KEN'S ROOFING SUPPLIES LTD.

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[Frequently Asked Roofing Questions]

Q. How many vents do I need in my roof?
A. One sq. ft. of net free vent area for every 300 sq. ft. of insulated attic. AF-50 vents are a net free vent area of 50 sq. inches, so 3 of those will make one square foot. Shilco style metal vents have only 20 inches of net free area, so it takes far more.

Q. Do I have to use felt?
A. Yes, most manufacturers require the use of felt for warranty purposes. It is not necessary to use #30 felt as ice dam protection in this area. #15 felt is sufficient according to the BC Building Code.

Q. What width of valleys should I use?
A. We consider the standard size to be an 18" valley, however, roofing inspectors are requiring 24" valleys be used in some areas.