A good roofing system is all in the detail. Insure that things like, your roofer is using 30 Lb. felt 44 inches wide at eaves line and also in all valleys. The rest of the roofing field is covered with 15 Lb felt. Your ventilation meets manufacturer's specification and B.C. building code. Your Roofer is in good standing with WCB, carries liability insurance, remember roofing is DANGEROUS.

I Will get into detail about different roofing systems at a later date.