Have you ever driven past a restaurant and become hungry because the smell of fried chicken is in the air? Well, that smell from the restaurant is likely coming from the roof. Ventilation and exhaust for the building are typically provided by HVAC equipment on the roof. That exhaust vent for the kitchen is probably providing the source of that delicious smell. However, that smell comes with some dangers for your roof. Many roofing membranes do not like animal fats, oils, or greases; unfortunately, that fried chicken comes with many greases. There are grease traps that catch the fats and oils, but often, they are not well-maintained. When the grease trap is full or damaged (or non-existent), the fats and oils have nowhere to go but on the roof. When that happens, the fats and oils may wear down the membrane. Regular cleaning and maintenance of exhaust vents are important to preserve the life of your roof.