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Discussion Starter · #1 ·
Summary: I'm trying to decide the best position for gutters. How far to hang them below the edge of the roof, and how far out from it. Should be simple. Haha! Yeah right. Details below.

I’ve got 8/12 slate roofs. Fascia are angled 90 degrees to the roof slope. Slates overhang fascia by 2″.

I’m trying to choose the best positioning for K-style gutters. I want to protect the gutters from being torn down by snow and ice slides off the (slate) roof. My understanding is that keeping the vertical elevation of the front lip of the gutters 1/2″ below the plane of the roof is how to try and achieve that.

But… it’s not entirely that simple. There’s also a horizontal component of the gutter position to choose, too. That’s the distance, perpendicular to the pull of gravity, between the front lip of the gutter and the edge of the slates. Looking straight down into the gutter from above, that’s the width of the opening down into it, between the edge of the slates and the gutter’s front lip. The maximum possible size of that opening can be varied by how high or low on the fascia, vertically, the gutter is positioned.

The higher up it’s hung, the closer in, horizontally toward the edge of the slates you need to keep the gutter’s front lip to maintain its 1/2″ vertical distance below the roof plane. The lower down you hang it, the further out horizontally from the fascia, you can bring the gutter’s front lip and still maintain its 1/2″ vertical clearance below the roof’s plane. And doing the latter increases the size of the opening down into the gutter.

There must be an optimum combination of horizontal and vertical positions for the gutter. There’s obviously an unambiguous high point, vertically, you can’t and don’t want to exceed. But how low, vertically, is too low to position it?

I need to make my own fascia brackets to hang my gutters from. I can’t find a gutter company that has fascia hangers of their own to use on my angled fascia and trim. They all want to use hangers that will be attached into holes drilled through my roof slates. I want no part of them doing that. The slates are old, brittle, and laid over the roof’s original cedar shakes. Screwing brackets down into them will break many, I’m sure. If snow and ice do catch on the gutters then, that would tear off slates along with them.

From taking measurements, making calibrated drawings, and making my own hangers, if I hang a 6″ gutter on its high end as high up as I can (and out of the way of sliding snow and ice), that will give me an opening width down into the gutter of 2.75″. Then, as I go towards the other end of the gutter, using a downward slope of 1/4″ per 10′ of run, that will be a total drop in elevation of 1″ after 40′. That 1″ drop will let me bring the front lip of the gutter a little further out horizontally from the fascia, if I want, to increase that 2.75″ opening width a bit more, from the starting end.

My basic question is, is a 2.75″ opening big enough, in the first place? Or should I try and adjust things to get it larger?

It seems like I can play with all the variables but I think I need to begin with deciding where on the fascia, vertically, I hang the gutter. Everything else follows from that. Does anyone have any recommendations about that?

Sky Wood Shade Twig Beam


Thank you for any feedback!
 

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Welcome to the Chatroom.

There was a segment on a recent “Ask This Old House” episode that would be worthwhile watching. About 14:50 into this link.

Do you have enough history with the building to know how ice and snow come off it and how much protection the gutters need from being damaged?
 

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Those slates do stick out a fair bit forward.

If your concern is the horizontal projection, I think you could add an extra 1x screwed into the existing one to get it more forward.

In snow / ice country I'd have some concern about the possible weight build up, in a 6" gutter. The one thing I recall from This Old House, way back when, - and hopefully I recall that correctly - also was to keep the front lip of the gutter, below the linear projection of the roof. Which makes sense considering roof raking may be required, at times, depending on ones location. But perhaps not with a slate roof, infrequent snow and sunshine. Have not had a slate roof :)

If it were me, I would do a trial with one section of 5", a 1x, ... garden hose. Maybe even making a few little two foot mockup sections. Couple clamps or some screws. Install one left, middle, right. See how that lines up. There's only so far that measurements and drawings take one ... and sometimes the best inspiration or solutions come trying to put the product up, but instead of struggling solo with a 10 footer ... you get the idea ;)
 

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Discussion Starter · #5 · (Edited)
View attachment 719845

View attachment 719846
The catch with this solution on an angled fascia, as you lower the vertical position of the gutter down the front of the fascia, for your 1/4" per 10' slope downward for the gutter run, that angle the fascia's at makes the gutter's horizontal position beneath the edge of the roof move further back.

Because this isn't already my specialty, I'm not sure how small I should let the width of the opening down into the gutter get, off the ends of the slates. At the beginning of this gutter run, I've got that width figured out to be 2.75" with the gutter mounted up as high on the fascia as I can go while still keeping the front lip of the gutter below the slope line of the roof.

By the time I get to the other end of the run, 40' away, I'll have to have the gutter at that end mounted an inch lower, for its drainage slope. That will also reduce that 2.75" opening down into the gutter I started with at the opposite end. 2.75" seemed minimal to begin with, if I think about needing to get down into the gutter to clean leaves out, etc. Do I really want to let that dimension get any smaller?
 

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The catch with this solution on an angled fascia, as you lower the vertical position of the gutter down the front of the fascia, for your 1/4" per 10' slope downward for the gutter run, that angle the fascia's at makes the gutter's horizontal position beneath the edge of the roof move further back.

Because this isn't already my specialty, I'm not sure how small I should let the width of the opening down into the gutter get, off the ends of the slates. At the beginning of this gutter run, I've got that width figured out to be 2.75" with the gutter mounted up as high on the fascia as I can go while still keeping the front lip of the gutter below the slope line of the roof.

By the time I get to the other end of the run, 40' away, I'll have to have the gutter at that end mounted an inch lower, for its drainage slope. That will also reduce that 2.75" opening down into the gutter I started with at the opposite end. 2.75" seemed minimal to begin with, if I think about needing to get down into the gutter to clean leaves out, etc. Do I really want to let that dimension get any smaller?
Your right, that tight to get in there to clean out a gutter is not good.
Can you drop the gutter mounting down some more on the fascia?
And you need plenty of hangers, maybe every 16" is good. More hangers better the support.
 

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On his forty foot section it would only mean 1" of difference.

Those wedges do look cool, and would help with the visual aesthetic to level them out ... but may be risky when dealing with snow and ice sheets running off, or roof raking, if needed.

Perhaps the solution would be to put a filler strip in the lower part of the board, then wooden shims, then new fascia board over it + gutters.

If length and angle is an obstacle, perhaps use two down spouts instead of one. That's what I plan to do, when I redo our gutters next year. One on each end of a long section, and no more gutter emptying out into another gutter.
 

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Y’all are overthinking this big time. I own a gutter installation company. We use thousands of those wedges a year. I’ve used them successfully in Chicago even. They worked just fine. And you don’t need a quarter inch per 10 foot of slope on a gutter. It will drain with significantly less slope. Maybe OP has a lot of time on his hands and just wants to play with his tablesaw lol.
 
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