Closed cell spray foam - Brands


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Old 02-04-16, 10:20 AM
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Closed cell spray foam - Brands

I am looking for closed cell spray foam to apply around my foam board for closing my crawl space vents. However, after googling, all I seem to find are kits. All I need are just a few cans. Hoping someone can provide some brand names that sell close cell spray foam by the can. Thanks!
 
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Old 02-04-16, 05:00 PM
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Why would you be closing the vents in your area?
Vapor barrier on the grade, automatic vents and you would have been fine.
What's the real issue your dealing with?
 
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Old 02-05-16, 03:44 AM
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Relative humidity in my crawl space hovers around 70-75%. There is a VB but poorly installed. I have closed and covered the vents with rigid foam and I am also running a dehumidifier on a timer for appx 10hrs a day which lowers the humidity to around 65%. I am hoping that replacing and properly installing a new VB and sealing the vents will allow me not run the dehumidifier. External humidity is above 60% the vast majority of the time so automatic vents would not benefit me.
 

Last edited by Back40; 02-05-16 at 04:29 AM.
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Old 02-05-16, 06:54 AM
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I live in the land of mold and fungus, the outside relative humidity is usually in the 70% or higher range. My crawlspace is ventilated, I even have a small fan to increase the airflow through the space so while I have never checked, I suspect the RH is always pretty close to the outside RH, which currently (5:48 AM) is 96% at the Weather Underground station less than a mile away. I have ZERO problems normally related to high RH in my crawlspace. My indoor RH is currently at 40%

I don't have the best VB in my crawlspace either, just 6-mil black polyethylene plastic that stops at the foundation walls and is poorly wrapped around the support piers. The edges of the sheets are not sealed in any way and the overlap is insufficient, some areas pulled apart to the point of showing earth. I see no reason to run a dehumidifier to try to attain a lower RH in your space.

Your mileage may vary.
 
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Old 02-05-16, 07:41 AM
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I have learned that the coast of WA is definitely a different environment, but despite Joel's apparent success I would hesitate to recommend those high humidity levels as an acceptable status quo.

A couple of questions:
Did you air seal the foundation to rim in that space? If not, that can be a significant source of outside humid air.
Also, I assume you run ac in the summer and heat in the winter. Sealing the vents, covering the foundation walls and wood rim with insulation, and covering the floor with a vapor barrier, are all brought together by conditioning that space just as you do your house.

If you have seasons when the moisture in the outside air is low, then you could consider opening the vents just like you might open a window in your house when heat or ac is not necessary.

As for sealing those vents, if you are going to add rigid foam over the rest of the foundation, then you can just omit cutting out for the window. Or cut out for the window and attach a larger piece of rigid over that opening with foil tape.

If you need to have the rigid covered with an ignition barrier, locate some Dow Thermax as it is rated to be used as is (if local codes approve it).

Bud
 
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Old 02-05-16, 08:53 AM
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I have learned that the coast of WA is definitely a different environment,...
To be honest, I live about 100 miles inland from the coast. Still, it is considered a West Coast Marine climate (Marine West Coast Climate) and it IS significantly different from most of the US.

I do agree that the sealed, if properly done, crawlspace is the preferred ideal but ventilated crawlspaces are the norm here and for the most part are not a problem. A properly sealed crawlspace is not only sealed from the outside but is also semi-conditioned from the home's heating and cooling systems. You must have a certain minimum of air exchange from the crawlspace to the living space. No floor insulation is necessary but insulating any "above grade" foundation walls is important. The one part that has many people, including experts, confused is where and how to provide vapor retardants to the walls in a manner that does not trap moisture in the wall insulation. Of course this crawlspace insulation is not a huge deal in my climate as it just plain doesn't get that cold. We haven't had any lowlands snow for the last two winters and this winter is looking to be lacking in snow as well, even though we have had a fair amount in the mountains, only thirty some miles east of me.
 
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Old 02-05-16, 10:53 AM
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My crawl space had been vented for apprx 15 yrs. In that time the hardwood floors were constantly buckling at the joints due to the humidity in the crawl space. The moisture in the floor joists was also above normal per a termite inspector. In addition, termite damage was discovered and has been repaired. So it made sense to me to take steps to reduce the humidity in my crawl space. Since I closed the vents and installed the dehumidifier, the wood floors are no longer buckling and the wood moisture is in the normal range. I am just attempting to improve on the sealing of the crawl space in hopes of eliminating the need to the dehumidifier. I am also considering installing an air inducer to provide conditioned air to the crawl space.
 
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Old 02-05-16, 11:27 AM
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Bud,

I have not sealed the foundation to the rim. Would you mind explaining what this entails? I had only planned on running the VB up the walls to a few inches below the top of the walls. I forgot to mention that I have a humidistat controlled exhaust fan with louvers installed in the crawl door. This was my first experiment to improve air flow and reduce humidity in the crawl space. However, this did not significantly lower the humidity in the spring, summer and fall months.
 
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Old 02-05-16, 01:11 PM
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Typically the house rests on a sill plate, pressure treated 2x6, laying flat on top of the foundation wall. Then the floor joists go on top of that forming the deck for the first floor. The perimeter of this deck is the rim joist, the cavity just above the foundation.

Now, where the sill plate sits on the foundation regardless of how they tried to seal it, it leaks lots of air. Where the rim joist rests on the sill plate is also a problem area and it extends up behind the end of every joist because we can no longer access that area.

Solution is to caulk or foam the entire rim joist cavity and where the sill plate rests on the foundation. Your house will have similar spaces and if accessible you can often detect the cold air with your hand. We use an infrared camera.

Then, since you should be conditioning this space with the air from your house, the rim cavities should be insulated along with the inside of the foundation walls. Rigid foan=m insulation is the method most used.

Details as needed
Bud
 
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Old 02-05-16, 01:49 PM
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I have site-finished (as opposed to pre-finished) oak floors in my kitchen, dining area and entryway. I have had none of the problems you cite. Maybe I'm lucky or maybe it is my climate. I have read about other people that live more in the heartland having the same problems with their floors as you described.
 
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Old 02-05-16, 02:19 PM
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How the flooring reacts to moisture may have to do with how it was acclimated. If the op flooring was dry when installed it would not want to see high humidity. I would bet your installers knew your climate was going to be humid so that is what they planned for.

Bud
 
 

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