Chimney structural basic questions

[XiNull]

New member, first time wood stove chimney install,

please be gentle

I'm about to install my chimney and cathedral ceiling support box at my cabin. I'm looking at all the parts i got and just mentally thinking about what I'm going to have to do to install each component. But i have a a question that is specific to the cathedral ceiling support box i'm going to be using, and a few other generic questions. Most of them are about structure and stability of the chimney. I really don't want to install something and it being unsafe.

So first off, I'm installing the JM6CCSK SuperVent kit by Selkirk


What's different about this kit, to a lot of other cathedral ceiling kit i've read about, is that the Class A chimney doesn't sit flush at the bottom of the box. There's a support band that gets attached around the class A chimney with a few tiny screws. That support band has a lip all around, and that seems to just sit on another lip/edge at the bottom of the box.

I'm also installing a rubber boot. My roof is corrugated metal, 9/12 pitch, i'm also not good with heights, and this is a first time install. So installing a rubber boot will be simpler for me

here's the support band with the lip

here's the box, showing the lip (view from inside the box)

this is what it looks like with the support band sitting at the bottom of the box

this shows how the support band goes on the class A chimney. it'll have 1 screw/nut to tightened the band, and a few tiny screws that screws into the outside of the class A chimney wall

This is how it'll look like when it's installed (picture taken from the internet). The class A chimney is sticking out by 5-6 inches, and in this case has been spray painted black to look pretty

So my questions

1. How stable is this going to be for the class A chimney sticking up on my roof? The class A chimney is just sitting in the box, on top of a lip. Plus with my rubber boot, which i'm assuming will have some slack. I can't help but imagine my chimney being movable and loose?!? Especially where the band sits on top of the box lip

2. That support box is supposed to handle the weight of the chimney. I'm assuming that's the weight of the chimney that's inside and the box and above it? or another way to put the questions, does the box also support any weight of the chimney below the support box?

3. If the weight of the chimney below the support box is not supported by the box, then what does support it? Does the weight just rely on gravity on top of the stove?

I think that's all i have for now, i'll probably have more questions once i get feedback to my questions

Thanks a lot everyone

 

[begreen]

Lose the rubber boot. That may be ok for plumbing, but not for a chimney. There are purpose-made flashings for metal roofs. The Excel metal roof flashing is a common solution. Take a look at this thread.

Install components....

Greetings one and all. For a new install, would this be a complete, satisfactory ceiling package minus some pipe?

www.hearth.com

The support box supports the weight of the chimney. The stovepipe weight is much less. This is supported by both the support box and the stove.

 

[XiNull]

Thanks for the feedback,

Unfortunatly i already have the rubber boot, and it's non-refundable

I'm not saying that i wont consider the metal flashing. But i already knew exactly how to install the rubber boot. I have no clue how to install the metal flashing. I looked and asked around for this Excel Metal flashing you mentioned. It looks amazing, but i can't find anywhere to purchase it locally. I would probably have to order it online, possibly even in the states (I'm from Canada).

How about a different product, or a different approach? I'll look for some videos on youtube, maybe you have some links to share?!?

cheers

 

[begreen]

I would still not use it. Sell it to someone on eBay or craigslist. Rubber boots require a ton of screw holes and they don't stand up.
The ICC Excel flashing is a Canadian product.

Where to buy – ICC-RSF

icc-rsf.com

Excel Metal Roof Flashing

This is the Excel Metal Roof Flashing, part number ICC EMF

www.woodmanspartsplus.com

or contact these folks and ask them to ship one to you.

Friendly Fires

Friendly Fires is a full-service fireplace and bbq installer in Belleville, Carleton Place, Cobourg, Peterborough, and Kingston, Ontario.

friendlyfires.ca

 

[begreen]

There is also another Canadian part made by Ventis

Ventis Galvalume Non-Vented Metal Roof Flashings

This is a one-of-a-kind design that solves the challenges of Metal Roof Flashings. Available in galvalume & stainless steel. Includes Storm Collar. Trace the metal roof profile on the front edge of the Flashing and cut for a perfect fit. The Integral Snow Wedge on the high side of the Flashing...

chimneycricket.com

It's recommended to put a cricket (snow wedge) above the flashing to divert snow away from the chimney. Heavy wet snow has taken down many a chimney that is not properly protected.

 

[XiNull]

thanks for the links. I noticed a store in my area. No wonder i never heard of them, they are hidden in the industrial park where nobody shops. I'll go take a drive now and check if they have one available

 

[Eman85]

I installed that style chimney kit, been quite a few years ago and it still works fine. My stove is directly under the pipe so I used a telescoping double wall pipe and the stove supports the weight of it. I have a rubber boot on mine and a corrugated metal roof, it works OK but I should put a metal one on. My roof is no where near your roof pitch. I would not want to walk on a metal roof that steep.

 

[XiNull]

I would not want to walk on a metal roof that steep.

I know, and i'm afraid of heights. The camp is on piers about 3 feet high, walls are 10', plus roof another 9'. with that pitch..all that said, i'm pretty high up there to make that install

I went to the store, bought an ICC Excel flashing for an ICC 8"pipe (10"diameter), which should fit my selkirk 6" double wall which is 10" diameter. I should get it in a few days. They actually had one in their warehouse a few hours away.

now i just gotta figure out how to cut my roof metal to slide that in

It's recommended to put a cricket (snow wedge) above the flashing to divert snow away from the chimney

i was going to, need to find one. I wasn't thinking of it when i went to the store a while ago. But i'll ask when i pick up the flashing later this week

 

[begreen]

Is this old Selkirk chimney pipe? Most modern 6" Selkirk sold here is 8" OD but Canada may have a version we don't.

 

[Eman85]

How close is it to the ridge? You might be able to slip the flashing under the ridge cap. Have you walked on your roof yet? Metal roofs in the cool or the shade can be thrilling. I'm getting old and I've had replacement parts installed. I was on my garage that is 4/12 metal on a cold day and slipped, that was it I'm done.

 

[Newbie78]

As noted, lose the boot. It will not work at a 9/12 pitch worth a damn. Even tho Selkirk says it will....

 

[EatenByLimestone]

So, I just want to throw out to the conversation that metal roofs are slippery, especially a 9/12 pitch. If you don’t feel comfortable on the roof, don’t push it. Paying somebody who has the right tools, experience , and safety equipment is cheaper than a hospital bill and physical therapy.

 

[CanFireman]

As noted, lose the boot. It will not work at a 9/12 pitch worth a damn. Even tho Selkirk says it will....

You just trim the bottom end of the storm collar. If using Selkirk boot flashing, it is a listed, certified part. Why use another manufacturer’s flashing?

 

[Newbie78]

It will deform into a weird, folded thing. I installed one on a 10/12 roof. It was chit. Ugly as sin and all folded up weirdly. Totally unsatisfactory, imo. I contacted Selkirk and talked to a very nice lady in their engineering department, sent her pictures, yadayadayada. She agreed with me and prompted a full refund. I then had a good tin shop make me a proper roof jack. Way better.

It would be fine on a 5-6/12 max or so I think, but still ugly as sin. And not nearly the longevity of a piece of sturdy tin, imo.

 

[Newbie78]

Regarding working on a steep, slippery roof:

Two ladders laying on the roof (one each side of your chimney) secured by ropes over the ridge and tied to something immovable on the far side (I used my pickup in this case, I've used other things) will allow you to safely walk up and down the roof. You'll need another ladder to get to the eave, obviously.

That's it; ladders. You could also rig a fall harness if you wanted to.

Or rent a lift, which will likely be more of a pain to actually do the work cause it will be in the way. But doable.

 

[bholler]

You just trim the bottom end of the storm collar. If using Selkirk boot flashing, it is a listed, certified part. Why use another manufacturer’s flashing?

Because the rubber boots are crap that always leak after a few years

 

[Newbie78]

 

[jjam]

New member, first time wood stove chimney install,

please be gentle

I'm about to install my chimney and cathedral ceiling support box at my cabin. I'm looking at all the parts i got and just mentally thinking about what I'm going to have to do to install each component. But i have a a question that is specific to the cathedral ceiling support box i'm going to be using, and a few other generic questions. Most of them are about structure and stability of the chimney. I really don't want to install something and it being unsafe.

So first off, I'm installing the JM6CCSK SuperVent kit by Selkirk
View attachment 314687

What's different about this kit, to a lot of other cathedral ceiling kit i've read about, is that the Class A chimney doesn't sit flush at the bottom of the box. There's a support band that gets attached around the class A chimney with a few tiny screws. That support band has a lip all around, and that seems to just sit on another lip/edge at the bottom of the box.

I'm also installing a rubber boot. My roof is corrugated metal, 9/12 pitch, i'm also not good with heights, and this is a first time install. So installing a rubber boot will be simpler for me
View attachment 314695

here's the support band with the lip
View attachment 314689

here's the box, showing the lip (view from inside the box)
View attachment 314693

this is what it looks like with the support band sitting at the bottom of the box
View attachment 314691

this shows how the support band goes on the class A chimney. it'll have 1 screw/nut to tightened the band, and a few tiny screws that screws into the outside of the class A chimney wall
View attachment 314692

This is how it'll look like when it's installed (picture taken from the internet). The class A chimney is sticking out by 5-6 inches, and in this case has been spray painted black to look pretty
View attachment 314694

So my questions

1. How stable is this going to be for the class A chimney sticking up on my roof? The class A chimney is just sitting in the box, on top of a lip. Plus with my rubber boot, which i'm assuming will have some slack. I can't help but imagine my chimney being movable and loose?!? Especially where the band sits on top of the box lip

2. That support box is supposed to handle the weight of the chimney. I'm assuming that's the weight of the chimney that's inside and the box and above it? or another way to put the questions, does the box also support any weight of the chimney below the support box?

3. If the weight of the chimney below the support box is not supported by the box, then what does support it? Does the weight just rely on gravity on top of the stove?

I think that's all i have for now, i'll probably have more questions once i get feedback to my questions

Thanks a lot everyone

There are thousands of these systems installed right now / it is plenty strong, and a tested component / a professional installer inserts the metal flashing under the roof by doing a horizontal cut above the flashing set point

 

[Newbie78]

It will end up in some way, shape, or form similar to that.

That being said, my roof is 10/12 and my boot wasn't as "snorkelled" as yours appears to be. I just left the annoying boot on and installed an oversize custom jack over it all.

I won't be using a rubber boot on a chimney ever again. I thought it would be convenient and somewhat acceptably attractive too. I was wrong. It was a pita and also very ugly.

Oh, and I just stuck that on with white silicone I had laying around because at that point I knew I wasn't going to use it and I didn't want to use my fancy silicone. But I had to keep the weather out while I sorted out Plan B

Also, my selkirk "sentinel" chimney is 10 1/2" OD and 6" ID, which is bigger than most because it has 2 1/4" insulation, not 1", so that changes how a boot will conform too. The boot I got needed ellipses molded in for cutting guides, not circles. And that would have conformed better without the crappy folds. But it would have still been ugly as sin and chit.

 

[bholler]

View attachment 325917

Yup they are junk

 

[Newbie78]

I know, and i'm afraid of heights. The camp is on piers about 3 feet high, walls are 10', plus roof another 9'. with that pitch..all that said, i'm pretty high up there to make that install

I went to the store, bought an ICC Excel flashing for an ICC 8"pipe (10"diameter), which should fit my selkirk 6" double wall which is 10" diameter. I should get it in a few days. They actually had one in their warehouse a few hours away.

now i just gotta figure out how to cut my roof metal to slide that in


i was going to, need to find one. I wasn't thinking of it when i went to the store a while ago. But i'll ask when i pick up the flashing later this week

I know you are well into this. But...any decent tin basher shop can make anything you want out of sheet metal. And they will make it out of heavier material than the chimney mfrs supply, which is bare minimum, engineering wise. I'd call it flimsy as opposed to sturdy.

 

[begreen]

Yup they are junk

It looks worse close up. There must be 50 screws holding it down. That's crazy!

 

[Newbie78]

Lol. Yup, lots of screws. Lots of silicone, all screw holes filled with silicone. 1" thick 8" wide shiplap roof sheathing. That sucker is THERE. I might have gotten a little carried away, but it only takes a few extra screws to make it look that way. I also washed the flange area on the roof really good with soap and water, water, and then alcohol. The rubber boot only with alcohol. Anyway, I don't like those boots one bit, especially on a steep roof.

 

[begreen]

The idea of a black rubber tub collecting water and ice while exposed to heat and UV sounds short lived to me.

 

[EatenByLimestone]

It sounds like it has the potential to be exciting though! Nobody tells good stories about how they went to the supermarket and found their favorite bag of chips on the endcap.