Metal Chimney Pipe Flashing for Ribbed Metal Roof

[bholler]

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

Yes but i dont see the need at all

 

[bholler]

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...

I agree like i said i dont think it will happen. And i see no safety issue at all but technically it doesnt meet code.

 

[kharrisma]

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.

Wow... jackpot! Thanks for all the replies, guys!

I've seen exactly one small pic of what I believe is the "flashing for metal roofs." It appears to be a "wedge" shape, with sides bent to 90 degrees, starting from almost nothing at the upslope end of the flashing, to about a half-inch or so (calibrated eyeball) at the downslope end, with a matching half-inch 90 degree bend, forming a shallow "wedge" shape. You're then supposed to profile the downslope 'base' of the wedge to fit the roof, notching for the rib(s). I'm not quite sure about the sides... supposed to run a bead of caulk then sit the flashing down into it? Run a bead of caulking along the length of the sides? I didn't see a "foot" bend at the bottom of the 'wedge-bend' along the sides... looked like a straight cut. A little more work, but probably better than a foam seal; I really don't like to rely on caulking, as I've seen what prolonged exposure to sunlight's UV component, and the high temps of the roof in Summer can cause. Thanks for confirming that the slotting technique works.

 

[kharrisma]

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.

Yeah... I've seen 'em. I just don't like relying on a "rubber boot" type of sealing, even if it is high-temp silicone. UV light just destroys everything in time, except metal. Too, I've seen boot seals like that split due to the constant stretch that the pipe or shaft or what have you exerts on the boot (and I realize that they shouldn't be installed with a hole that's too small for what's going through it... which is a judgement call, and thus open to error.) AND, it still sits completely on top of the roof. Again: that's a patch, not flashing. Flashing is a mechanical means of diverting water, and relies on nothing other than overlap to do its job. Yes, flashing can fail under specific circumstances, such as ice dams, where the 'patch' method wouldn't, but the benefits or not relying on sealants and boots outweighs that risk, in my book anyway.

 

[mark cline]

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

I used the silicone boot about 3 years ago. Only problem I had was snow and Ice sliding down the roof, pushed the boot down and snow melting leaked down the outside of the pipe . I installed a dam of stops to prevent the sliding and holding the ice and snow above the pipe . The silicone has a flexible metal sealing edge that is screwed down at 1 in intervals ,completely sealing all edges.

 

[kharrisma]

I just found a better pic of that specialized flashing for metal roofing:



They're made of stainless, and aren't too awfully expensive. Here's the url:

https://www.woodmanspartsplus.com/65645/794228/Chimney/Excel-Metal-Roof-Flashing.html

This looks more like the way I think I want to go. Still wish the sides had another 90-degree "foot" bend, though.

 

[Mnpellet]

Mine had another 90* bend where you screwed it to roof. I’m guessing if you check that one will also.

I just found a better pic of that specialized flashing for metal roofing:

View attachment 242246

They're made of stainless, and aren't too awfully expensive. Here's the url:

https://www.woodmanspartsplus.com/65645/794228/Chimney/Excel-Metal-Roof-Flashing.html

This looks more like the way I think I want to go. Still wish the sides had another 90-degree "foot" bend, though.

 

[bholler]

I just found a better pic of that specialized flashing for metal roofing:

View attachment 242246

They're made of stainless, and aren't too awfully expensive. Here's the url:

https://www.woodmanspartsplus.com/65645/794228/Chimney/Excel-Metal-Roof-Flashing.html

This looks more like the way I think I want to go. Still wish the sides had another 90-degree "foot" bend, though.

Even if it has an extra bend i wouldnt screw through it. Those are just extra unnecessary holes in the roof. 2 roofing screws at the top and 2 at the bottom through the rib are all that is needed. If you use screws on the edge like thatand water gets under the flashing it will go through the screw holes.

 

[bholler]

Wow... jackpot! Thanks for all the replies, guys!

I've seen exactly one small pic of what I believe is the "flashing for metal roofs." It appears to be a "wedge" shape, with sides bent to 90 degrees, starting from almost nothing at the upslope end of the flashing, to about a half-inch or so (calibrated eyeball) at the downslope end, with a matching half-inch 90 degree bend, forming a shallow "wedge" shape. You're then supposed to profile the downslope 'base' of the wedge to fit the roof, notching for the rib(s). I'm not quite sure about the sides... supposed to run a bead of caulk then sit the flashing down into it? Run a bead of caulking along the length of the sides? I didn't see a "foot" bend at the bottom of the 'wedge-bend' along the sides... looked like a straight cut. A little more work, but probably better than a foam seal; I really don't like to rely on caulking, as I've seen what prolonged exposure to sunlight's UV component, and the high temps of the roof in Summer can cause. Thanks for confirming that the slotting technique works.

Using flat and foam ridgecap seal doesnt rely on sealant to keep water out any more than the flashing made for metal roofs does. The foam just closes up the bottom to stop bugs and air infiltration the same as it does under the ridge cap.

 

[bholler]

I will add i have absolutely no problem with either the excel or ventis metal roof flashings. I have used both and they both work well. Just personally i dont see that the minor benifits are worth the extra time or cost of the flashing to me.

 

[webby3650]

I just found a better pic of that specialized flashing for metal roofing:

View attachment 242246

They're made of stainless, and aren't too awfully expensive. Here's the url:

https://www.woodmanspartsplus.com/65645/794228/Chimney/Excel-Metal-Roof-Flashing.html

This looks more like the way I think I want to go. Still wish the sides had another 90-degree "foot" bend, though.

They do have a return bend on the sides that sits flat on the roof.
They are galva-lume, I’ve never seen one in Stainless.

 

[bholler]

They do have a return bend on the sides that sits flat on the roof.
They are galva-lume, I’ve never seen one in Stainless.

Ventis makes stainless ones.