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habbi
 
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Default ventilating closed in rafters

What is the proper way to ventilate closed in rafters. I am building a new
house and the "great room" has cathedral ceilings made with 16" I joists on
24" centers at a 14/12 pitch. It is sheathed with 6" boards then tar paper
and asphalt shingles. The boards are fairly green being sawn this past
summer. Anyway I was told to use styrofoam truevents top to bottom (~18
feet) so air can enter the bottom and exit the ridge vent. As I see it, this
will not draw moisture out of the space with insulation. Should I space each
4' true vent from each other by an inch or so? Should I cut little holes
periodically. I am just thinking that if moisture finds it way through the
vapour barrier and into the insulation it should have a way of getting into
the space provided by the true vents. Also the true vents I have seen are
only 12" wide and the rafters are on 24" centers. Should I put 2 side by
side or is 1 enough. Thanks for any opinions.