Fascia board is the wood trim on the end of roof rafters. The fascia board mounts onto the end of the exposed roof rafters to protect the edge of the roof from the weather. Fascia board nails onto a roof design, where the rafters extend past the edge of the exterior walls. Not all homes use fascia board because there are other alternatives.
One alternative to fascia board is not allowing the rafters to extend past the exterior wall. This makes the rafters flush with the exterior wall and siding can then run up to the shingles. This home design does not require fascia board on the end of the rafters, but ventilating the roof decreases. A roof with no overhang has more roof vents for better ventilation of the attic.
Drip edge is an aluminum roofing material that mounts to the edge of the plywood roof before installing shingles. The drip edge extends past the end of the rafters, preventing rain water from running down the shingles and onto the face or exterior of the home. Imagine L-shaped aluminum 2 by 2 inches, with a lip extending past the corner; this is the look of drip edge. This alternative material nails to the roof edge all the way around the roof line.
Vinyl siding is a common alternative to fascia board. This type of rafter facing does not rot or wear as quickly as fascia board under the same weather conditions. Vinyl siding easily installs onto the end of the rafters and air vents mount onto the bottom of the vinyl soffit, allowing air to flow through the roof section. The vinyl is an inexpensive alternative to fascia board, which protects the rafters and is as good or better than fascia board.
Placing a gutter system on the end of the rafters with no fascia board is another common alternative. The gutters perform the same purpose of the fascia board and cosmetically covers the end of the rafters so the roof line is not seen. The gutters mount to each rafter end with a long nail or spike that is run through a tube. The gutter system runs along the edge of the roof line and catches water, directing the water to a downspout and away from the house.