I am posting this here, because of what I learned here on another thread. I am experiencing heavy condensation on attic ducts and have decided I either have to reinsulate the ducts or, as has been suggested, foam the attic roof. I either have to raise the skin temp of the ducts or lower the attic temp & humidity to stop the condensation.
The foam contractor wants to foam the rafters and seal all the penetrations, including power vent and soffit vents. It is 1900 sq feet and it is very hot and humid here at the coast in SC. I have always believed in attic ventilation, but here you just bring in more hot humid air.
Does anyone have any experience with this process or foam type?
Wouldn't we need to ventilate this area some how?
I am concerned about other potential ramifications, such as roof sheathing or shingle problems. There are also two types of foams: Icynene, which is water based and open cell and polyurethane, which I believe is closed cell, but I have concerns about the chemical smell and toxicity if there should be a fire.
Contractor claims attic will stabilize at 4 or 5 degrees above the second floor temp.
Wouldn't this affect manual J calculations for the rooms below?
Don't mean to offend anyone, so if you know of a better forum on which to post this question, please let me know. This forum has many responders who promptly reply and try to help. Thanks.