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chris saunders Posted: Dec 04, 2008 09:05 PM	60+% humidity in closed system I'm back guys! It's been 2+ months since I had closed cell foam sprayed in my foundation, walls and roof cavity. My hardwood floor guy suggesyted I get my humidity where I wanted it before he started. Well, after buying a cheap hygrometer, I've discovered my humidity level runs between 55% when the dehumidier is running to 63% when it gets full. Help! How can I get the moisture out of my house? Where can it all be coming from? This is a lake house, but I can't imagine that is relevant. Thanks in advance, Chris
SprayFoamSupply.com Posted: Dec 04, 2008 09:41 PM	What is on the floor of your basement? If it is poured concrete, did you install a vapor barrier under the concrete?
chris saunders Posted: Dec 05, 2008 06:06 AM	sorry, no basement. home is on pillars with 18 inch crawlspace, dirt floor. closed cell foam was sprayed around perimeter of crawlspace. the only vapor barrier is the black felt paper installer is using on floors. the old subfloor of tongue and groove hem fir is still down also.
Jim Coler Posted: Dec 05, 2008 06:50 AM	Dirt Floor!!!!! Well, even a dry crawlspace floor can emit 10 gallons of moisture a day. So, you need a vapor barrier on the floor of your crawlspace, especially since you sealed up the crawlspace walls to allow for dry air in the winter to come in and dry out the crawlspace. For other areas of moisture, consider where you have an opening to the outside (including through the ground) and think if moisture can come through that space and how much. Also consider your heating source. If you have an unvented propane combustion appliance like a salamander heater, ventless heater, gas stove, etc. these emit a lot of moisture too. Other than that, it could be coming from the wood which absorbs water from the construction process and is tryingt o release it, but it has now where to go once it reaches a certain point within the house. Keep us informed.
SprayFoamSupply.com Posted: Dec 05, 2008 09:00 PM	I am confused, you said that you had the foundation sprayed, but then you said home is on pillars. Is your house on pillars open underneath? Nothing closing the crawlspace under your house? Where is the house? Climate? George
Melvin Chandler Posted: Dec 05, 2008 10:32 PM	Not answering for the guy but sounds like the house was built on pillars but was enclosed (crawl space). Maybe it has a block wall around the foundation and block pillars in the middle. We see some homes built like that here in the mountains where there's a huge drop off of a side of a hill and they get some long posts in the ground to build off of and then enclose the perimeters to keep out air and critters.
chris saunders Posted: Dec 06, 2008 06:31 AM	sorry for confusion guys. house is located on Conesus Lake in western New York. It was originally a cottage. I have converted it to my retirement home. It's a 1200 sq ft ranch, built on pillars, only 18 inches or so off the ground. It was enclosed several years ago with ribbed fiberglas sheeting and styrofoam sheets. When I had the sprayfoam done, it was suggested that I spray up against the "crawlspace" wall to keep all cold out and keep floors warmer, giving me a true closed system. For the 2 months that my furnace has been on, every morning there is approx 1-2 inches of condensation on the bottom of every window and door. I have a 220cfm fan that pulls from both bathrooms for 2 hours a day on a timer.
SprayFoamSupply.com Posted: Dec 06, 2008 10:30 PM	So the crawlspace perimeter walls are sprayed, but not the underside of the floor? I would guess that the moisture is coming up from the ground into the crawlspace and up through your floor into the house.
Roger Morrison Posted: Dec 07, 2008 05:02 PM	You need to install a vapor retarder (Class II or better--less than 1.0 perm) on the ground and seal it to the crawlspace edges and any ground penetrations. The building code classifies this as an unvented crawlspace and requires that a minimal amount of air circulate through the crawlspace to help remove any moisture that gets past the vapor retarder.
Posted: Dec 08, 2008 07:24 AM	2" closed cell down on the grade will get you the perm ratein you need and also afford you a nice way to make seamless transitions to the sides and other penetrations,, would also get you additional work in the crawlspace,,, 'dude
Jim Coler Posted: Dec 11, 2008 01:45 PM	csaunders, Are you the SPF contractor or the homeowner on this project? How and where are you measuring the RH? If the outside walls are sealed up, you need to have a vapor barrier on the floor, otherwise you just have too much moisture coming up through the gorund. Sounds like it's on a lake too which depending on ground water level can add even more moisture.
chris saunders Posted: Dec 14, 2008 09:28 PM	Thanks, guys. i was out of town for a week. I am the homeowner. Now that the perimeter has been sealed, there is no access to the crawlspace and all my hardwood floors have been installed throughout. RH is being measured in living room and in bedroom. Just checked tonite-58%. I'm not sure how good hygrometer is. i may try a different one. Assuming RH is accurate, what else might I try?Could this lead to health and mold problems? Thats my biggest concern, Chris
Gerry Wagoner Posted: Dec 23, 2008 03:16 PM	Hello Roger. Good to see you on here. Gerry
chris saunders Posted: Dec 23, 2008 03:47 PM	i can't get straight answers from my installer. that is why i turned to you guys..assuming my RH is 58%, what should i consider doing before mold starts? is my only option to tear out the foam allow outsides of crawlspace and dig it out deep enough to get a coat of poly in there? What about an air to air heat exchanger or a dehumidifier built into the furnace? thanks 4 all your help so far. i really do appreciate having this site available. Chris
Roger Morrison Posted: Dec 29, 2008 09:12 AM	As I understand the situation, you have a crawlspace that has been insulated with spray foam on the crawlspace walls and the crawlspace is unvented to the outside. I also understand that you have no access to the crawlspace. If this is all true, I recommend that you cut and access hatch through the floor (in a closet or some other place it won't show) and install a vapor retarder on the ground in the crawlspace. Then I would install a ventilation fan and return air path vent to provide 1 cfm of air per 50 square ft of crawlspace area between the occupied space and the crawlspace. See 2006 International Residential Code Section R408.3.
Greg Pruitt Posted: Mar 09, 2009 06:02 AM	I have done several of these houses. YOu do need the poly on the ground. If not, your flooring will bcukle ar be raissed on the edges..Have seen it on an open foundation without poly. YOu culd spray foam on the underside of the sub floor, and solve this problem, but you would still have mold and mildew in the crawl space. For better reference, go to www.raisedfloorliving.com. Good luck, Greg

Author

Comments

chris saunders

Posted: Dec 04, 2008 09:05 PM

60+% humidity in closed system

I'm back guys! It's been 2+ months since I had closed cell foam sprayed in my foundation, walls and roof cavity. My hardwood floor guy suggesyted I get my humidity where I wanted it before he started. Well, after buying a cheap hygrometer, I've discovered my humidity level runs between 55% when the dehumidier is running to 63% when it gets full. Help! How can I get the moisture out of my house? Where can it all be coming from? This is a lake house, but I can't imagine that is relevant. Thanks in advance, Chris

SprayFoamSupply.com

Posted: Dec 04, 2008 09:41 PM

What is on the floor of your basement? If it is poured concrete, did you install a vapor barrier under the concrete?

chris saunders

Posted: Dec 05, 2008 06:06 AM

sorry, no basement. home is on pillars with 18 inch crawlspace, dirt floor. closed cell foam was sprayed around perimeter of crawlspace. the only vapor barrier is the black felt paper installer is using on floors. the old subfloor of tongue and groove hem fir is still down also.

Jim Coler

Posted: Dec 05, 2008 06:50 AM

Dirt Floor!!!!! Well, even a dry crawlspace floor can emit 10 gallons of moisture a day. So, you need a vapor barrier on the floor of your crawlspace, especially since you sealed up the crawlspace walls to allow for dry air in the winter to come in and dry out the crawlspace. For other areas of moisture, consider where you have an opening to the outside (including through the ground) and think if moisture can come through that space and how much. Also consider your heating source. If you have an unvented propane combustion appliance like a salamander heater, ventless heater, gas stove, etc. these emit a lot of moisture too. Other than that, it could be coming from the wood which absorbs water from the construction process and is tryingt o release it, but it has now where to go once it reaches a certain point within the house.

Keep us informed.

SprayFoamSupply.com

Posted: Dec 05, 2008 09:00 PM

I am confused, you said that you had the foundation sprayed, but then you said home is on pillars. Is your house on pillars open underneath? Nothing closing the crawlspace under your house? Where is the house? Climate?

George

Melvin Chandler

Posted: Dec 05, 2008 10:32 PM

Not answering for the guy but sounds like the house was built on pillars but was enclosed (crawl space). Maybe it has a block wall around the foundation and block pillars in the middle. We see some homes built like that here in the mountains where there's a huge drop off of a side of a hill and they get some long posts in the ground to build off of and then enclose the perimeters to keep out air and critters.

chris saunders

Posted: Dec 06, 2008 06:31 AM

sorry for confusion guys. house is located on Conesus Lake in western New York. It was originally a cottage. I have converted it to my retirement home. It's a 1200 sq ft ranch, built on pillars, only 18 inches or so off the ground. It was enclosed several years ago with ribbed fiberglas sheeting and styrofoam sheets. When I had the sprayfoam done, it was suggested that I spray up against the "crawlspace" wall to keep all cold out and keep floors warmer, giving me a true closed system. For the 2 months that my furnace has been on, every morning there is approx 1-2 inches of condensation on the bottom of every window and door. I have a 220cfm fan that pulls from both bathrooms for 2 hours a day on a timer.

SprayFoamSupply.com

Posted: Dec 06, 2008 10:30 PM

So the crawlspace perimeter walls are sprayed, but not the underside of the floor? I would guess that the moisture is coming up from the ground into the crawlspace and up through your floor into the house.

Roger Morrison

Posted: Dec 07, 2008 05:02 PM

You need to install a vapor retarder (Class II or better--less than 1.0 perm) on the ground and seal it to the crawlspace edges and any ground penetrations. The building code classifies this as an unvented crawlspace and requires that a minimal amount of air circulate through the crawlspace to help remove any moisture that gets past the vapor retarder.

Posted: Dec 08, 2008 07:24 AM

2" closed cell down on the grade will get you the perm ratein you need and also afford you a nice way to make seamless transitions to the sides and other penetrations,,
would also get you additional work in the crawlspace,,,
'dude

Jim Coler

Posted: Dec 11, 2008 01:45 PM

csaunders,
Are you the SPF contractor or the homeowner on this project? How and where are you measuring the RH?

If the outside walls are sealed up, you need to have a vapor barrier on the floor, otherwise you just have too much moisture coming up through the gorund. Sounds like it's on a lake too which depending on ground water level can add even more moisture.

chris saunders

Posted: Dec 14, 2008 09:28 PM

Thanks, guys. i was out of town for a week. I am the homeowner. Now that the perimeter has been sealed, there is no access to the crawlspace and all my hardwood floors have been installed throughout. RH is being measured in living room and in bedroom. Just checked tonite-58%. I'm not sure how good hygrometer is. i may try a different one.
Assuming RH is accurate, what else might I try?Could this lead to health and mold problems? Thats my biggest concern, Chris

Gerry Wagoner

Posted: Dec 23, 2008 03:16 PM

Hello Roger. Good to see you on here.

Gerry

chris saunders

Posted: Dec 23, 2008 03:47 PM

i can't get straight answers from my installer. that is why i turned to you guys..assuming my RH is 58%, what should i consider doing before mold starts? is my only option to tear out the foam allow outsides of crawlspace and dig it out deep enough to get a coat of poly in there? What about an air to air heat exchanger or a dehumidifier built into the furnace? thanks 4 all your help so far. i really do appreciate having this site available. Chris

Roger Morrison

Posted: Dec 29, 2008 09:12 AM

As I understand the situation, you have a crawlspace that has been insulated with spray foam on the crawlspace walls and the crawlspace is unvented to the outside. I also understand that you have no access to the crawlspace.
If this is all true, I recommend that you cut and access hatch through the floor (in a closet or some other place it won't show) and install a vapor retarder on the ground in the crawlspace. Then I would install a ventilation fan and return air path vent to provide 1 cfm of air per 50 square ft of crawlspace area between the occupied space and the crawlspace. See 2006 International Residential Code Section R408.3.

Greg Pruitt

Posted: Mar 09, 2009 06:02 AM

I have done several of these houses. YOu do need the poly on the ground. If not, your flooring will bcukle ar be raissed on the edges..Have seen it on an open foundation without poly. YOu culd spray foam on the underside of the sub floor, and solve this problem, but you would still have mold and mildew in the crawl space. For better reference, go to www.raisedfloorliving.com. Good luck, Greg

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