The term soffit originated from a Latin base word which means “to fix underneath” and a French word which translates to “formed as a ceiling.” Exterior soffits are found beneath the rafter tails of a roof eave. For architectural structures like ceilings, staircases, and archways, the soffit is the horizontal underside. On the other hand, a fascia is the exposed vertical finishing edge at the end of the rafters. It can also be the area where the gutter attaches to the roof. The functions of these roof elements are not just for aesthetics, but also as protection against pests and to provide added ventilation.
A soffit typically has slits or small holes that allow air to circulate. Soffits typically function to assist ventilation in attics. This portion of the roof overhang may attract pests. During inspections, it is necessary to check this part for cracks and rotting. In most cases if rotting occurs the whole roof must be replaced. This layer is also responsible for protecting the attic insulation. Although soffits are traditionally made from materials like wood and aluminum, building owners are now switching to synthetic materials like vinyl and UPVC. Vinyl effectively withstands deterioration caused by heat and moisture, making it the best material for soffits.