Fascia boards are installed onto rafter ends, or “tails”, as part of the exterior trim after a house is completely framed. Fascia boards, soffit material, frieze boards, molds, and rafter tails are all components of an assembly that forms the eave of a wood frame house. Wood fascia is easy to install, though there are several techniques used to ensure that the fascia goes on straight and true. Gather the necessary materials and follow these simple steps to install wood fascia like a master carpenter.
Step 1 - Trim Uneven Rafter Tails
The first step is to make sure that the ends of the rafter tails are aligned in the same plane. Drive a nail halfway into the top edge of the plumb (vertical) cut of the rafter tail at one end of the eave. Hook a chalk line onto the nail, stretch it all the way to the rafter tail at the opposite end, align it with the plumb cut, and snap the line. Using a circular saw, cut back any rafter tails that project beyond this line. Tie a string line to the same nail at the end rafter and to another nail placed in the same location at the opposite end rafter. This will show any places where the rafter tails fall short of the plane.
Step 2 - Install the Lookout Blocks
Install a 2x4 nailer flat onto the exterior wall surface so that the bottom edge is level with the horizontal cut of the rafter tail. Measure horizontally from the nailer to the string line and cut a “lookout” block for each rafter tail. Install each block flat against the rafter tail and perpendicular to the nailer. The lookout blocks are used as the structural frame for both the soffit and the fascia. If the upper corner of the lookout block penetrates the roof plane, it will have to be chamfered. The fascia will be nailed into the butt end of the lookout blocks, and so should not have any bows in it where the rafter tails come up short.
Step 3 - Cut Fascia Boards
Adjust the circular saw to 45 degrees for a beveled cut. Fascia boards mitered at each end will provide a stronger joint than a butt joint and will better hide unsightly gaps. Use a measuring square to make sure each cut is square, and then measure and cut each fascia board to the proper length so that every joint falls on a lookout block.
Step 4 - Install the Fascia Boards
Next, install the fascia boards onto the eave. Make the top edge of the fascia even with the top corner of the plumb cut and nail it into the butt end of every lookout block with galvanized finishing nails. If the rafter tails have uneven heights, the fascia boards will be installed with a side bend, also known as a “crook” or a “crown.” If necessary, either by yourself or with some help, apply pressure in the opposite direction of the bend on the board’s free end as you nail into each lookout block. Sight along the top edge of the fascia as you install each board to make sure the fascia is straight along the entire eave.