Chimney Pipe Flashing/Boot for Metal Roofs

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task

New Member
Nov 25, 2019
35
Oklahoma
Cannot find the right temp rated boot for a wood stove chimney pipe system penetrating a metal roof. Chimney pipe is Metal Fab - 6TG48, double wall insulated comes out to 9" outside diameter.

When I look at any hi temp boots they all say something about gas fireplaces and stoves, nothing about wood, or all-fuel stoves.

This is a problem because I was thinking that venting gas fireplaces and stoves is not as hot and the parts are not spec'd the same. So I'm suspicious of a silicone boot that's made for gas fireplaces and stoves.

But I'm not find anything specifically rated for wood burning or all fuel...are there any experts here that can weigh in?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,999
central pa
Cannot find the right temp rated boot for a wood stove chimney pipe system penetrating a metal roof. Chimney pipe is Metal Fab - 6TG48, double wall insulated comes out to 9" outside diameter.

When I look at any hi temp boots they all say something about gas fireplaces and stoves, nothing about wood, or all-fuel stoves.

This is a problem because I was thinking that venting gas fireplaces and stoves is not as hot and the parts are not spec'd the same. So I'm suspicious of a silicone boot that's made for gas fireplaces and stoves.

But I'm not find anything specifically rated for wood burning or all fuel...are there any experts here that can weigh in?
Use metal flashing and cut it in. I don't trust the rubber boots long term
 

webby3650

Master of Fire
Sep 2, 2008
11,061
Indiana
We don’t use rubber boots either. We do however remove them because they are leaking and install this flashing . It works really well.
 

task

New Member
Nov 25, 2019
35
Oklahoma
We don’t use rubber boots either. We do however remove them because they are leaking and install this flashing . It works really well.

I would love to use something like this. I'm not seeing how this works though. They don't show what's going on under the hood there, so to speak.

My metal roof ribs are spaced right at 9" apart, and my chimney will require a 13" hole to provide 2" clearance around it, so I'm going to have to seal over at least 1 metal rib, probably 2.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
88,935
South Puget Sound, WA
excel_metal_flash_close.jpg Excel_metal flashing.jpg
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,999
central pa
Ventis makes one like that as well. And it works well but I usually just use regular roof flashing and it works just as well.
 

task

New Member
Nov 25, 2019
35
Oklahoma
Thanks for the pictures begreen.

That looks interesting at the bottom of the flashing, but I'm not entirely sure what's going on at the top there. The one pic that gives a hint is troublesome. Surely I'm missing something - were those ribs cut and just left open?

I really like this flashing though, the specifications are great and would keep me from needing to use a piece of fire stop to brace the chimney pipe for the rubber boot.
 

task

New Member
Nov 25, 2019
35
Oklahoma
Ventis makes one like that as well. And it works well but I usually just use regular roof flashing and it works just as well.

How are you cutting that in? I can't seem to find any videos of anyone doing, and a co-worker recently went through a nightmare of leaks trying to cut his in.

I'll keep looking though....
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,999
central pa
How are you cutting that in? I can't seem to find any videos of anyone doing, and a co-worker recently went through a nightmare of leaks trying to cut his in.

I'll keep looking though....
Just cut the circle the size of the flashing cone. Then half way down cut out on both sides untill you are just slightly narrower than the flashing. Then slide it up in. I use foam fillers made for metal roofing on the bottom to close off the gap. If done right you only need 2 tiny dabs of sealant
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,675
Wisconsin Dells, WI
From when we had an Excel/ICC chimney installed.......
 

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task

New Member
Nov 25, 2019
35
Oklahoma
Just cut the circle the size of the flashing cone. Then half way down cut out on both sides untill you are just slightly narrower than the flashing. Then slide it up in. I use foam fillers made for metal roofing on the bottom to close off the gap. If done right you only need 2 tiny dabs of sealant

Yeah this is precisely what caused a leaking nightmare for a co-worker of mine. Every year he had to climb up to the top of his building and lather sealant all over it. It didn't stop leaking until he took another sheet of metal roofing, cut a U-shaped hole out of it to slip over those two side slits that cause all the leaking. It's a bit of work and I'm not seeing the upside.

I appreciate the help, but when I google and search for flashing pipe on metal roofs it is one rubber boot after another...page after page after page...no one is using metal pipe flashing on metal roofs except for a select few on forums here and there, and there's not enough evidence it's a good idea.

I'm moving forward with this irritating red rubber boot.
 

webby3650

Master of Fire
Sep 2, 2008
11,061
Indiana
there's not enough evidence it's a good idea.
Ok... you asked the pros, we verified that the rubber boot is junk and would never use one.
The excel flashing comes with very detailed instructions.
 
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task

New Member
Nov 25, 2019
35
Oklahoma
But if I can't find a roofer to do it, without leaking..... Then there's the pros here in town that all want to use the hi temp rubber boot.

I cannot verify what you all are saying about excel flashing, or any other metal flashing, for metal roofs. I've got about 5 people looking at me funny over this and I've got nothing to show them to prove anything, or demonstrate how this is better. All they see is needless complication when a boot is standard. All I can do at this point is shrug...
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,999
central pa
But if I can't find a roofer to do it, without leaking..... Then there's the pros here in town that all want to use the hi temp rubber boot.

I cannot verify what you all are saying about excel flashing, or any other metal flashing, for metal roofs. I've got about 5 people looking at me funny over this and I've got nothing to show them to prove anything, or demonstrate how this is better. All they see is needless complication when a boot is standard. All I can do at this point is shrug...
A boot is not standard at all which is why you are having trouble finding the right one. They are a short term fix that relies entirely upon sealant instead of two tiny spots of sealant. And I don't know of any chimney system that has one as part of their ul listed system.
 

task

New Member
Nov 25, 2019
35
Oklahoma
A boot is not standard at all which is why you are having trouble finding the right one. They are a short term fix that relies entirely upon sealant instead of two tiny spots of sealant. And I don't know of any chimney system that has one as part of their ul listed system.

I can't find one single article or video explaining cutting in a metal pipe flashing on a metal roof. Not one.

But I can scroll through pages and pages of videos using a rubber boot. Thick bead of goop, tons of screws, more goop all over everything. Video after video. I can scroll through pages and pages of videos using metal flashing on a shingled roof, video after video. But I can't find one thing on metal flashing on a metal roof. Maybe a homesteader video here or there.

I'm not saying I like it, I'm saying I don't have anything to work with here to convince a single person we should use metal flashing here. I can't point to anything at all, save for a couple of pictures that never show the seal all the way around. I'm in another forum asking roofers about pipe flashings on metal roofs to see what they say.

I try to research this stuff out, but I'm finding that chimney science is not very prolific.
 

Mnpellet

Burning Hunk
Jan 5, 2018
109
Northern Minnesota
Not sure if those pictures were help or not as it seems your mind is already made up. I took these at my dealer before I installed mine it went very easily you can also look up on Excels website the directions on how to do it
 

task

New Member
Nov 25, 2019
35
Oklahoma
Not sure if those pictures were help or not as it seems your mind is already made up. I took these at my dealer before I installed mine it went very easily you can also look up on Excels website the directions on how to do it

Those pictures are a help. It looks like I'm just cutting the flashing box metal to match the profile of the metal roof corrugation or ribs and then caulk that at the base. I can't tell what is or is not being cut in at the top though. That's where the most rain and water action is going to be.

No leaks, huh? It looks like you're relying on goop just like a boot does. Not a criticism, just an observation.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,999
central pa
Those pictures are a help. It looks like I'm just cutting the flashing box metal to match the profile of the metal roof corrugation or ribs and then caulk that at the base. I can't tell what is or is not being cut in at the top though. That's where the most rain and water action is going to be.

No leaks, huh? It looks like you're relying on goop just like a boot does. Not a criticism, just an observation.
No the bottom does not need any sealant at all. Yes the top gets cut in. The only place sealant is needed is the sides of the cut. Which of cut right is just a tiny dab. You may not fond a YouTube video telling you how to do it right. But you won't find a single set of manufacturers instructions telling you how to use a rubber boot with their chimney.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,999
central pa
I can tell you I have never replaced metal flashing unless I was also replacing the chimney. I have replaced many many failed rubber boots with metal though
 
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wagne223

New Member
Jul 10, 2019
40
North Florida
Just to backup what bholler said.....

This is a screen shot of the instructions from Excel.
Hopefully you can zoom in on the image and see it.

I just went to their website and opened the instructions.

There is a box on their homepage that says "Installation instructions "
69267ef477f49fb7001388a2438ed13a.jpg


Sent from my SM-G892A using Tapatalk
 

Grizzerbear

Minister of Fire
Feb 12, 2019
1,028
SW Missoura
If i were home i would post pictures here but mine is just like begreen and others posted. I just used "through the roof" to seal all around mine because its clear and its the best sealant i know of. It holds up really well. If you are worried about the mound of goop look you can buy solar seal to match color of your roof. It works good too. And yea those rubber boots suck. Sun dries them out eventually. I have one on my plumbing vent and it leaked from day one. What did i do.....through the roofed the whole damn thing lol. No leak anymore.
 

Grizzerbear

Minister of Fire
Feb 12, 2019
1,028
SW Missoura
O and i havent had any problems with the flashing as far as leaking. Lots of metal roofs in this area with folks that i know with this setup. If they were prone to leaking i would hear about it and i wouldnt think it would be such a standard here.
 

begreen

Mooderator
Staff member
Nov 18, 2005
88,935
South Puget Sound, WA
Yeah this is precisely what caused a leaking nightmare for a co-worker of mine. Every year he had to climb up to the top of his building and lather sealant all over it. It didn't stop leaking until he took another sheet of metal roofing, cut a U-shaped hole out of it to slip over those two side slits that cause all the leaking. It's a bit of work and I'm not seeing the upside.

I appreciate the help, but when I google and search for flashing pipe on metal roofs it is one rubber boot after another...page after page after page...no one is using metal pipe flashing on metal roofs except for a select few on forums here and there, and there's not enough evidence it's a good idea.

I'm moving forward with this irritating red rubber boot.
I'm afraid you will end up regretting that. They don't have a good history. And instead of just a few screw holes for attachment, there will be a whole circle of them. We have seen many metal roof installs with the Excel flashing here. Done correctly, it will not leak and will stay leak-free over its lifetime. Done right, there will be little caulking or sealant involved.

Excel installation guide - go to page 31 for metal roof flashing

Some prior discussion:

Some metal roof tips including an illustration of using a rubber boot, the most common source of leaks according to the video.
 

task

New Member
Nov 25, 2019
35
Oklahoma
I'm afraid you will end up regretting that. They don't have a good history. And instead of just a few screw holes for attachment, there will be a whole circle of them. We have seen many metal roof installs with the Excel flashing here. Done correctly, it will not leak and will stay leak-free over its lifetime. Done right, there will be little caulking or sealant involved.


Some metal roof tips including an illustration of using a rubber boot, the most common source of leaks according to the video.

The bolded part is what I can't repeat enough. It doesn't matter how amazing this flashing is if I can't see and learn how to do it correctly, and right. It doesn't matter how great it is if no roofer here knows how to do it. That's the point I keep making - if there's nothing but written instructions, then that's a DIY doomed to fail. We've all done things the first time, especially by written word alone - and they aren't as good as the third time, or more. I don't have the time and money to do it 3 times so that the third time is finally done right.

I would be willing to try if I could watch someone do it so I could see the details of the work. I am not convinced - at all - that I'm going to cut into my metal roofing exactly like my co-worker did and not have the same leaking nightmare he had. I haven't heard or seen a single thing that explains why his "slits" leaked but somehow if I do the exact same cut mine will be just fine.

Also...the video does not state the rubber boot is the most common source of leaks - it says that "roof penetrations" are the most common source of leaks. He appears to take no position on boots or metal flashing. And it's disappointing that there is no video on doing the metal flashing instead. I think you have to purchase the series to see all that.

I love this metal flashing. If you'd care to drive to Keystone Lake, Oklahoma I'll pay you to put it in. Been on the phone all day, and still can't find a roofer that doesn't use boots. In fact, there aren't a lot of metal roofers here, I'm finding.