Discolored Metal Roofing

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jhambley

Member
Sep 16, 2009
65
East Central Kansas
I just started burning my new BlazeKing Princess that was professionally installed. After about four days of continuous use, I'm noticing a light brown discoloration below the SS chimney pipe on my white metal roofing. Should I be worried or is this normal?
 
Sounds like creosote dripping. How far above the roof it the chimney cap? Is the stove connected with double-wall connector pipe?
 
The stove is connected inside the house with a straight run of black stove pipe up to the ceiling collar and then changes to SS double wall the rest of the way out. The pipe is about 5' above the roof penetration and about 2' from the ridge of the roof. I don't think it's dripping because it's down a couple of feet below the roof penetration. Almost like it drifted down to the roof.

Another issue was the sprayed foam insulation (open cell) that was blown on the inside of the roof decking. The insulation contractor sprayed the foam in direct contact with the double wall SS pipe at the roof collar. I questioned him during the install and he assured me it was fine to spray directly on the collar and pipe. I have since read that the foam must stay a minimum of 3" away from any heating device flue or exit. I just stripped that insulation off and I could see several pieces of foam were discolored at the joints of the pipe.
 
Cut the foam minimum 2" from the piping. I would go 3" just to be safe.
 
Is the stove connected with single wall pipe? BK recommends double-wall to keep flue temps higher.
 
Do you have any pictures of it?

RoofSoot.jpg
 
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That picture isn't very clear, but I don't see any sign of a typical chimney flashing?
Can you get a clearer picture close up at the base of the chimney/roof area.
 
Do you think the stain you are seeing can be rust? You have a steel roof that is treated to inhibit rust, but once you cut a hole in it you create a raw edge that will rust if it is exposed to moisture. Can you get on the roof for a close look? If it is rusting from the edge of the hole you can probably fix the problem with a liberal bead of high quality silicone caulk.
 
Do you think the stain you are seeing can be rust? You have a steel roof that is treated to inhibit rust, but once you cut a hole in it you create a raw edge that will rust if it is exposed to moisture. Can you get on the roof for a close look? If it is rusting from the edge of the hole you can probably fix the problem with a liberal bead of high quality silicone caulk.

It's not rust because it wasn't there until I started using the stove about a week ago.
 
That picture isn't very clear, but I don't see any sign of a typical chimney flashing?
Can you get a clearer picture close up at the base of the chimney/roof area.

Agreed. Where is the flashing and storm collar?
 
The


The collar in under the white metal roofing and then they silicone caulked around the penetration. I didn't think the silicone would hold up and would eventually start leaking so I just ordered a Dektite #8 Silicone Hi-Temp Pipe Flashing that I'll have installed when it arrives.
Storm collars do not go under the roofing.
 
Here are a couple examples of what the flashing and storm collar should look like.
As you can see the flashing is clearly visible in both cases, and the storm collar is the collar that fits tight at the top and widens at the bottom to help shed the water away from the chimney. There is no way the storm collar could work properly if it was "under the metal roofing".
roof_flashing.jpg
1211091410-00.jpg
 
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Storm collars do not go under the roofing.

I just climbed up into the attic again to look how the insulated chimney pipe passes through the roofing. It looks like they cut the plywood back about 2-3 inches from the pipe and then cut the white metal roofing very close around the insulated pipe. They then sealed the small crack between the pipe and roofing with clear silicone caulking. That's the area I'm worry will eventually leak so I've order the Dektite collar (see image). He brought out a moldable aluminum storm collar that he said they could install but almost everyone he had installed on seamed metal roofs ended up leaking because they couldn't be hammered tightly enough to fit the roofing.

dektite.jpg
 
Just a note that the Dektite #8 I ordered was good for pipes up to 13". Hopefully that's large enough for the insulated pipe I have (6" flue).

Regardless of the flashing, I'm still not sure why I'm seeing a faint, brown discoloration on the south side of the stove pipe. It appears that the exhaust is falling back onto the roof surface.
 
W

then cut the white metal roofing very close around the insulated pipe. They then sealed the small crack between the pipe and roofing with clear silicone caulking. That's the area I'm worry will eventually leak so I've order the Dektite collar (see image).
.
You can count on it leaking the way they left it. You basically don't have any flashing or storm collar.
That Dektite collar should work if you get it sealed properly. It would still be a good idea to install a standard metal storm collar over top the Dektite collar, similar to the second photo in my last post. If you put a bead of silicon around the chimney and push the storm collar down onto the silicon bead it will seal it up water tight and any water running down the chimney will shed away. That is the purpose of the storm collar
 
Regardless of the flashing, I'm still not sure why I'm seeing a faint, brown discoloration on the south side of the stove pipe. It appears that the exhaust is falling back onto the roof surface.
As begreen said, it is likely creosote dripping of your chimney pipe.
Sounds like creosote dripping. How far above the roof it the chimney cap? Is the stove connected with double-wall connector pipe?
This can happen if you are burning wet wood, burning your fires too cool, or if it is cold and windy outside and the wind cools your chimney cap enough that the smoke condenses on it and drips off.
It is certainly not an ideal thing. If it continues it will stain your roof much worse and the creosote is corrosive and could eventually eat the finish off your metal roofing.
Make sure your wood is as dry as possible, and try to burn as cleanly as possible.

Thanks Lumber Jack. What outside diameter is a 6" double wall insulated pipe?
6" (inside diameter) + 4" (of wall material thickness (2" each side sides) = 8" So you should be fine with that Dektite if it good for pipes up to 13".
 
Good to see you ordered the Dektite silicone (red) booting. What is supporting the pipe inside? A ceiling support box?
 
Cold and windy conditions are all we have in Kansas :)

I've checked the wood with a moisture meter and it's fine. Following BlazeKing's firing instructions.

I'm wondering if replacing the black stove pipe (about first 6') with insulated pipe would help keep flue temperatures higher? The rest of the pipe used is insulated and all in interior/conditioned space before penetrating the roof.
 
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