How to Install Gutters. Gutters (or eavestroughs) aren't just a "nice to have" accessory. Gutters perform an important role in helping keep water out of your basement. Properly installed gutters will catch water coming off your roof and channel it well away from your home's foundation so it can't work it's way in and create a musty smelling (or, even worse, moldy) lower level. While installing long seamless gutters or highly decorative gutters (like copper) is best left to the professionals, sectional gutters (usually made of vinyl or aluminum) can be installed by a handy homeowner (and hopefully a friend or two).
Look at the outside of your home and determine how you would like the gutters to channel the water. You want the gutter to catch the water as it comes off the roof and channel it to an area where it will drain away from your home.
Measure along the edges of your roof. Gutters often come in 10-foot sections, so this will determine how many sections of gutter you need. Add 10 percent to your measurements for wastage (you will need to cut some pieces to fit).
Combine the roof measurement with your gutter layout plan to calculate the number of other gutter components you will need (corners, elbows, end pieces, drop outlets). You will also need mounting brackets for every 24 to 30 inches of run.
Installing Your Gutters
Begin at the end of your roof away from the downspout location and measure down 1/2 inch from the edge of your roof and mark it. Move to the downspout end and again measure and mark down 1/2 inch from the roof edge. Use a string level to be sure these marks are level with each other and adjust them if necessary.
Calculate the slope you will need so the water in your gutters will flow towards the downspout. (Gutters should slope down 1/16 inch for every foot of run or 5/8 inch for every 10 feet.) Measure down this distance from the first mark at the downspout end.
Snap a chalk line from the lower mark at the downspout end to the single mark at the far end. This chalk line will be your reference line for installing your gutters.
Install the components of your gutter system--drop outlets (at the downspout end), corners and mounting brackets. The job is easier if you use a power drill with a screwdriver bit and rust resistant screws.
Working from your ladder, install individual sections of gutter into the mounting brackets and join the sections with gutter connectors.
Use a hacksaw to cut gutter sections to fit when necessary.
Run a bead of silicon caulk between the gutter sections to prevent water leaking through the seams.
Install an elbow at the bottom of the drop outlet, then measure, cut and install the downspout to the base of the drop outlet.
Use mounting brackets to firmly attach the downspout to the side of your house.