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Spray foam sounds good at first but it's almost always complete trash. Nasty chemicals, 0 ventilation, poor humidity management, pain in the ass to remove. It's

Spray foam sounds good at first but it's almost always complete trash. Nasty chemicals, 0 ventilation, poor humidity management, pain in the ass to remove. It's one of these things poor people get because it's cheap upfront but in the end it'll cost you twice as much as a proper insulation system It's easy to apply and looks cool so that's good for instagram builders/remodelers, plus they'll probably be out of business before you notice the damage. https://vtdigger.org/2023/05/22/i-wanted-to-cry-devastating-risks-of-spray-foam-insulation-hidden-from-vermont-homeowners/ https://vtdigger.org/2023/05/22/i-wanted-to-cry-devastating-...

jordanb 2y ago
I have an interest in metal boats and in the 70s-80s it was common to spray foam these vessels. This pretty much always caused premature end of life due to corrosion. There's a whole class of corrosion in metal structures called Corrosion Under Insulation or CUI. This is a problem for any insulated metal structure, but it is way worse with spray foam because the foam traps moisture very effectively, when it breaks down it becomes acidic, it is difficult to remove for inspection or repair, and it makes hotwork dangerous because it is flammable. When I started seeing wooden houses and roof decks get spray foamed, I could only think that these structures will likely be rotten and useless in 20-30 years. I would only sprayfoam something if the substrate is completely impervious to moisture, like if it was fiberglass or something. Even then you're likely looking forward to a pretty evil concoction under that insulation in a decade or so.
- yobbo 2y ago
  Some fibreglass boats are still filled with spray-foam, and it has the known effects of eventually causing rot to any wood that might be embedded in the fibreglass. Embedded plywood is much less common nowadays though. (The foam cores in modern fibreglass construction is PVC-based, moisture safe, and can not be sprayed.)
xnx 2y ago
Really? Properly installed closed-cell spray foam seems to have a ton of benefits: Moisture barrier: It blocks water vapor and prevents mold growth by reducing humidity levels in crawl spaces and other areas. Structural strength: It can double the racking load of a home, making it more resistant to severe weather. Air sealing: It protects against drafts, cold spots, and uneven heating. Longevity: It retains its R-value over time and can last for decades if installed correctly. Energy cost savings: It reduces your carbon footprint by consuming less energy. Improved air quality: It doesn't contain harmful micro substances like fiberglass insulation.
- lm28469 2y ago
  Moisture barrier: it traps the humidity in places you potentially don't want to Structural strength: yeahhhh... no Longevity: not more than anything else, a pain in the ass to replace though Improved air quality: The petrol derivate foam that leaves a god awful nasty smell for days/weeks and can offgas for years is good for air quality ? rock or better sheep wool is much better in that regard In the end of the day people do whatever they want but I'd rather build smaller and spend more on rockwool than have extra space and nasty ass foam all around my house
  - xnx 2y ago
    > Moisture barrier: it traps the humidity in places you potentially don't want to Definitely a risk with any type of improperly installed moisture barrier (like ZIP sheathing). > Structural strength: yeahhhh... no It would take me some time to find more formal studies, but there are a lot of videos on YouTube that demonstrate the addeded strength. Here's one: https://www.youtube.com/watch?v=4mMHJpSHKJM https://www.youtube.com/watch?v=4mMHJpSHKJM > god awful nasty smell for days/weeks and can offgas for years is good for air quality ? Everything I've read indicates that any offgassing/odor is gone in 24 hours or less. > In the end of the day people do whatever they want Agreed. To each their own. Closed cell spray foam also works well in conjunction with rockwool.
    - hollerith 2y ago

jordanb 2y ago

I have an interest in metal boats and in the 70s-80s it was common to spray foam these vessels. This pretty much always caused premature end of life due to corrosion. There's a whole class of corrosion in metal structures called Corrosion Under Insulation or CUI. This is a problem for any insulated metal structure, but it is way worse with spray foam because the foam traps moisture very effectively, when it breaks down it becomes acidic, it is difficult to remove for inspection or repair, and it makes hotwork dangerous because it is flammable. When I started seeing wooden houses and roof decks get spray foamed, I could only think that these structures will likely be rotten and useless in 20-30 years. I would only sprayfoam something if the substrate is completely impervious to moisture, like if it was fiberglass or something. Even then you're likely looking forward to a pretty evil concoction under that insulation in a decade or so.

yobbo 2y ago
Some fibreglass boats are still filled with spray-foam, and it has the known effects of eventually causing rot to any wood that might be embedded in the fibreglass. Embedded plywood is much less common nowadays though. (The foam cores in modern fibreglass construction is PVC-based, moisture safe, and can not be sprayed.)

xnx 2y ago

Really? Properly installed closed-cell spray foam seems to have a ton of benefits: Moisture barrier: It blocks water vapor and prevents mold growth by reducing humidity levels in crawl spaces and other areas. Structural strength: It can double the racking load of a home, making it more resistant to severe weather. Air sealing: It protects against drafts, cold spots, and uneven heating. Longevity: It retains its R-value over time and can last for decades if installed correctly. Energy cost savings: It reduces your carbon footprint by consuming less energy. Improved air quality: It doesn't contain harmful micro substances like fiberglass insulation.

lm28469 2y ago
Moisture barrier: it traps the humidity in places you potentially don't want to Structural strength: yeahhhh... no Longevity: not more than anything else, a pain in the ass to replace though Improved air quality: The petrol derivate foam that leaves a god awful nasty smell for days/weeks and can offgas for years is good for air quality ? rock or better sheep wool is much better in that regard In the end of the day people do whatever they want but I'd rather build smaller and spend more on rockwool than have extra space and nasty ass foam all around my house
- xnx 2y ago
  > Moisture barrier: it traps the humidity in places you potentially don't want to Definitely a risk with any type of improperly installed moisture barrier (like ZIP sheathing). > Structural strength: yeahhhh... no It would take me some time to find more formal studies, but there are a lot of videos on YouTube that demonstrate the addeded strength. Here's one: https://www.youtube.com/watch?v=4mMHJpSHKJM https://www.youtube.com/watch?v=4mMHJpSHKJM > god awful nasty smell for days/weeks and can offgas for years is good for air quality ? Everything I've read indicates that any offgassing/odor is gone in 24 hours or less. > In the end of the day people do whatever they want Agreed. To each their own. Closed cell spray foam also works well in conjunction with rockwool.
  - hollerith 2y ago