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Kris Russell
Posted: Aug 05, 2011 06:58 PM
SPF in existing attic
f i have the roof deck spray foamed with open cell and close up all the vents, do i need to install a fresh air intake in my home? will i have enough air movement through the walls that have batt insulation, and through the doors and windows? thanks
mason
Posted: Aug 05, 2011 09:38 PM
It depends on how tight the house has become after the foam application. 0.35 air exchanges per hour is the sweet spot you are looking for. In most existing houses, there is enough natural air infiltration through the windows, walls, etc. To be sure, you could do a blower door test to see if there is the correct amount of natural ventilation. If not, then you need to add some make up air.
Kris Russell
Posted: Aug 05, 2011 10:29 PM
thanks Mason. Ill do some research on how to do the door blower test so that I am prepared when the time comes.

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