Comments on: High Humidity in a Spray Foam Attic, Part 2 https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/ Building science knowledge, HVAC design, & fun Tue, 10 Aug 2021 14:31:51 +0000 hourly 1 https://wordpress.org/?v=6.6.2 By: George https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-13329 Mon, 03 Aug 2020 03:03:02 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-13329 In reply to Jamie Kaye.

Jamie
Jamie

I have a home 14 years old home in Florida. Foam in the attic with really high humidity. Ducts sweating and having to keep my thermostat at 70-72 just to keep my humidity in the mid 60’s in my home.

Should I add a small supply in the attic? Maybe a 8x4x4?

Maybe add an 80 CFM exhaust fan in the attic?

Any help would be appreciated. Been dealing with this for many years

]]> By: Kerri Hodgkins https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-12629 Sun, 01 Dec 2019 14:19:12 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-12629 In reply to B.

We have been having air
We have been having air quality issues with our 13 year old spray foam house. We are fairly certain that are only option may be to get rid of it. We would greatly appreciate more of your insights before proceeding with removal.
Thank You

]]> By: George hall https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-12404 Wed, 24 Jul 2019 03:41:04 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-12404 3850 sf new closed cell foam
3850 sf new closed cell foam hoist with high attic humidity. Ac rheem variable speed 18 seer house 72 humidity 53-55%, attic 75,humidity 70+% how do I get humidity out of attic separate portable 70 pt units or one whole house dehumidifier

]]> By: Laureen https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-11796 Sun, 14 Oct 2018 05:00:04 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-11796 In reply to cory.

Cory, did you ever get an
Cory, did you ever get an answer to your question? We live in Mi and have a similar problem and would love to know what you may have discovered.
Thanks

]]> By: Robert https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-11593 Wed, 01 Aug 2018 16:53:53 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-11593 I have a large attic space.
I have a large attic space. On each end of the peak, I have an exhaust fan that activates by temperature control. I recently added a ridge vent. Now I am concerned if adding the ridge vent was a wise idea since when the exhaust fans are running, are they also pulling in moist air through the ridge vents thus defeating the effectiveness of the fans?
Please help me understand whether adding the ridge vent helped or hindered the attic moisture situation. Thank you.
Robert

]]> By: M Schnee https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-11534 Mon, 09 Jul 2018 04:52:59 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-11534 We used open cell spray foam
We used open cell spray foam in our large attic to combat issues we has with condensation (ice) in the underside of the roof decking and gables.

Build and building code inspector thought spray foam was the best option. We created an invented system, closing the ridge and soffit vents. Helped some, but we had issues in the walls too. So we retrofitted the walls with spray foam. No more leaking into the house and down the exterior.

The only lingering problem we have now is on warm days. The attic is very warm and humid. I am concerned about roof rot.

What are some options that will not break the bank? Run a supply and return vent? Add rigid insulation panels over the spray foam?

Not quite time for roof replacement- it is 14 years old. We live in southeast Michigan.

Well researched suggestions appreciated. Would like to avoid damage or collapse of the roof structure down the road.

]]> By: Preston Rogers https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-11448 Thu, 28 Jun 2018 07:57:14 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-11448 What about zone 4 in
What about zone 4 in northeast Georgia? You say Joe’s recommendations were approved for zones 1,2,3. Zone 5 is known for issues. Constructing a new house here and have 3 1/2” of open cell in 2×4 walls and 7” average on the roof decking. After installation, I see these articles of problems. Haven’t covered with my interior paneling yet and still have time to make changes of neccasary and can even remove it if needed (pain in the butt and several thousand wasted). Help, I need answers quick. It’s been installed for a week and I still have a few smell issues and I get a slight headache when I’m the house also which scares me about mixing my house air and attic air through a supply and return to the HVAC. And In the spring and fall we may go a few weeks at time with the doors and windows open enjoying the outdoors. In those times Could you just run the fan on your air handler to circulate the air in the attic given you have a supply and return up there a few hours a day? I’m nervous and considering having someone come get this out of my house and go back to a vented attic which will require some modifications to my soffit, siding and ridge.

]]> By: cory https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-10314 Mon, 13 Feb 2017 22:59:00 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-10314 hi allison/all,I live in
hi allison/all,I live in chicago in a 100 year old house i turned my unused attic into a bedroom for my 2 young daughters and used 6 inches of open cell foam directly to the old wood on the underside of my roof i didnt use a vapor retarder before the drywall was installed i have a separate A/C and furnace installed to take care of the attic space i was reading all the horror stories and didnt do proper research before having it installed and now am just curious to how bad im screwed with no vapor retarder and my furnace dosent have fresh air intake on it but the rest of my house is ballon framing so its not an air tight house just the attic roof. any comments or suggestions would be much appreciated loosing a lot of sleep over this thinking about how bad i could of messed up my house thanks all

]]> By: B https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-10249 Wed, 18 Jan 2017 18:38:57 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-10249 In reply to Ken.

What you smell is the product
What you smell is the product of a hydrocarbon-based chemical with amine catalysts breaking down. All foam products break down over time regardless of what any manufacturer tells you. The higher the water vapor (RH), the more off-gas chemical gets transferred in the air you breath. The fix…get rid of all of it. Trust me!

]]> By: David Butler https://www.energyvanguard.com/blog/high-humidity-in-a-spray-foam-attic-part-2/#comment-9624 Sun, 13 Nov 2016 01:51:45 +0000 http://energyvanguard.flywheelsites.com/?blog_post=high-humidity-in-a-spray-foam-attic-part-2#comment-9624 @Ken, good question and one I
@Ken, good question and one I can’t answer. My recommendation (and presumably the source of your posit) was Joe’s research and testing, and his proposed code change to IRC R806.5 to eliminate the impermeable insulation requirement in CZ1-3 when combined with an air impermeable vapor diffusion port. I’d have to go back and re-read the papers but I think the rationale is that thermal and hygric buoyancy (see ping-pong paper) tend to trump vapor drive, which is the force that would cause vapor to move through air impermeable materials.

The only way I know to confirm the source of your moisture would be to monitor indoor, attic and outdoor temperature and absolute humidity (e.g., dew point) over some period of days, ideally covering a period of changing weather.

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