- Measure around your home on the edge of roof peaks. All level edges of your roof will have gutters attached to them. Take this measurement and purchase 8 percent to 12 percent more feet of gutters as you may mess up on gutter cuts. Also purchase all downspout attachments, corner gutter pieces and 90-degree ground gutter elbows for each roof edge.
- Most roofs have an overhang with a 4-to-8-inch board for an edge; this works perfectly for attaching your gutters. If the roof is flush with the vinyl siding, the same rules apply for connecting your gutters to the vinyl siding. Put a ladder up on each end of the edge of the roof. Measure 0.5 inches down on the high end of the gutter; you will need a slope on the downspout end. The gutter slope needs to drop 1/16 of an inch for every foot of gutter. Figure the drop for this gutter edge length and mark the lower point at the other downspout end of the gutter. Use a color chalk string to mark the slope onto which the gutters need to be mounted.
- Screw in the gutter mounting brackets over the gutter pieces along the marked slope line on the edge of your house. Fit each piece of gutter together, and apply outdoor silicon on the edge of the fitting gutter to seal each piece. Mount them starting at the high end first. Cut gutter pieces with a steel cutoff saw or a handheld hacksaw. At the downspout end, apply outdoor silicon around the lip of the top of the downspout, place it through the downspout hole in the edge gutter, and screw it into place. Screw mounting brackets into the vinyl siding over the downspout gutter. Fit the 90-degree angle ground downspout gutter on the end of the downspout. Place another piece of gutter on the 90-degree piece if you want to get the water farther from the house. You can also put a splash pan under the downspout exit.
