Gutter Installation: Costs, Sizes, Materials

Aluminum is the most popular gutter material. It’s light and doesn’t rust, but it can dent from hail or falling branches. Guides put its life at about 20 to 40 years.

Vinyl costs the least and is easy to put up, but it tends to crack and warp over time and doesn’t last as long as metal. In wildfire-prone areas, a home inspectors’ association advises metal gutters and downspouts over vinyl.

Galvanized steel is stronger than aluminum and stands up to impact better, but it’s heavier and can rust if it isn’t maintained. Guides put its life at about 20 years. Copper and zinc cost the most. Neither one rusts, both weather to a natural patina, and both can last 50 years or more.

Gutters also come in different profiles, or styles. K-style, with a flat back and a front shaped like crown molding, is the most common on houses today. Half-round gutters are an open half circle, often chosen for older and traditional homes, and they pair with round downspouts. A K-style gutter holds more than twice the water of a half-round of the same width, and it usually costs less.

Most houses have 5-inch K-style gutters, and that size handles the runoff from most average roofs. A 6-inch gutter carries more water. Guides suggest it for large roofs, steep roofs, slick roofing like slate, and places that get frequent heavy rain, since steeper roofs shed water faster.

The usual sizing method starts with the roof area that drains into each gutter run. That area is multiplied by a factor for roof pitch, from 1 for a flat or low roof up to 1.3 for a roof of 12 in 12 or steeper, and by the local rainfall intensity for a heavy five-minute storm, which NOAA publishes by location. The result is checked against a sizing chart. In one common chart, a 5-inch K-style gutter handles up to 5,520 square feet and a 6-inch up to 7,960. Half-round gutters handle less: about 2,500 at 5 inches and 3,840 at 6 inches.

Downspouts have to keep up with the gutter. A 2-by-3-inch downspout drains about 600 square feet of roof, and a 3-by-4-inch downspout about 1,200. One guide pairs 5-inch gutters with 2-by-3-inch downspouts and 6-inch gutters with 3-by-4-inch ones. Guides suggest a downspout every 20 to 50 feet of gutter, closer together where heavy rain is common.

Before recommending a size, a company should look at your roof area, pitch and number of downspouts. The extra cost of 6-inch gutters is in the table below.

On a replacement, the crew first takes down the old gutters and downspouts and hauls them away. Some quotes include removal and disposal and some list them separately, so check.

With the old gutters off, it’s the right time to check the fascia board behind them. Rotted fascia should be replaced before the new gutters go up, because hangers only hold as well as the wood they’re fastened to. A house that never had gutters may need fascia work first, too.

The new gutters hang on hangers spaced along each run, with extra hangers where snow and ice are heavy. One guide recommends hidden hangers that screw into the fascia, since the older spike-and-ferrule kind can pull out over time. Each run gets a slight slope toward its downspout, commonly about a quarter inch to a half inch over 10 feet, so water doesn’t sit in the trough.

Downspouts go where each run can drain, with elbows and an extension or splash block to carry water at least 4 feet from the foundation. Corners, end caps and outlets are sealed. Before the crew leaves, ask them to run water through the gutters so you can see every run drain.

Ask for a written quote that lists each part on its own line: feet of gutter, size and style, number and size of downspouts, removal and haul-away, and any fascia repair. Quotes laid out the same way are easy to compare.

Ask how thick the metal is. Aluminum gutters come in different thicknesses, and one cost guide recommends .032-inch over the lighter .025-inch for strength. Steel is sold by gauge, where a lower number means thicker metal.

Ask what hangers they use and how far apart they’ll be spaced, what size downspouts they plan, and whether the gutters will be seamless or sectional. Ask what the warranty covers, for materials and for the work, and get the terms in writing.

Ask for proof of liability insurance before work starts. If your state licenses contractors, you can also look the company up in the state’s database. SirGutters lists companies from their own websites and doesn’t check licenses or insurance.