I inspected a house today that replaced shingles with metal. The gutter looked too low and just looking down the roof it looked as if the trajectory of fast moving water off the metal roof would overshoot the gutter. So being a nerdy engineer I dug out my hydraulics books and computed the volumetric flow rate for 1/8" and 1/4" water depth and the trajectory running off a 4:12 pitched shingle roof versus a metal roof. Turns out increasing the water depth increased the water flow rate by 158% on the same roofing material and switching from shingles to metal increased the flow rate by 137%. The graphic below is a scaled drawing showing the calculated trajectories.
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If you had a 2 story home, do you think that the water would be thrown far enough away from the foundation, assuming 2% slope, that you could lose the gutters?
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𝓝𝓲𝓬𝓮 𝓰𝓻𝓪𝓹𝓱𝓲𝓬, 𝓡𝓪𝓷𝓭𝔂.
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In my opinion, no. There is a larger trajectory right off the roof plane, but gravity will soon take over and drop the moisture only a foot or two from the foundation, of course depending on the overhang width.
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Lose them if you want.
Gutters are optional, and in northern snow-belt zones, are a hindrance adding to ice damming issues that cause untold damages.
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IMO, going without gutters has far more to do with soil drainage conditions than a few inches of where water lands. I’ve done most of my inspecting in Oregon where the soil basically sucks… heavy clay that holds water for a ridiculous amount of time. Over the last couple years I’ve been inspecting in Hawaii where everything is lava rock and the soil drains at lightening speed. Most of the houses here have no gutters other than strategically placed over entry doors to keep water from running on people’s heads as they enter/exit.
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That’s interesting Randy. I’ve never seen gutters hung that low, but when I do…I am coming for this graphic! 
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Same here in GA. I recently inspected an assisted living 1 story building with very wide eaves, the overhang was near 40". Consequently, no gutters were needed and I think it was a smart design. (it also protected fenestration)
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Many years ago, I was inspecting a vacant house with Gutter Helmets. Gutter Helmet | Never Clean Your Gutters Again
I have always been dismissive of these things but had never actually seen one work in a rain storm. This house had a water hose and sprinkler, so I pulled the hose and sprinkler up on the roof, and started playing with it.
At a drizzle, the gutters diverted the runoff, but at even a moderate spray, the runoff on the roof sheated over the top of the helmet and into the yard. My scorn for these things was vindicated.
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This was from last week… but it’s concrete tiles… (here you go randy! Forgot one) haha
I called it out that it looks like it wouldn’t catch anything during a heavy rainstorm
But this was more due to the tiles overhanging than the gutter height
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Back when I used to frame houses in the Charleston area occasionally one of our notorious afternoon thunderstorms would break out for about a half hour or so. So we would sit it out. But you could see the rain shooting past the gutters on every home. I suppose gutters catch those drizzly rains that last all day but the kind of rains we get…and sometimes they’re every afternoon…it’s not catching much.
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4" gutters are typical in my area from the builders. I replaced mine with 6"
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Same here, six inch gutters with 4 inch downspouts. I also had gutter guards installed, no more climbing ladders on hills to clean leaves out of my gutters.
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Which type do you get?
Here is what i had put on
Leaf Terminator - Gutter Topper
That’s why i did it, Walk out basement, so two story in the rear where all the trees are and sloping downward to a creek. I’m getting to old for that crap.
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Nice looking
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How are they connected? I don’t see screws at the outer edge
Their screwed onto the gutter, look closer, you’ll see two stainless screws on the upper outer edge. My roofer installed them, they’re heavy duty and rigid so they didn’t need to install screws every few inches. I think they told me 25 year warranty on them, which is longer than I plan on living here.
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I see them now, i was looking for the same color screws, couldn’t tell what those were.
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