Roofs, Snow and Gutters
I believe that I understand the following:
– That in snowy climates, let’s say CZ 6 and above– you don’t want to install gutters because snow shedding off the roof will just knock them off.
We will be building a new home and installing a steep, 12/12 pitched shingled roof in CZ 6 on the outskirts of the Tetons near Alpine Wyoming. It can snow a good bit, but nothing insane like Tahoe or Alaska.
Curious if this roof shape, location and configuration would support the idea to go without gutters.
If so, is the idea just to have a great french drain? Of course we are planning to install a solid french drain system. And perhaps it’s worth doubling up on the french drain pipe in the absence of gutters.
Appreciate any advice!
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Replies
It is common advice not to do gutters in snow country, but that advice is given because most clients in North America do not want to pay for snow retention. It is complete nonsense and if you look at other snowy regions around the world, like, The Alps, gutters and snow retention are standard items. Of course your roof will need to be strong enough to keep the snow on. Shingles will not slide as bad as metal roof, but the snow will come off. When it does slide, it will pile against the house, create dangerous avalanches for people walking below, rot the lower siding courses and saturate the soils during the spring. Sure you can forego gutters, and the french drain will help, but I feel like it is a part of the project worth investing in.
Thanks for the quick reply. Makes sense -- i've just heard people adamant about not using gutters. Even well respected building science-based designers. Appreciate the perspective
In addition to Strausjw's advice I'll add this. Set the height of the gutter relative to the roof eave so that the outer edge of the gutter is about 1/2" below. As snow inevitably slides off it will less likely catch the gutter.
For shallower slopes I would increase the difference up to an inch.
Here's a tidbit on the topic from Fine Homebuilding.
https://www.finehomebuilding.com/project-guides/roofing/sloping-and-placing-gutters
The one downside I'm aware of is that if you're having a really torrential downpour and the water is sheeting off your roof, it can overshoot the edge of your gutter, just like you want the snow to do when it slides.
Build America gives some advice on how to carry away stormwater if you decide not to have gutters. Scroll down to Figure 5. https://basc.pnnl.gov/resource-guides/gutters-and-downspouts#edit-group-description
You didn't mention two factors that will play a big part in whether this works well or not...roof overhang and siding material near grade. If you have a small overhang, then water will be hitting the siding more easily without gutters. If you have a more water sensitive siding near grade then you're going to have to deal with splashback.
My house in the very wet mountains of the already wet PNW has a two foot overhang and metal siding on the first floor. I have gutters because the county required them, but I could easily get by just fine without them. The gutters are slightly dropped to allow snow to shed, but it hasn't been an issue so far.
In contrast, a modern looking "monopoly" house went up a block away from me with no overhangs at all and it's siding goes green every winter and I heard they're having water intrusion issues already. It looked nice when it was brand new!