Seamless Gutter Installation in Kent, WA
Aluminum gutters formed on site to the length of each eave, so the only joints on the house are the corners and the outlets.
What Seamless Means
Seamless gutters are roll-formed on site from one coil of aluminum, cut to the length of each roof edge, so the only joints are corners and outlets. In Kent, 5-inch K-style aluminum installed runs about $6 to $13 per foot and 6-inch about $8 to $15.
Sectional gutters come in ten-foot lengths from the hardware store and are joined with slip connectors and sealant. Each joint is a place for water to find its way out, and the sealant lasts a few years before it needs redoing. A seamless gutter skips all of that. The installer brings a roll-forming machine on the truck, feeds in a coil of pre-painted aluminum, and runs out a single piece as long as the eave, forty or sixty feet if that is what the roof measures. The seams left are the mitered corners and the drop outlets for the downspouts, and those are riveted and sealed once.
Aluminum coil comes in two common thicknesses, .027 and .032 inch. The heavier gauge holds its shape better under a ladder and under a winter's worth of wet fir needles, and the price difference across a whole house is small. Ask which one is being quoted.
Five-Inch or Six-Inch for a Kent Roof
Both are K-style, the flat-backed profile with the shaped front that fastens straight to the fascia. The difference is capacity. A 5-inch K-style carries about 1.2 gallons per linear foot; a 6-inch carries about 2, roughly two-thirds more, and it pairs with a 3-by-4-inch downspout instead of the standard 2-by-3. The larger downspout matters as much as the gutter. The outlet is what clogs first when a maple lets go, and the bigger opening passes leaves that would jam the small one.
For a single-story house with a moderate pitch and a downspout every thirty feet or so, 5-inch is the standard and it works. Six-inch earns its extra dollar or two a foot on steep roofs, where rain reaches the eave fast; on long runs that drain to one downspout; and on any roof under big trees, where the extra width buys time between cleanings. November averages 6.31 inches at Sea-Tac and a strong storm can drop an inch in a day, so a contractor who measures the roof area feeding each run and sizes to it is doing the job properly.
Half-round, if the house calls for it
Half-round gutters hang from brackets rather than fastening to the fascia and suit an older or craftsman-style house. At the same width they hold less, about 0.7 to 1 gallon per foot in 5-inch, so a half-round system for a Kent roof usually goes to 6-inch to match what 5-inch K-style would carry.
What Happens on Install Day
- Measure and mark the pitch. Each run is set to fall toward its downspout, about a quarter inch every ten feet. Too flat and it holds water; too steep and it reads crooked from the street.
- Take down the old system and look at the fascia. Soft or stained wood gets replaced before anything new goes up. This is the most common change to a quote and the one worth paying for.
- Form the runs on site, cut to length, and hang them on hidden hangers screwed into the rafter tails, typically every 24 inches and closer on long runs.
- Miter and seal the corners, set the outlets, and run downspouts to where the water is supposed to go; see downspouts and drainage.
- Water-test with a hose and check every corner and outlet before the truck leaves.
A typical house is a one-day job for a two-person crew. Two stories, a complicated roofline, or fascia repair can push it to two.
What Seamless Costs Here
Installed 5-inch aluminum runs about $6 to $13 per foot in the Kent area and 6-inch about $8 to $15, with a typical house landing between $1,500 and $4,000 for the whole system. Corners, second-story work, downspout count, and fascia repair move the number. The cost guide has the full table and what to look for on a bid.