Q: Why is ventilation so important? A: Ventilation is a crucial factor in the life of a roofing shingle. Heat build-up in the hot summer months, as well as the cold weather of winter will accelerate the aging process of your asphalt roofing shingles. Proper air circulation, regardless of the weather outside, will greatly reduce the chances of leaking, blistering, distortion, curling, rotting of wood structure, wet insulation and many other potential problems. It is also important to note that adequate ventilation is required to validate the shingles manufacturer warranty. In Canada for example, minimum requirements prescribed in the National Building Code must be respected. In all cases, the most stringent applicable building codes must be followed.