Sloped ceiling insulation
IRFL
| Posted in Energy Efficiency and Durability on
In climate zone 5 we have renovation of a cape home and a suggested sloped insulated roof design as following:
Soffit to ridge ventilation with baffles the entire way. Blown in fiberglass insulation in 2×8 rafters 16 oc. Underside of rafters covered with 1.5″ Thermax under the entire roof.
Question: Where is my dew point in this assembly and are their any concerns with this type of air barrier and insulation design?
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Replies
Flemming,
If you pay attention to airtightness, you are all set. You don't have to calculate the dew point in your assembly, because it is a vented assembly. As long as you don't have any significant air leaks, there won't be any moisture to worry about.
how are you doing your continuous soffit to ridge ventilation? IE what products and how big is your air gap between vent channels and roof?
I will use the AccuVent Cathedral ceiling vent baffles. They work great to with closed cell foam insulation if venting is to be maintained. http://www.brentwoodindustries.com/spg/building-products/