How to Install a Seamless Aluminum Gutter to the Fascia of a House

Position a ladder at either end of the roof line and climb onto it with a tape measure. Measure the length of the roof in feet and divide the number by 10. Multiply the resulting number by 1/4 to determine how many inches to slope the gutter downward. For example, if the roof is 20 feet long, divide by 10 to arrive at 2. Multiply 2 by 1/4 to arrive at a 1/2-inch slope.

Hold the end of a chalk snap line at the top edge of the left side of the roof and ask the other person to hold the other end at the right side. Move the right side down by the slope you determined and snap the line on the front of the fascia.

Measure 6 inches from either end of the aluminum gutter and draw a pencil mark for the mounting brackets. Draw additional marks between them spaced at 18-to-24-inch intervals. Insert a bracket into the top of the gutter so it spans the top of the gutter opening and the ends snap under the top lips. Insert additional brackets at every pencil line.

Hold the aluminum gutter up to the roof, aligning it on the chalk line. Insert a 1-inch-long wood screw through the screw hole in each bracket and secure it fully to the fascia using a power drill.

Insert a 2-to-3-inch-diameter hole bit into a hole saw and drill a hole in the bottom of the aluminum gutter end that is lower. Apply a bead of silicone caulk around the downspout outlet and drop it in from above the gutter. Insert two sheet metal screws into the top of the outlet using a power drill.

Insert the downspout into the bottom of the outlet under the aluminum gutter. Mount aluminum gutter brackets to the side of the wall using 1-inch long screws and snap the downspout into the brackets to hold them in place.

Apply a 1/4-inch strip of silicone caulk to the inside edge of an aluminum gutter cap and press it into the opposite end of the gutter.