The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck.
Vented roof underlayment.
Cedar breather ventilated underlayment cedar breather protects the beauty and life of wood roofing by providing a space for continuous airflow between the solid roof deck and shingles or shakes.
The key goal is keeping the underlayment watertight.
Most synthetic underlayments are approved for roofs as low sloped as 3 12 provided that the material is overlapped by about 50.
On this roof installation as on much of his project the owner did much of the work himself in order to learn about the new high performance products.
In a cold climate the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned.
Enhnaced warranties from shingle manufacturers usually consists of using four 4 of their products.
To protect against wind driven rain lap the underlayment under the rake edge.
In fact installing this vented underlayment is straighforward enough for first time installers.
The fact that a self adhesive underlayment system is recommended says it all and magnifies the need for a proper roof ventilation system.
For optimum performance use cedar breather with rapid ridge 7 ridge vent.
Roofing materials vent underlayment and other components owens corning roofing.