You must consider your personal capabilities, as well as the cost and convenience. The cost of professional gutter installation is very affordable – especially compared to the cost of injuries that can result from falls from roofs or ladders. But if you decide to install your own gutters, be sure to use protective devices such as harnesses, tie-ins, and ropes. Consult OSHA for information on safety during gutter installation.
While installing long seamless gutters is best left to the professionals, sectional gutters can be installed by a handy homeowner with the assistance of one or two helpers. Following are instructions that will get you started.
Look at the outside of your home and develop a gutter layout plan to decide how you would like the gutters to channel water to drain away from your home. Measure along the edges of your roof to determine how many sections of gutter you need. Gutters generally come in 8 to 10-foot sections. Combine the roof measurement with your gutter layout plan to calculate the number of feet of gutter and accessories you will need. (See diagram below for components list.) Tip: You will need mounting brackets for every 24 to 30 inches of gutter you run.
Calculate the slope you will need so the water in your gutters will flow towards the downspouts. Gutters should slope down 1/4 inch for every 5 feet of gutter that you install. Mark the start and end points of the slope of each gutter run. from high to low point, on your fascia board. Snap a chalk line as your reference line for installing your gutters.
If using external brackets, install the brackets on your fascia, then mount the individual sections of gutter onto the mounting brackets. If you are using internal mounting brackets, install them into the gutter first, then attach the gutter pieces to the fascia using the internal brackets. Join the sections with gutter connectors. Run a bead of silicon caulk between the gutter sections to prevent water leaking through the seams.
Carefully determine where your downspouts will fall, then cut a hole in the gutter bottom at each point you will install a downspout, before lifting the gutter up to the roof edge. Re-check the position of the downspout hole for alignment. Install an elbow at the bottom of this gutter outlet, then measure, cut and install the downspout. Use mounting brackets to firmly attach each downspout to the side of your house. Depending on the size and configuration of your roof and size of your gutters, you will need downspouts at least every 30 feet.
Your local hardware retailer who sells the gutters and accessories, should provide manufacturers instructions with the products. Below is a diagram of a guttering system along with a glossary of accessories you will need to install your own gutters.