A roofing system is made up of underlayment, flashing, venting, and roofing materials.
Underlayment: This is the layer under your shingles that provides a water-resistant or waterproof barrier. It is made of asphalt-saturated felt, synthetic materials, or rubberized asphalt.
Flashing: Flashing is a thin layer of waterproof material that prevents water leaking into your home by directing rain water down the roof to the gutter system.
Venting: Roof ventilation helps airflow through a system of intake and exhaust. Proper roofing ventilation will extend the life of your roof and reduce energy costs.