New metal roof/snow guard question

[MedicineMan4040]

New metal roof is on.
Eash side of the roof is 21 feet long.
Pitch is 11/12.
Selkirk double wall stainless steel penetrates roof 6 feet from the edge of the roof.
We average (according to Google) 12 inches of snow/year (this year 8 inches).
There is already a snowguard close to the bottom edge of the roof.
This metal roofing company is returning next week to install 6" steel gutters and will
add a second row of snow guard if I want.
Should I ? With 15 feet of 'run' snow has a long way to slide down and hit my chimney.
The snow guard used is continuous/strait metal secured into the metal roof and into the
plywood below (right or wrong I don't know). Why this type of snow guard? The wife liked
the looks better than the 'snowshoes'/small tab looking things.
If you say yes add a second row of snowguard I can place it above the chimney flue but how far?
I know if big big snow areas people make crickets out of metal and place them above the flue.
I don't know if we get enough snow for that?
Any thoughts appreciated.
Attached is what I have so far.
Robert

 

[stoveliker]

Regarding the snow: I'm not sur it matters that you get 12" of snow, what matters is how much snow you can get in one go.

Also I'm no roof penetration expert, but zooming in, the penetration looks funky? That wavy black stuff?

 

[MedicineMan4040]

I think the wavy black stuff is the rubber boot the roofing installers used.
Maybe its not rubber? I had a Selkirk metal flashing but the roofing company insisted
they use what they have always used blah blah blah. I went back and forth with them seemingly
forever on the issue and finally gave up. The roofing company used, is in my area the best money can
buy and they kept saying if i went with metal eventually I'd have a leak...if I went with their boot
it would not. As mentioned I had the metal here if they wanted to. They didn't. At my age it really
is a non issue.

 

[stoveliker]

I believe it's better to have proper flashing than a rubber booth.

 

[MedicineMan4040]

Cant argue with you on that Stoveliker.

 

[EatenByLimestone]

I agree that it matters how big your snowfall is vs how many inches you get in a year.

How many inches do you get in your worst storms?

I believe the steepness of the roof will have the heavy, wet snow sliding off every few inches.

 

[MedicineMan4040]

Biggest this past year was a 4 inch dump......then it semi-melted/refroze then is snowed another 3 inches.

 

[EatenByLimestone]

Talk to your older neighbors. They’ll remember the older storms.

 

[MedicineMan4040]

Older neighbors. Good advice. I fit right in with them, just having moved here 6 months ago, they'd
have the bigger winter picture.

 

[stoveliker]

calling some of our friends up north for the snow questions: @peakbagger @bogieb ?

 

[bigealta]

i doubt there will be an issue with that small amount of snow and your stovepipe, unless the flashing is questionable. The real danger with metal roofs and snow and ice are slides off of the roof hitting people and pets below. An ice slide could be very dangerous if it hit you. Doesn't take to much to do severe damage to your body. Here in utah although metal roofs are desirable some people opt to go with regular fiberglass shingles solely to avoid avalanche slides off the roofs. The roofer actually talked my neighbor out of a metal roof for that reason alone.

But we are taking about single storms that measure in feet in Utah.

 

[MedicineMan4040]

Bigealta thanks for your input.
Luckily during winter we don't 'travel' to the sides of the house where we might be hit.
In the image I posted is one row of snowguard, next week another row goes on further up, above the chimney
flue, but how far 'north' of the chimney flue would you go? a foot, two feet? or more?

 

[bogieb]

I have standing seam roof on my hip roof and don't use snow guards at all. My roof is fairly shallow, so depending on conditions, doesn't dump as often as those with a steeper roof like yours.

My PVC sewer roof vent is a little further than half way up the roof, and I've had no issue with it. I've had up to 30" of wet snow up there a couple of times just in the last 2-3 years.

Honestly, I'm more worried about the vent being covered by snow than being pushed over.

In your situation, I'd worry more about that strap than the chimney itself.

And BTW, when they put the roof on, it leaked around that vent pipe until they put the boot on. Had to replace the ceiling in the bathroom because of a heavy rain the next day. That may speak more to a lousy sealing job, IDK, but the boot instantly cured the issue.

 

[moresnow]

Having a very similar steel roof and same chimney location I personally wouldn't sweat your minimal snow impact. We average 40+/- inches a year with occasional 12" plus events. Never have had an issue. Maybe just lucky? Dunno.

I do have a proper metal chimney flashing, however.

 

[RockyMtnGriz]

I'll agree with everyone who has said that the only thing that matters is your biggest accumulation. With the depths you're talking about though, I don't think you have much to worry about. If I was going to add a second row of guard I'd put it above the chimney where it looks the most pleasing and call it good. It looks like if you split the distance from the existing guard to the top, that would be around a foot above the chimney and that'll work so that's what I would probably do.

Before I added a second row I'd question if I'm adding a maintenance hassle. Is it going to accumulate leaves and junk and be hard to clean? If I thought the answer to that might be yes, I'd probably give it a winter and see how things are behaving then decide if I really needed it.

Regardless, that chimney is pretty tough. I think the most vulnerable part of your install is the brace. Three feet of snow that's had a chance to harden and get a hold on that brace near the mid-point is going to turn it into a U, but 8 inches of snow that hasn't had months to congeal, only pushing on the end where it's supported by the roof isn't going to cause any problem.

In this neck of the woods I wouldn't have a pipe more than a few feet from the peak, even on a comp shingle roof. You also wouldn't see a guard outside of the wall line - that would be asking for an ice dam nightmare. We should be so lucky as to have everything outside of the wall line shed off. But it's still snowing here regularly, so it's a totally different deal.

 

[EatenByLimestone]

I think I read about solar guys using a tennis ball to encourage snow to fall off. It might work well here too.

 

[MedicineMan4040]

EBL tells me more about the tennis ball technique.
Well we've decided to add the second row--it's paid for anyway--and will instruct
the technician to install above the chimney flue and make it pleasing to the eye

 

[stoveliker]

Can you get on the roof to clean out the junk (leaf and other) that will collect behind it?

How much would not cleaning that decrease the lifetime of the roof?

 

[MedicineMan4040]

Stoveliker good question.
It's a metal roof so I'd guess with no cleaning it will last the rest of my life (I'm) 70ish.
So it will be a problem (or not) for the wife.
One thing I've noticed in my immediate area----big wind, a lot. So stuff doesn't stay on the
roof long.

I also rode the neighborhood this morning and looked at other houses' snow guards. Only one
row near the bottom. About half-n-half metal roof to shing roof ratio, but few as steep as mine
with the 11/12 pitch.

 

[coal and wood man]

Had about a foot of snow 3 years ago and the snow slid down the roof and lodged against the chimney. This was on my garage chimney. I did not have any type of snow guard in place and the weight of the snow pushed the chimney down. I have since installed a guard on the roof and additional supports on the chimney. The guard is nothing more than a piece of metal roof flashing bent into a V to channel the snow around the chimney. Luckily this was my garage and I did not have a fire in the stove at the time. Since I do not have gutters on the back of the garage and there is minimal traffic there I do not have snow birds either to break up the snow. Thinking I may add them at some time too.

 

[EatenByLimestone]

EBL tells me more about the tennis ball technique.
Well we've decided to add the second row--it's paid for anyway--and will instruct
the technician to install above the chimney flue and make it pleasing to the eye

The solar guys should be able to tell you more, lol. Their panels need to be clear of snow in order to generate the most. I’ve read about people throwing a tennis ball up onto them to get the snow moving. I can’t imagine it not working on a roof with your pitch.

 

[bigealta]

IDK about snow guard placement. I'd think the second one might be more detrimental than helpful in your area and setup? I have standard 3 tab shingles and 30 year Architectural shingles on my home and rental houses. No metal roofs, so it's just neighbors and builders experiences that i get the metal roof info from.

 

[bogieb]

The solar guys should be able to tell you more, lol. Their panels need to be clear of snow in order to generate the most. I’ve read about people throwing a tennis ball up onto them to get the snow moving. I can’t imagine it not working on a roof with your pitch.

The tennis ball would just sink into the snow and stay there on my panels - LOL I do throw a roof rake up every once in a while just to get some weight off, but with a flattish roof, I can't reach back very far and I really don't care since I'm not off grid and have plenty of credits to use during winter from the net metering.

That being said, the solar panels don't shed snow quite as easily as the standing seam roof does. The panels break up the weight of the snow so there isn't as much pressure building up to start the slide. My north side (no solar panels) still shed snow great and is clear way before the other sides.

 

[MedicineMan4040]

Found this here on Hearth.com
Looks like the same material used to make it is the material that my long straight snow guards
are made from.
I could ask the technician when they return next week for the second row of gutter guard (and whole house
gutter install) if he would do this.
The 'V's' could be placed above the chimney flue but between the long row of snow guards.
Thoughts/see attached.
Wife says it might be overkill here in our location 24361, and I added that it is more holes in the roof
From the very beginning of this project we've tried to do the whole stove/chimney install the right way, but
in some areas there is debate on which way is best.........Like posters above have mentioned, we just don't want
to do something horribly stupid.

 

[stoveliker]

Yes, this would be more useful than a second horizontal row. Less junk collecting, more focused action of what you are adding. And in fact less holes in the roof if this is instead of the long second horizontal thing.