, depending on the efficiency and fuel of the heating system and how frequently the dehumidifier must run.

Essentially correct, if we are talking about dehumidifers built decades ago, not now. This is similar to how energy codes have changed efficiency on refrigerators. It's nothing to unplug an older fridge or dehumdifier, and see a $25 drop in monthly energy bills. I frequently had new, unoccupied homes with month electric bills in the low thirties, and roughly $25 of that was fees other than power, so $10-$12 a month is a real world number.

I've never had someone complain about their energy bills after enclosing a crawl and using a continuous fan.  And if your humidity in the crawl is low and you don't have any smells, you can just turn the fan off.

That said, unvented crawl spaces are not as energy efficient as conventional approaches... at least in retrofits.  In retrofits you are limited in the amount of wall insulation that you can install and it is impractical to put anything on the ground.  The ground is pretty warm, but still a heat sink during the winter.  The main benefit of enclosed crawls are moisture management and indoor air quality(but only when you use a fan).  And you are increasing the size of the conditioned space.  In new construction, it is easier  to be efficient as you can insulate under the slab and using icfs or similar.

What I don't think we agree on:

1.  A fan in the crawl is dangerous for radon:  If anything it is much safer to have a continuously running fan, which is really what most radon mitigation systems are.  If we are reversing stack effect between the house and crawl and pulling air from the house to the crawl wherever small holes exist, it will be less likely for radon to migrate into the home.  Unvented crawl spaces do amplify the risk of radon, and real radon systems should be installed if the risk is present, but a continuously running fan will only help.  If you do have moisture, mold, or other contaminants in your crawl, a continuously running fan keeps them out of the house.  This is the OP's problem and this is why I suggested this solution.  I don't have the most recent copy of the IRC but the last time I had to apply for a permit, the county folks did reference a portion about radon and required testing be done.  I'm not sure if that was in the actual IRC or our state's supplemental codes.

Logically, the fan should help, but you are now dumping radon laden air out a low dryer vent, quite a bit different than radon mitigation requires, and a potential health issue. It is interesting to me that my radon lab evacuates their crawl, and vents the radon rich air quite a distance from their building. when the vent pops out in the yard,  to not corrupt testing. How healthy is it to dump the radon laden exhaust right under a window, or near a door opening?  As I stated, the larger issue is being forced to do something dangerous and stupid.

2.  A fan in the crawl space causes a fire hazard:   I don't see how.  Does a bath fan in a ceiling vented through an attic make the house a death trap?  This is all this is without the actual connection to the living space.  You said if a fire starts in the home the fan will pull the flame into the crawl and accelerate the fire.  This is a small fan, pulling a small amount of air through many small cracks.  It will not be a fire hazard.  The bath fan or your furnace would be far greater risks as they are directly connected to living space.  I think your claim about a fan killing people in a fire is hyperbole.

Seriously, in my case you are sucking a significant amount of air, down a single vent. Remember, this is new construction, there is very little of the leakage you speak of. It is clearly a fire hazard. An open, unprotected method of air handling, and potentially spreading a fire to  the underside of a floor structure would be a huge red flag in multi-family or commercial occupancies, yet it is encouraged with zero thought according to the IRC, and you? Wrong.Remember, this whole clusterfuck is a "patch" based on the fact that inspectors were demanding a solution to the fact that many homes do not have ducted HVAC as a control mechanism for crawl conditioning. It was done with no real thought and overall it's a collection of bad ideas.

As for cutting a hole in the floor, I don't advocate it, but for all considerations and unvented crawl is now a normal conditioned space.   That is why you have to use fire rated and exposure rated materials. The unvented crawl is no different than a basement except for its height.  You have a door and stairway to the basement, that is a far greater fire spread danger than 4x10 opening.  In a new house I tested recently, they were required to install fire partitions in the crawl space so that the fire could not spread as quickly throughout the entire crawl.

Then why would you advocate that the space be used as an air plenum?  On one hand, my jurisdiction wants a one hour rating (5/8 sheetrock) on the ceiling of the crawl, if you use trusses, or I-joists, and have a source of ignition in the crawl (furnace, gas HWH) OTOH, they are creating a life safety issue with the power venting scheme. And my local officials get a deer in the headlights look when questioned about it. Remember, on new construction, the subfloor is used as a fire separation. All penetrations are sealed with firecaulking, rockwool fire blanket material, etc.. to maintain the integrity of the division. Violating that plane and randomly blowing tens of thousands of CFM of air through uncontrolled space is ridiculous.

3.  Dehumidifiers are necessary:  This space should be no different than the rest of your house.  If you don't live in a climate where you need a dehumidifier in your house, you shouldn't need one in your crawl.  If you do, you should address that source of moisture.  If the humidity is too high, it is quite likely that the vapor barrier is not sealed with enough care.  It should sealed at all seams, extend up the foundation walls, and be sealed to the foundation walls and all pier blocks.  What kind of soil and moisture levels are present won't matter if the vapor barrier is installed completely and with detail.

Sorry, but after years of living in, and building tens of millions of dollars worth of housing stock, in a climate where a dehumidifer below grade is not an option, but required if you want to keep RH below mold growing levels, I disagree. You cannot make statements like that based on experience from other regions, or something you read in a book.

Bringing it back to the original post.  There is a problem of smell in the house from the crawl space.  If they want to avoid that smell.  They should make sure the vapor barrier is well sealed to walls, at seams, and around all piers and other penetrations.  They should then install a fan and depressurize the crawl slightly with reference to the house.  It will stop the smell.  They can turn it off when the smell stops.  It will cause an energy penalty to the heating bills(though not tremendous), it will not be a fire hazard, and it will improve indoor air quality and reduce the risk of radon if it is present.


Advocating for a system that causes a potential of a quarter million cubic feet of unconditioned air, per day,  to be vacuumed into a structure, while dismissing all the issues it brings to the table, is IMHO, not sound in the least, and hazardous to everything from the customer's wallet to life safety. I'm older than most here, and have seen every kind of construction idea imaginable. Many, were the next greatest thing, until they weren't.  When somebody say to me, "We are the new code officers in town, and you are now going to stop doing something with a 50 year record of success, and we will force you to do something dangerous and stupid, I'm not impressed.
 
IMHE, what you are doing is the wrong solution to the problem, and costing the homeowner a lot more than you, or even they, realize. That said, I'm talking about my new construction structures that are using about half the energy of similar, older homes in the same location. A fan in the crawl of an older, leaky home is not nearly as serious as a fan and a hole in the floor of a tight new structure., but there are far better ways to deal with the issue.
« Last Edit: June 24, 2017, 05:30:47 AM by paddedhat »

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #16 on: June 26, 2017, 03:43:44 PM »
So a lot has happened since I first opened this thread a few days ago:

1. I realized that the smell is coming from the vapor barrier. See one of my earlier replies for why I'm positive this is the case.

2. I've been able to trace the source of the smell to the air coming from my ducts. It's not lingering because of air leaks in the floor if I go to the trouble to actually find where it's the strongest, it's always coming from my air ducts.

This leaves me in sort of a dilemma. I've already sealed the living crap out of my return ductwork with actual mastic and high quality mastic tape. I don't know how I could possibly seal the ducts up any tighter, so I don't know how I'll prevent the smell from getting in my house. Adding additional vapor barrier will possibly just exacerbate the problem (since what I've got is the same kind). I'm not sure I'm willing to go the trouble to add vapor barrier and seal it to the foundation to prevent any "activation" of the vapor barrier smell by moisture in the air after it rains because... Hell, it might just smell anyway. And then where would I be?

So I'm contemplating doing the unthinkable. I'm contemplating re-venting my crawlspace.

I know. I know.

This time, I think I might install a system like this one: http://ventthecrawl.com/

The way it works actually makes sense. You seal off all the vents except for two: One for an exhaust fan and another for a "moisture scrubber" that removes most humidity from the makeup air before it circulates around the crawlspace. Over time, the continuous air movement prevents mold growth and lowers the RH of the space. For me, it would do double duty by expelling the stinky air.

I'm more concerned about indoor air quality than energy efficiency in this case, so I'm considering this.

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #17 on: June 26, 2017, 04:06:29 PM »
Interesting system. My concerns would involve installation in a colder climate. The moisture removal is static and relies on condensation created by a temperature differential, essentially the unit is cool by virtue of it's location, and hot, wet air sticks to the interior.  What about all those times when the air is wet, but not particularly hot, or the crawl space isn't cool enough to allow the unit to reach the dew point? How often is the whole system essentially non-functional due to cold temps outside?  If you have very wet fall, or winter weather,  and you are sucking wet, sixty degree air into a sixty degree crawl, where is the temperature differential to create the dew point? What about piping and systems that are not freeze protected, in what essentially becomes an unsealed space?

It may work great in many climates, but then again, who knows?

AlanStache

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Re: Crawlspace Makes My House Smell
« Reply #18 on: June 26, 2017, 06:56:34 PM »
re ducts sealing:

When I was getting quotes one company had a spray in glue thing that the said sealed the ducts from the inside.  They would disconnect the HVAC and plug the vents registers then sprayed some glue into the lines that would find its way into all the leaks.  For 2k it seemed a bit much for me but there might be other uber-hard-core sealing options for you.  This would not address any odor coming through your floor or the source obviously.  trade name was AEROSEAL.
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El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #19 on: June 26, 2017, 07:17:13 PM »
Interesting system. My concerns would involve installation in a colder climate. The moisture removal is static and relies on condensation created by a temperature differential, essentially the unit is cool by virtue of it's location, and hot, wet air sticks to the interior.  What about all those times when the air is wet, but not particularly hot, or the crawl space isn't cool enough to allow the unit to reach the dew point? How often is the whole system essentially non-functional due to cold temps outside?  If you have very wet fall, or winter weather,  and you are sucking wet, sixty degree air into a sixty degree crawl, where is the temperature differential to create the dew point? What about piping and systems that are not freeze protected, in what essentially becomes an unsealed space?

It may work great in many climates, but then again, who knows?

Sensible concern. I actually live in the hot, humid American South (central North Carolina), and I can confirm that my crawlspace is pretty much always cooler than the outdoors during months when the humidity is high. In winter, it's dry as a bone around here.

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #20 on: June 26, 2017, 07:20:10 PM »
re ducts sealing:

When I was getting quotes one company had a spray in glue thing that the said sealed the ducts from the inside.  They would disconnect the HVAC and plug the vents registers then sprayed some glue into the lines that would find its way into all the leaks.  For 2k it seemed a bit much for me but there might be other uber-hard-core sealing options for you.  This would not address any odor coming through your floor or the source obviously.  trade name was AEROSEAL.

Yes, I've heard of Aeroseal. I've also heard that it's super expensive. For $2K or whatever they're asking, it had better be damn effective.

I've used bona fide, sticky slather-on mastic and Hardcast 1402 "Foilgrip" tape all over my return ducts and I still have some leakage.

paddedhat

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Re: Crawlspace Makes My House Smell
« Reply #21 on: June 26, 2017, 08:10:04 PM »

Sensible concern. I actually live in the hot, humid American South (central North Carolina), and I can confirm that my crawlspace is pretty much always cooler than the outdoors during months when the humidity is high. In winter, it's dry as a bone around here.

Yea, that's why I would be a lot more comfortable with their system in your climate.  I have a shit-ton of experience with crawl space issues, but it's in a really wet area of the northeast, seven hundred miles north of you, where winter outside humidity can be dry, but the ground is often still soaking wet, and crawls can be just as wet as if was summer. I would give the idea a shot, specifically since you are convinced that you are dealing with a product that's outgassing, and it would be a lot healthier to move it outside of the building envelope via forced evacuation of the space. I would caution to try to provide intake/exhaust balance leaning toward more supply than exhaust, so as to not draw from the conditioned space above.

Goatistheway2

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Re: Crawlspace Makes My House Smell
« Reply #22 on: June 28, 2017, 09:25:23 AM »
This is to El_Viajero-

The odor problem you are having is not from the DiamondBack barrier. You would know this if you had done any research before trying to lay blame on one of our products. There is plenty written about it, but here is a link to help you understand what is happening in your crawl space- https://www.youtube.com/watch?v=AOUGJ8mxlwo.

We make 15,000,000 sq feet of vapor barrier a year. When we make a product like the DiamondBack vapor barrier, it is made from 100% virgin polyethylene resin and we make about 700-1000 rolls at a time. We have a 40,000 sq ft warehouse in Greenwood SC.
Here are some facts that do not support your claim-
  • Our warehouse does not stink
  • We would not be the highest rated Crawl Space Vapor Barrier Supplier in the US and Canada if our barriers had a smell, any kind of smell
  • You stated that you got the DiamondBack from a contractor friend, why would a friend give you barrier that stinks?
  • Our Manufacturing plant does not have this odor you claim
  • If the roll of DiamondBack did cause the smell there would be 700-1000 other complaints, and there is not
  • If the plastic, DiamondBack or Duraskrim, were causing this odor, why are there not thousands and thousands of complaints? Why has it not been banned in any of the 5 building code revisions?

You are wrong. Your smell is coming form the organic material in the soil under the barrier. You are in the minority of crawl space encapsulating owners that have this problem. You can fix it or you can complain about it, it's up to you.

Other easily found links on the subject-
http://www.americover.com/diy/whats-that-smell-coming-from-my-crawlspace/
https://crawlspacerepair.com/blog/crawl-space-soil-gas

And this from the maker of the popular Dura-Skrim brand vapor barrier (attached as well),

8/28/2012
Raven Industries                                                                                                       
821 W. Algonquin Street
Sioux Falls, SD 57104



To whom this may concern,

Raven Industries is producer of a variety of plastic film products including products that are employed as liners in crawl spaces of residential homes.  In a small number of cases, after a crawl space is lined, feedback is received from the customer stating the liner seems to be generating an off odor. 

The purpose of this letter is to assure our customers, that as manufactured, Raven liners do not produce any odor that is considered disagreeable. In particular, the product line that goes into crawl space applications, the Dura-Skrim line of string reinforced polyethylene material, has been investigated for potential odor generation.  The conclusion of the investigation is that these products are made from components that will not produce a disagreeable odor individually or when in contact with each other in product as manufactured.


Sincerely,



Justin Norberg
Product Development Chemist
Raven Industries
1813 E Ave.
Sioux Falls, SD 57104
(800) 635-3456


[MOD NOTE: You are permitted to defend your product.  MMM has been explicit in the past on this issue.  You will, however, mind your manners while you are here and not treat other members of the forum in this way.  The problem may very well be your product, the installer of your product, the storage location the dealer of your product used or any number of other things.]
« Last Edit: July 02, 2017, 06:37:47 AM by FrugalToque »

El_Viajero

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Re: Crawlspace Makes My House Smell
« Reply #23 on: July 01, 2017, 06:50:07 PM »
This is to El_Viajero-

The odor problem you are having is not from the DiamondBack barrier. You would know this if you had done any research before trying to lay blame on one of our products. There is plenty written about it, but here is a link to help you understand what is happening in your crawl space- https://www.youtube.com/watch?v=AOUGJ8mxlwo.

We make 15,000,000 sq feet of vapor barrier a year. When we make a product like the DiamondBack vapor barrier, it is made from 100% virgin polyethylene resin and we make about 700-1000 rolls at a time. We have a 40,000 sq ft warehouse in Greenwood SC.
Here are some facts that do not support your claim-
  • Our warehouse does not stink
  • We would not be the highest rated Crawl Space Vapor Barrier Supplier in the US and Canada if our barriers had a smell, any kind of smell
  • You stated that you got the DiamondBack from a contractor friend, why would a friend give you barrier that stinks?
  • Our Manufacturing plant does not have this odor you claim
  • If the roll of DiamondBack did cause the smell there would be 700-1000 other complaints, and there is not
  • If the plastic, DiamondBack or Duraskrim, were causing this odor, why are there not thousands and thousands of complaints? Why has it not been banned in any of the 5 building code revisions?

You are wrong. Your smell is coming form the organic material in the soil under the barrier. You are in the minority of crawl space encapsulating owners that have this problem. You can fix it or you can complain about it, it's up to you.

Other easily found links on the subject-
http://www.americover.com/diy/whats-that-smell-coming-from-my-crawlspace/
https://crawlspacerepair.com/blog/crawl-space-soil-gas

And this from the maker of the popular Dura-Skrim brand vapor barrier (attached as well),

8/28/2012
Raven Industries                                                                                                       
821 W. Algonquin Street
Sioux Falls, SD 57104



To whom this may concern,

Raven Industries is producer of a variety of plastic film products including products that are employed as liners in crawl spaces of residential homes.  In a small number of cases, after a crawl space is lined, feedback is received from the customer stating the liner seems to be generating an off odor. 

The purpose of this letter is to assure our customers, that as manufactured, Raven liners do not produce any odor that is considered disagreeable. In particular, the product line that goes into crawl space applications, the Dura-Skrim line of string reinforced polyethylene material, has been investigated for potential odor generation.  The conclusion of the investigation is that these products are made from components that will not produce a disagreeable odor individually or when in contact with each other in product as manufactured.


Sincerely,



Justin Norberg
Product Development Chemist
Raven Industries
1813 E Ave.
Sioux Falls, SD 57104
(800) 635-3456

Dude. Chill.

For starters, this is condescending as hell:

"You would know this if you had done any research before trying to lay blame on one of our products."

Yeah, I haven't done any research. None. I'm just a mouth-breathing know-nothing who came here to talk smack about your precious plastic. Did you read my original post or any of the comments I contributed to this thread? I've been researching the shit out of this. I already thought the problem had to do with soil gases FROM THE VERY BEGINNING OF THIS DISCUSSION. I'd already seen your video and read the other links you included long before coming here for advice. Long story short: I've done the research.

Also, there's this: "You can fix it or you can complain about it, it's up to you."

I haven't complained about anything. You, however, appear to have a colossal chip on your shoulder. You also used a pretty ugly comma splice in that sentence.

Here's what's up:

1. I have a very unique and unusual smell in my crawlspace.
2. The same smell enters my home during wet weather.
3. I didn't know what it was. I figured it was soil gas per some of the literature you've cited here (already seen it).
4. The type of vapor barrier in my crawlspace is a thick, white-on-top, black-on-bottom product ordered, I've since found out, from crawlspacerepair.com. It is known as "Diamondback."
5. I was just loaned a half-roll of the exact same vapor barrier Diamondback ordered from crawlspacerepair.com by a local contractor/acquaintance, who, it turns out, is the same person who installed the initial vapor barrier. I might have forgotten to mention it earlier, but that's how I know it's the same product. This was the guy who put it in initially.
6. I put said roll of Diamondback in my storage shed and shut the door.
7. I came back into my storage shed later in the day and was overwhelmed by THE SAME EXACT UTTERLY UNIQUE SMELL that's always in my crawlspace and occasionally makes its way into my house.
8. #7 above was an above-ground event. No soil gases could have contributed.
9. Based on #s 7 and 8 above, I concluded (as any rational person would) that the vapor barrier itself is causing the smell that's vexing me.

Given the experience I just described, is it unreasonable for me to suspect that the vapor barrier causes the smell? That's not a rhetorical question. I'd really like an answer.

Here are some other (unlikely) possibilities:

Possibility 1: The contractor has a stinky-ass garage and the vapor barrier absorbed the odor.
Possibility 2: The vapor barrier is normally odor-free, but there was this one bad batch that made its way to me.

Got any more? That's all I can think of.

Look, I'm not trying to badmouth this product. Most people apparently don't think it stinks. That's great. Maybe theirs doesn't. The roll of Diamondback that's in my storage shed DEFINITELY DOES stink, though.

Here's another thing to note (as I'm paying close attention to this smell now and thinking more and more about when/why I smell it): We just had a spell of dry-ish/low humidity days and I didn't smell the vapor barrier in my storage shed at all. On the day I smelled it big time the first day it was in there the weather was super wet and humid. This experience is consistent with my experience of smelling it in my home only during wet weather. My hypothesis is that something about the vapor barrier is "activated" when there's a lot of moisture in the air. The moisture makes the plastic omit a more powerful smell than it does normally.

Honestly, I just want this damn smell to go away. I don't care if it's a vapor barrier, soil gas, or possums farting under my house. Whatever it is, I want it gone.  I'm not pointing fingers at the vapor barrier because I want to complain about a product. I'm pointing fingers at the vapor barrier because I have a rational, empirical reason to believe it's the source of the odor.