Huber Zip R-Sheathing with open cell insulation
I’m involved on a project where the insulation contractor would like to use closed cell spray foam insulation in our wall cavity in order to mitigate the risk of condensation. We were originally planning on using open cell foam. Climate zone is 5/4 Marine, project is on the coast.
The wall assembly is ;
– 1-1/2″ Huber Zip R-Sheathing
– 2×6 stud wall
– 5-1/2″ open cell spray foam insulation
– 1/2″ drywall
1. Are we at risk of condensation in our wall if we use the open cell insulation?
2. Would adding 1″ of closed cell spray foam mitigate the risk? We would then use 4-1/2″ of open cell to fill the cavity.
3. Is the ratio of rigid insulation to open cell insulation in the cavity acceptable?
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