i am in middle of building an addition (lean-to) on old house, basically extending roofline over to bedrock. For slope reasons(mountain) and snow load, the roof/ceiling are one section, 4" thick, heavily braced every 2nd truss. I had to sheet and poly the roof because of weather, it is raining for days. I have tin for the roof.
Now that I go to finish with insulation and vapour barrier on ceiling; do I need to remove the poly that was placed on roof over sheeting? Can I put tar paper over this poly and install tin? Will there be a moisture loss between the poly and the sheeting? Or should the tin go straight on the tar paper? I am venting on the low end of roof in-between each section. I have been told that there will be moisture loss that will ruin the roof sheeting.
thanks
Guest User
2009-10-16 22:38:48.000000
"Moisture loss" ... not sure I understand that.
As long as you have excellent ventilation in the attic (intake and exhaust) you should be okay with the non breathable underlayment.