Metal Chimney Pipe Flashing for Ribbed Metal Roof

[kharrisma]

Hi Forum Folke!

I'm installing a woodstove in my new room addition, which has a cathedral ceiling. The stove has a 6" flue, so I'll obviously be using 6" piping.

I'm looking at the DuraVent line of products. Something I find confusing is the chimney pipe flashing. It's a typical "flat metal sheet with a metal cone on it." I can't see how this flashing would seal to a ribbed metal roof. I'm not at all satisfied with the suggestions that one just slobber caulking under it and screw it down; that's not flashing, that's a patch. I've read suggestions that a slot be cut in the roofing up-slope of the chimney pipe and then slide the upper end of the flashing into that slot and under the metal roofing. Well, that's good as far as it goes, but what about the ribs on the roofing panel? Are you supposed to do metal work and shape the thing to conform to the ribs underneath it, or flatten the ribs underneath it for a short distance, or what?

I've also seen that DuraVent has a "flashing for metal roof" as an option for their Cathedral Ceiling Kit, but they don't mention it anywhere else on the site; I'm wondering how it's different from a "normal" flat one. I'd love to fire off a quick email, but there's no email contact. Anyone had any experience with it?

Thanks in advance for any advice!

 

[bholler]

Hi Forum Folke!

I'm installing a woodstove in my new room addition, which has a cathedral ceiling. The stove has a 6" flue, so I'll obviously be using 6" piping.

I'm looking at the DuraVent line of products. Something I find confusing is the chimney pipe flashing. It's a typical "flat metal sheet with a metal cone on it." I can't see how this flashing would seal to a ribbed metal roof. I'm not at all satisfied with the suggestions that one just slobber caulking under it and screw it down; that's not flashing, that's a patch. I've read suggestions that a slot be cut in the roofing up-slope of the chimney pipe and then slide the upper end of the flashing into that slot and under the metal roofing. Well, that's good as far as it goes, but what about the ribs on the roofing panel? Are you supposed to do metal work and shape the thing to conform to the ribs underneath it, or flatten the ribs underneath it for a short distance, or what?

I've also seen that DuraVent has a "flashing for metal roof" as an option for their Cathedral Ceiling Kit, but they don't mention it anywhere else on the site; I'm wondering how it's different from a "normal" flat one. I'd love to fire off a quick email, but there's no email contact. Anyone had any experience with it?

Thanks in advance for any advice!

You can use standard flashing on corrugated metal roofing. You just need to cut a slit in the roofing the width of the flashing so it can slide under

 

[rwhite]

You can use standard flashing on corrugated metal roofing. You just need to cut a slit in the roofing the width of the flashing so it can slide under

That's how I did it. Cut the hole through the roof then cut the slit about 1/2 way up the hole. The flashing will sit on top of the ribs. I used the proper profile foam filler for the bottom edge. I caulked the slit and the top side of the cone.

 

[Wooden Head]

What you should be looking at is a flashing similar to ones that are used for vent pipes on metal roofs. The difference is those used for stove pipe have a silicone collar instead of a rubber collar.

 

[bholler]

What you should be looking at is a flashing similar to ones that are used for vent pipes on metal roofs. The difference is those used for stove pipe have a silicone collar instead of a rubber collar.

I really prefer flashing that doesn't rely on rubber and sealants. Plus they type is not listed for his application.

 

[bholler]

That's how I did it. Cut the hole through the roof then cut the slit about 1/2 way up the hole. The flashing will sit on top of the ribs. I used the proper profile foam filler for the bottom edge. I caulked the slit and the top side of the cone.

That is how i do them

 

[festerw]

What you should be looking at is a flashing similar to ones that are used for vent pipes on metal roofs. The difference is those used for stove pipe have a silicone collar instead of a rubber collar.

This. Silicone works much better than rubber or most caulking.

https://www.amazon.com/dp/B01132G9TY/?tag=hearthamazon-20

 

[Mnpellet]

Excel makes a great flashing for metal roofs.

 

[webby3650]

Excel makes a great flashing for metal roofs.

A traditional flashing made for shingles can be modified to work, but just sliding it under the metal is half assin it. If you want to do it right buy an excel metal roof flashing. Don’t half ass it, whole ass it! Buy the correct product for the job.

 

[bholler]

A traditional flashing made for shingles can be modified to work, but just sliding it under the metal is half assin it. If you want to do it right buy an excel metal roof flashing. Don’t half ass it, whole ass it! Buy the correct product for the job.

There is nothing half assed about using the flashing listed for that chimney. I have used both the excell flashing with excel chimneys and the ventis flashing for metal roofs on ventis chimneys and I really don't find them easier or better than simply using the flat flashing. I don't bother with the metal roof flashing anymore.

 

[webby3650]

There is nothing half assed about using the flashing listed for that chimney. I have used both the excell flashing with excel chimneys and the ventis flashing for metal roofs on ventis chimneys and I really don't find them easier or better than simply using the flat flashing. I don't bother with the metal roof flashing anymore.

That’s strange. They seal up so good. How do you prevent muddobbers and insects from making their way in? Or big air infiltration? Regular flashings can be bent like an excel, just throwing it in like it is though? I don’t get it.

 

[rwhite]

If the flashing hangs over a rib a bit you can trim the edge a bit if you care about the aesthetics.

 

[bholler]

That’s strange. They seal up so good. How do you prevent muddobbers and insects from making their way in? Or big air infiltration? Regular flashings can be bent like an excel, just throwing it in like it is though? I don’t get it.

I use the foam fillers underneath the bottom edge that are used under the ridge vent. It works great and takes half the time.

 

[Kevin Weis]

Are we talking about standing seam metal as opposed to corrugated? On standing the seam is a little over an inch more or less. The only way to use no caulk would be to solder the flashing to the metal (tin) roofing no? That would be costly but could be done.

 

[rwhite]

If the over hang on the ribs bothers you , you can trim a bit off the edges.

 

[rwhite]

Are we talking about standing seam metal as opposed to corrugated? On standing the seam is a little over an inch more or less. The only way to use no caulk would be to solder the flashing to the metal (tin) roofing no? That would be costly but could be done.

Never done a standing seam but it would be easy enough to use a hand brake and bend the bottom half to attach to the seam on the sides. Foam fillers can still be used on the bottom edge.

 

[bholler]

Are we talking about standing seam metal as opposed to corrugated? On standing the seam is a little over an inch more or less. The only way to use no caulk would be to solder the flashing to the metal (tin) roofing no? That would be costly but could be done.

Standing seam is basically done the same as corrugated. Cut the hole in the roofing that the flashing cone will fit through. Then cut a slit on both sides so the flashing can slide up underneath the top. For new standing sean tte bottom is then either bent and cut to fit or filled with the foam filler. For new standing seam I Do usually get the metal roof flashing. Older standing seam the rib can just be bent over on the bottom edgeso the flashing sits flat. The only adalat is a small dab at the end of those slits.

 

[webby3650]

I use the foam fillers underneath the bottom edge that are used under the ridge vent. It works great and takes half the time.

Half the time? That’s not realistic and is relying on foam and sealant rather than a positive connection. It’s inferior. It works, but could be better.

 

[webby3650]

Are we talking about standing seam metal as opposed to corrugated? On standing the seam is a little over an inch more or less. The only way to use no caulk would be to solder the flashing to the metal (tin) roofing no? That would be costly but could be done.

No, the same excel flashing works on both types of roofing.

 

[bholler]

Half the time? That’s not realistic and is relying on foam and sealant rather than a positive connection. It’s inferior. It works, but could be better.

Yes half the time i can really have the flashing in in under 5 mins easily. And there is no more reliance on sealant doing it the way i do than with the metal roof flashing. The foam just closes up the bottom to keep bugs out. Which is pointless on corregated because they can get in at the bottom but that is beside the point. If it is good enough to use the whole lenght of the ridge cap it is good for the bottom edge of the flashing.

There is nothing wrong with using the metal roof stuff i just dont find it worth the additional cost myself when i can make the flat stuff seal just as well. And there is nothing half assed about cutting in the flat flashing at all.

 

[bholler]

No, the same excel flashing works on both types of roofing.

So does ventis

 

[bholler]

If you did have a really picky inspector technically it is against code to use a different brand flashing. I doubt that would ever happen but technically it is possible.

 

[bholler]

Half the time? That’s not realistic and is relying on foam and sealant rather than a positive connection. It’s inferior. It works, but could be better.

We do both agree not to use the silicone boots though lol.

 

[webby3650]

Yes half the time i can really have the flashing in in under 5 mins easily. And there is no more reliance on sealant doing it the way i do than with the metal roof flashing. The foam just closes up the bottom to keep bugs out. Which is pointless on corregated because they can get in at the bottom but that is beside the point. If it is good enough to use the whole lenght of the ridge cap it is good for the bottom edge of the flashing.

There is nothing wrong with using the metal roof stuff i just dont find it worth the additional cost myself when i can make the flat stuff seal just as well. And there is nothing half assed about cutting in the flat flashing at all.

Have you ever modified a standard flashing to work like the excel flashing? It’s not too bad to do.

 

[webby3650]

If you did have a really picky inspector technically it is against code to use a different brand flashing. I doubt that would ever happen but technically it is possible.

That would never happen in my neck of the woods. The inspectors don’t know one end from the other. Most are retired pizza delivery guys...