# Foam sprayed attics



## Shockdoc (Mar 4, 2010)

I heard they stay much cooler than the conventional attic. Is this true?


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## sarness (Sep 14, 2010)

I think I would seal, can still have air movement.

As for temperature, I've noticed about a 10 degree difference between room temp and attic temp on a hot sunny day.

They also say it will shorten shingle by 5-8 years.


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## McClary’s Electrical (Feb 21, 2009)

The foam spray would not take place until after your rough in inspection. Therefore, you're still gonna have to draftstop your own penetrations


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## Shawn23 (Jan 5, 2011)

Shockdoc said:


> I heard they stay much cooler than the conventional attic. Is this true?


 
This is very true! I have noticed that when working in an attic that is foamed the temp is usuall not more than 5 to 10 degrees warmer than in the house.


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## Shawn23 (Jan 5, 2011)

mcclary's electrical said:


> The foam spray would not take place until after your rough in inspection. Therefore, you're still gonna have to draftstop your own penetrations


 
This is a good point but if it shows on the plans that the whole house is getting foamed it seems like a waste.


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## kaboler (Dec 1, 2010)

A spray foamed attic? There's 20,000 the homeowner will never see again hahahaha. Cellulose!!!

As for foaming the holes, I would if you couldn't see foam going into the top plate where the holes exit (or whatever you'd call it). There's no guarantee that the spray foam people did a good job, because there's no good way of checking.

Spray foam is flammable. Even cured. It's dangerous to sprayfoam a whole house, but hey, Holmes on Homes does it.


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## Shawn23 (Jan 5, 2011)

I think my point is that if the whole purpose of foaming our holes when we are done is to stop the air from the attic from feeding a fire in the living space then why would it be needed if the attic is air tight from the foam there is no air to feed a fire?


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## kaboler (Dec 1, 2010)

Maybe in Florida, but in Canada, we fill em to keep air from slowly cycling through the holes. In some houses, let's say you have a 1000 square foot wall. It's basically a big big sail. And if you somehow design your home to pull air in through the soffit and then a homeowner opens a door, that's a lot of pressure, and wind will come through those wire holes. In Canada, you can feel, in a house not properly done, wind coming through receptacles and switches.

So for us, it's a vapor barrier, because you pierce the vapor barrier between the plates when you drill your hole, and now you have to repair the cut.

In Florida, maybe you want to stop the hot air from getting inside. I dunno. Don't think it's about fire code.


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## Shawn23 (Jan 5, 2011)

kaboler said:


> Maybe in Florida, but in Canada, we fill em to keep air from slowly cycling through the holes. In some houses, let's say you have a 1000 square foot wall. It's basically a big big sail. And if you somehow design your home to pull air in through the soffit and then a homeowner opens a door, that's a lot of pressure, and wind will come through those wire holes. In Canada, you can feel, in a house not properly done, wind coming through receptacles and switches.
> 
> So for us, it's a vapor barrier, because you pierce the vapor barrier between the plates when you drill your hole, and now you have to repair the cut.
> 
> In Florida, maybe you want to stop the hot air from getting inside. I dunno. Don't think it's about fire code.


 
I have always thought it to be a fire code but now that you bring up this possibility I will call our local inspector to confirm the reason for and reference to refer to.

Great discussion guys, lots of good input.


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## McClary’s Electrical (Feb 21, 2009)

Shawn23 said:


> I have always thought it to be a fire code but now that you bring up this possibility I will call our local inspector to confirm the reason for and reference to refer to.
> 
> Great discussion guys, lots of good input.


 

It is about draft stopping, but that in turn is also about firestopping. To add to the other post about the wall and sail, now light that wall on fire. In test burns in the NFPA labs, the holes that not draft stopped "draft" naturally. They become little blow torches. Every single hole. Concentrated fire. Draft stop that hole, and the fire spreads less rapidly.


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## Shawn23 (Jan 5, 2011)

mcclary's electrical said:


> It is about draft stopping, but that in turn is also about firestopping. To add to the other post about the wall and sail, now light that wall on fire. In test burns in the NFPA labs, the holes that not draft stopped "draft" naturally. They become little blow torches. Every single hole. Concentrated fire. Draft stop that hole, and the fire spreads less rapidly.


 
Good point and it makes since. I love a code that is practicle.


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