Snow shedding almost ripped the top of my chimney off

[DonTee]

I have a Duravent 6” flue chimney that I installed last summer. Since it sticks above the roof 5-6’ I installed the brace kit as well. I’m uploading a pic of what position the braces are in, since it’s hard to see from the ground.

Anyways, my house has an 8/12 roof. Usually with light snowfall it will shed snow a few chunks at a time. When we get heavier snowfall (like over a foot), it will usually release it all at once.

I’ve noticed that the snow by the chimney braces wasn’t coming down with the rest of the snow on the roof. And so it built up a little. Probably about a foot. Well today we have temps above freezing, and when the snow came off it bent the braces pretty bad. It pulled the snap ring out of one side of the chimney. So it’s hanging by a thread up there.

Is there a way I can install the braces so this won’t happen again? I thought they were slim enough that the snow would slide past them. I was wrong.

 

[DonTee]

Could I install the braces on the side of the roof (basically to the fascia). Those boards are 1” larch, and are probably strong enough to hold the chimney. I feel that offers less support from front to back winds (which is what we have most of the time).

 

[begreen]

It looks like the brace set screw locks were not set tight enough and got loose. Was a hole drilled through the inner rod so that the lock screw acts as a pin?

 

[begreen]

If heavy snowloads are common it might be a good idea to install a diverter (cricket) up slope from the chimney.

 

[DonTee]

The braces had like a little clamshell clamp that help the inner and outer rod together. Best as I can remember. I did not drill a hole through both pieces and put a locking screw (pin) in. Though I can see where that would have been a good idea.

Yes we do see a bit of snow here.

 

[peakbagger]

IMO with an 8/12 pitch and history of sliding its time to install snow brakes on the roof above plus install snow splitters on the braces and stack.

 

[begreen]

The braces had like a little clamshell clamp that help the inner and outer rod together. Best as I can remember. I did not drill a hole through both pieces and put a locking screw (pin) in. Though I can see where that would have been a good idea.

Yes we do see a bit of snow here.

Looks like the clamshell slipped. If these are Duravent's braces, it's recommended to drill a 1/4" hole through the inner rod to prevent this.

 

[DonTee]

Yep these are the Duravent braces. I must have missed that part in the instructions

These braces are most likely scrap metal now anyways, so next time I’ll do it right. What do you think about moving the braces over to the edge of the roof?

 

[begreen]

What do you think about moving the braces over to the edge of the roof?

That will not brace the chimney pipe effectively. The brace will need replacing. If the brace leg length is 10' or less, one option that might work is to keep the band around the chimney and attach it to legs made of 1/2" EMT (electrical) conduit. You would need to flatten the ends at the appropriate angle and then drill out attachment holes, but that would provide a one-piece leg.

 

[DonTee]

I like the idea of non adjustable braces. Mine are definitely less than 10’. Conduit is a good idea.

 

[RockyMtnGriz]

It looks like it's probably going to be too high for your situation based on the photo, but one thing that can help is to attach the braces very near the peak of the roof. The snow gets much less of a grip on them that way. For those in real big snow country - do yourself a favor, and design things so that pipes exit near the peak.

You could use a snowcutter to remove the snow that's going to attack the braces before it has the chance, but it's definitely work.

I saw someone mention snow brakes. Yes, but make sure your roof is up to the load with a full bad winter's worth of snow on it. I've seen places flattened even without the brakes, and shoveling a steep metal roof, even with brakes, is a scary thing. Brakes get in the way of a snowcutter too, unless there's a couple of feet on the roof, and you're willing to leave a lot behind. And, there's also the drip, drip, drip thing of the winter's snowpack slowly melting off of the roof.

You might also take this as a warning that you need a cricket for the pipe itself.

It would probably be way overkill for your situation, but if you can't solve it any other way, a BIG, stout, custom cricket as tall as your brace can replace the brace rods. Just attach the chimney to the cricket.

 

[MR. GLO]

I have a metal roof but my pipe is at the bottom near gutter so I couldn't really try the snowcutter or splitter....but i installed two s-5 snow bars above it spaced about 3 to 4 feet apart and 8 feet wide. I would install both if i could. You need the snow bars to stop the large snow mass movement and the cutter to protect base of pipe. Even with a cutter a large snow mass will take the pipe off...they make some with a base. And install the splitter on.

Also you can get a bar and install snow clips off them. Bad news is probably 500 to 1000 for parts.

What metal panel is that?

 

[RockyMtnGriz]

A snowcutter is like a roof rake, except it works much, much, better. You'd use it to remove the snow from the roof before it has a chance to wreck something. I don't know the rule about posting links, but Google will find it, and there's a few different takes. I picked up an extra 20 foot stick of tubing at the local metal seller for an extension, and it can do some real damage to the snow piling up on my roof.

A splitter or cricket will protect the pipe, but it has to be a serious splitter. The ones I've seen that are failsafe for extreme conditions extend to very near the roof peak, come up to just below the pipe cap (which should be above max snow depth), or well above max snow depth, and are made of serious metal with internal reinforcements. I've seen a lot of cheesy, off the shelf ones that are the thickness of flashing, and they get squeezed flat until they resemble a shark fin, allowing the pipe to get torn off, or the masonry chimney to get toppled.

It makes sense to dial back from the extreme case to suit local conditions, but I'd always stay away from the thin metal ones. They only look good - for a while.

 

[DonTee]

Thanks for all the suggestions. Right now I got the old braces off and the pipe straightened back up. I’m working on new braces, and at least a solution to get me through to warmer days.

One thing I was wondering, not that it’s going to keep the pipe from going if snow hits it, but do you guys recommend screwing the pieces of chimney together where they interlock?

 

[RockyMtnGriz]

Since no-one else is jumping in, I can't say for your particular brand of pipe, but some use a narrow band type clamp that can be used for further locking the connections together. I don't know the brand of my class a, but it has them. I haven't ever seen a problem from not using them, but at least I'll get you a bump back to the top so maybe one of the chimney pros will see this.

 

[peakbagger]

Living in snow country I see steep slope metal roofs with sewer vents and stove pipes frequently. In most cases an unusual storm event occurs, and damage is done. The homeowner hires someone or does their own fix but all they do is assume that the original install was faulty. In most cases, it is not that it was faulty,its outside the design limits of the system installed. Inevitably a few years later another unusual event occurs and then the final fix goes in which may be ugly but bombproof. It is usually a combination of unusually large crickets upslope of any roof penetrations and snow splitters upstream of any braces. In some cases snow brakes are installed above the penetrations. These are a hassle to install and metal roof salesman usually convince the onwers that they are not needed but by the time the problem shows up he long ago got his commission and is on a new gig.

The concern about a roof not designed to hold the snow pack should not be an issue in NH in any homes built in the last 25 years in the state if they were built to code. About 25 years ago structural engineers in the state working with the Army Cold regions lab in Hanover reviewed snow loading on roofs. One of the big assumptions was roofs do not get shoveled so the snow load should represent whatever the local snow depth can statistically justify. The net result was snow codes in the snowier parts of the state were substantially increased. Contrary to press reports, roofs rarely fail due to snow load as much as they fail due to poor installation where someone skipped the details or someone altered the structure after it was built.

 

[DonTee]

I ended up using some 1/2” water pipe to make new braces. They’re a lot stronger than the brace kit I had before, but I still consider this a temp fix.

Once it gets a little warmer and I can spend some time on the roof, I’ll make a better plan for how to handle the snow next year. I’m hoping my current fix will last the rest of this winter.
I agree i probably need a combination of splitters and snow brakes. And it will be worse next year, because I plan to notch the eve and move the chimney closer to the house. Right now the chimney is outside of the roof on the gable end, so it is safe from snow sliding. Only the braces are in the danger zone.

The house is about ten years old. Trusses were engineered for the snow loads in this area. So I’m good there.

The metal roof came from the Amish. I think it’s 26 awg steel. It still looks almost new after being up there 10 years. One of the reasons I went with a metal roof is because it sheds snow better. My roof will only build up about a foot or slightly more before it sheds. I think that’s the metal roof combined with the 8/12 pitch.

It was kind of a pain today fixing the roof. It’s been above freezing the last couple days, but today it was snowing all day. I didn’t have a ladder tall enough to get to the chimney without getting on the roof, and I didn’t want to get on the roof in the snow. So I called around and found a friend that has a 36’ ladder. My roof is 31’ at the peak, and the chimney is that high also. To meet the 10-2-3 rule.

Anyways, I got the ladder, and used a rope to pull the chimney back level. I was worried if i took the brace off while it was at an angle it would fall off. Once I got the chimney straight again I was able to take the braces off and replace them.

It’s still snowing now, and we are supposed to get a bit tonight. And then it will get cold again. So I’m glad to have the woodstove back up and running!

Thanks guys.

 

[begreen]

.One thing I was wondering, not that it’s going to keep the pipe from going if snow hits it, but do you guys recommend screwing the pieces of chimney together where they interlock?

Yes, so does the manufacturer.

 

[DonTee]

Now you have me doubting myself about the screws, so I reread the instructions that came with the chimney. It says

7. Assemble Chimney Sections: Lower
and seat the female end of the first Chimney Section in the Support Box. (Figure 11). It
will twist-lock onto the male end of a Low Profile Starter Section, which is a component of the Support Box. Turn Pipe Sections clockwise, firmly to lock them together. Sheet metal screws may be used to reinforce the connection, however they are not normally required. Screws are only acceptable in the outer liner.

 

[DonTee]

I think I’m quoting the right part. There is a bunch of info in there about attaching the chimney to the stove pipe with screws, which I did, but I didn’t see anything where it says I have to screw the chimney itself together. Though now that I see it’s an option I might do that.

(broken link removed to https://duravent.com/wp-content/uploads/2019/10/L119_W.pdf)

 

[firefighterjake]

Seeing as you have a metal roof from the Amish it might be worth stopping by to see them about getting a snow diverter. I ended up getting a diverter installed on my own home to protect a vent pipe from breaking from the local Amish . . . a quick and easy installation involving no penetration into the roof -- just a couple of clips which attach to the ribs. I was fortunate as the chimney braces have never had an issue due to the steepness of the roof and location of the mount.

 

[DonTee]

I definitely have to do something different with it over the summer. Right now the chimney is outside the eve on the gable end. This summer I’m going to notch the eve and bring the chimney in closer to the house. At that point it will be right in the path of the snow.

I’m going down to the Amish metal shop soon to see about ordering some roof for a barn. I’ll talk to them about a snow diverter.

The Amish metal roof prices have gone up since I bought my roof from them ten years ago. But it’s still cheaper then buying it from somewhere else. Plus I can support a local business that way. They’re about 15 miles down the road from me.

 

[begreen]

I think I’m quoting the right part. There is a bunch of info in there about attaching the chimney to the stove pipe with screws, which I did, but I didn’t see anything where it says I have to screw the chimney itself together. Though now that I see it’s an option I might do that.

(broken link removed to https://duravent.com/wp-content/uploads/2019/10/L119_W.pdf)

My bad. I should have said, so do some manufacturers. Not all require screwing the pipe together and it may not be necessary for this installation.

 

[DonTee]

No that’s cool. I thought I read the directions well, but I obviously missed the part about putting a screw through the braces after they were extended to length.

This is my first woodstove install from start to finish. I was trying to make sure it was done right.

My building inspector checked it out the other day while he was at my place looking at the insulation and rough plumbing. He was happy with it.