Proper sizing is key
Gutter installation is not rocket science, but it is something that does require some basic engineering. A single run along the lower edge of a shed roof with a corner downspout is about as simple as it gets. Homes with multiple roof lines, various degrees of pitch and multiple gables add a level of complexity that requires a plan. The key factor in developing this plan is to scale the system based on the square footage being served and factoring in your potential for heavy down pours. The downpour factor is based on weather data and varies by region. A 5 minute “burst” in Seattle is rated at only 2.1 inches per hour, while the same “burst” in Atlanta is 8.3 inches per hour. A 5” K style gutter is rated to move about 5500 sq feet, while a 6” version can handle over 7500 sq feet. A Seattle roofer will install different gutters than a roofer in Atlanta. Knowing what Mother Nature can throw at you will allow you to plan accordingly.
Pitch and downspouts
Gutters make up half of the roof’s collection system. The downspouts make up the rest. Sizing here also can make the system perform properly. A basic 2 x 3 inch rectangular downspout is rated for about 600 sq feet, while a 3 x 4 inch spout can handle 1200 sq feet. One way to squeeze out some more performance of the system is to increase the slope of the gutter. Normal installs are typical at about ¼” of slope in 10 feet, with down spouts needed about every 40 lineal feet. As an example: if you have a 50 foot run, a downspout should be installed at both ends. For proper flow the pitch should be centered from the middle out to the spouts. Steeper pitch of the gutter allows the water to flow more freely and it helps with keeping the gutters free of debris. Extreme pitch however may look a bit wacky from the street and add complications in its install along the fascia.
Gutter guards or open?
This is the big question many face when it comes to an install. Do I need one? Do they work? Is it worth the extra money? Many gutter companies will insist that you need these and therefore try to milk more money out of you. This is where you need to consider your local environment, maintenance schedule and DIY ability. If your home is located in a forest that sees leaf or needle drop, you are at more risk for needing a gutter guard system. Gutter location will also dictate their need. My home is in an area where pine needles are common.
When I installed gutters on my own home I had the seamless company install basic open gutters on 2 of my three eaves. One eave is over 30 feet in the air and drips along a seldom-traveled area of the yard. That part of the home is also on pier footings so my concern for water infiltration was minimal. Clearing the gutter there would be a complex and risky process. Where my gutters are installed are along the driveway side and the deck side. The deck side is more prone to needle drop, and catches more due to the roof size and prevailing winds but having the deck there makes clean out a breeze, a simple step ladder and a few minute every other year and I’m good to go. The opposite side is a 2nd story run but is pretty needle free.
Your choice to install guards should be based on you local situation, and despite the claims many will still require some periodic cleaning. Some designs make this process far worse than an open top system…so the benefit can be nonexistent.