Okay to open vapor/air barrier, when the heat is on and temps are dropping? – GreenBuildingAdvisor

Unfortunately, I am needing to dive back into a couple of wall assemblies.  Slab heat is on, set at 65 degrees, and needs to be maintained now through the winter.   Temps are below freezing in the morning and hard freeze up is imminent within the next few weeks.  CZ7.

How much moisture am I letting in when I cut open the vapor barrier for a day to do some work before sealing it up?  Is there a timeframe I should abide by or any other guidance you might have? 

Thank you, Ian