# Air exchange in SPF sealed attic?



## Suzanne99 (Jul 17, 2015)

What is the best way to get air continual exchange in an attic that has been insulated with Icynene spray foam and sealed tight? I'm worried about potential leaks from gas pipes building up over time, but SPF sealed attics cannot be vented to the outside.


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## Windows on Wash (Aug 30, 2011)

If the roof plane is insulated, the attic is effectively part of the condition space and should be conditioned via HVAC.


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## Suzanne99 (Jul 17, 2015)

*Air exchange in sealed attic?*

True that it's part of the conditioned space of the house. What I'm concerned about is venting so any potential gas leaks can escape. But installing a vent to the outside would defeat the purpose of the sealed attic. I was hoping there was some way to mitigate the danger. I'm leaning toward using conventional insulation instead (radiant barrier under the roof and blown-in on the floor of the attic). Kinda wish I'd just used all electric now.


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## Windows on Wash (Aug 30, 2011)

You shouldn't have a gas leak regardless and I would hazard a guess that 99% of them are as a result of improper installation at the time of installation. If you are concerned, have the system tested by a certified technician.


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## beenthere (Oct 11, 2008)

Sealed insulated attics are conditioned by the homes central system. Venting them to the outside defeats the purpose of sealing them.

Venting it to the outside, wouldn't make you any safer if you had a gas leak.


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## Suzanne99 (Jul 17, 2015)

*Air exchange in sealed attic?*

If the gas leak had a vent to escape through, wouldn't that mitigate the chances of a build-up and explosion? I'm very interested to know why not. That may make the difference in my decision. Thanks!


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## beenthere (Oct 11, 2008)

Suzanne99 said:


> If the gas leak had a vent to escape through, wouldn't that mitigate the chances of a build-up and explosion? I'm very interested to know why not. That may make the difference in my decision. Thanks!


Just means that the sides of your house would be on fire as well as the attic.

Gas needs air to burn, venting the attic will supply air for it to burn better then in a sealed attic.


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## Windows on Wash (Aug 30, 2011)

In this case, dilution is not the solution.

You should not be preparing for a gas leak by vented a sealed space. Plenty of homes have combustion appliances (gas fed of course) inside the conditioned spaces without issue. 

If you are concerned about the HVAC system and a gas leak, have it checked by a certified technician. Should be part of the standard HVAC multi-point check that most companies offer anyway.


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## Suzanne99 (Jul 17, 2015)

Ok, thanks for all the replies. I guess if I'm that worried about it I should just go with a radiant barrier with vents in the soffits and roof, and blow in insulation or use a closed cell SPF on the attic floor. I have a ton of can lights, wiring, and plumbing up there so SPF might be tricky.


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## beenthere (Oct 11, 2008)

What are you going to do about venting the occupied/living area of your house. It can build up gas. Are you going to have vents running to the outside.

You are worried about something that is not an issue.


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## Suzanne99 (Jul 17, 2015)

The interior of the house will have an HVAC system that exchanges the air, plus the doors will be opened nearly every day, at least for a few minutes. The attic doesn't have that so toxic air (and potentially gas) can build up, which is a known problem. I don't think I could afford to run air conditioning in the entire attic since it's such a large house. It's basically a trade-off between the best insulation energy-wise or the conventional types that are somewhat safer. I really appreciate the conversation going back and forth, every data point helps. (Can you tell I'm an engineer?)


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## beenthere (Oct 11, 2008)

The attic only needs a single supply and return. It doesn't need to be conditioned to complete human comfort level.

Your not going to be opening and closing your doors in the middle of the night while you sleep.


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