Chimney Flashing Question

Woody5506

Minister of Fire
Feb 14, 2017
694
Rochester NY
I had my PE installed in 2016, very simple install but what I've noticed as of last year when I got up onto the roof to clean the chimney, the flashing seems to be warping a bit, or almost "bubbling" up to the point where if you press on the roof shingles in front of the stack (toward the peak of the roof) where the shingles cover the flashing, there appears to be a fair amount of give. What I thought at first was water was somehow getting under there and rotting out the area, but you can see from the attic space that there is no evidence at all of a leak, all plywood still looks new and dry. This is why I'm assuming it's just the flashing bubbling/warping, I have not pulled back the shingles to really look at it I'm just trying to figure out if this is even that big of an issue since it's not leaking anywhere.

Last year I had a load of locust in the stove take off on me and start a small chimney fire, which I was able to put out quickly. The next day when I went to inspect the pipe is when I discovered this issue. Is it possible the pipe heated enough to warp the flashing?

I'm posting here to see if anyone else has experienced this and what I should do about it. Just leave it or have my installer come deal with it?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
18,615
central pa
I am sure it is possible but pretty unlikely. How did you put it out.
 

Woody5506

Minister of Fire
Feb 14, 2017
694
Rochester NY
shut the air off to the stove, went outside and instantly saw a big puff of smoke and then everything seemed fine. Didn't see anything else wrong with the pipe the next day. Couldn't believe it even happened because I'm good about cleaning the pipe but I think the load of locust just took off like a nuclear reactor and the flames shot up the pipe and ignited what little build up could be ignited.
 

EatenByLimestone

Minister of Fire
Jul 12, 2006
7,035
Schenectady, NY
Got any pics?

Could it be the flashing expanding in the sun and both ends are held down by fasteners? This would cause the middle to rise up.
 
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Woody5506

Minister of Fire
Feb 14, 2017
694
Rochester NY
I'll send a pic later on, there isn't much to see of the roof shingles that are bubbled up, I'd somehow have to take a video to show how much give there is. The only issue I can think of for now is because there is give to it, it seems the pipe itself isn't quite as secure. In other words if I move the pipe with my hands by pushing it toward the "bad" spot of the roof, it seems to move with that warped flashing.
 

Ludlow

Minister of Fire
Jun 4, 2018
1,082
PA
Was it cold when they installed it? Aluminum flashing expands and contracts a great deal in response to temperature. Doubt it was the overfire that caused anything because it would just contract as before once it cooled off.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
18,615
central pa
Was it cold when they installed it? Aluminum flashing expands and contracts a great deal in response to temperature. Doubt it was the overfire that caused anything because it would just contract as before once it cooled off.
If it was heated enough then cooler quickly it cold possible warp. But i think you are correct i doubt that was the issue.
 

Woody5506

Minister of Fire
Feb 14, 2017
694
Rochester NY
Was it cold when they installed it? Aluminum flashing expands and contracts a great deal in response to temperature. Doubt it was the overfire that caused anything because it would just contract as before once it cooled off.
Yes it was installed end of December a few years ago. This would make sense to me, I am still surprised it would be enough to push up the shingles but again if it's not causing any problems is there really anything I should worry about?
 

Highbeam

Minister of Fire
Dec 28, 2006
16,217
Mt. Rainier Foothills, WA
The shingles from above should just lay on top of the flashing. If you didn't cut the shingles back from the cone far enough then debris (and water) can get up under the shingles. It's summer, go out there and lift up the shingles and peak under to see what's holding them up. Bring a screwdriver to sweep away any debris. If the flashing is puckered for some reason then you have some tough choices to make. The flashing might settle back down and be fine or you may want to reset the whole thing which means removing all the shingles.

Plywood can look fine from the bottom but be a puffed up rotten mess on top. The different layers of wood and glue can allow for this.
 
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Woody5506

Minister of Fire
Feb 14, 2017
694
Rochester NY
The shingles from above should just lay on top of the flashing. If you didn't cut the shingles back from the cone far enough then debris (and water) can get up under the shingles. It's summer, go out there and lift up the shingles and peak under to see what's holding them up. Bring a screwdriver to sweep away any debris. If the flashing is puckered for some reason then you have some tough choices to make. The flashing might settle back down and be fine or you may want to reset the whole thing which means removing all the shingles.

Plywood can look fine from the bottom but be a puffed up rotten mess on top. The different layers of wood and glue can allow for this.
Quite honestly I was a bit worried of pulling up the shingles thinking I'd screw something up and have a bigger mess on my hands, rather than just seeing what my installer would do if anything to solve the issue. I think you're right in that the shingles could just have crud under them since my neighbor has 6 huge pines next to my house with pine needles that get everywhere. I'll get up there today and see what I can do, and also take a pic of it.
 

Woody5506

Minister of Fire
Feb 14, 2017
694
Rochester NY
20190805_173227.jpg
20190805_173214.jpg


Where my hand is in the first pic is how far up the roof can be pressed. My best guess at this point is the flashing has just bubbled up from heating/cooling and with that, pushing the shingles up. Likely a non issue that my OCD wood burning self made into a bigger issue.

What is a good silicone to reseal with for these areas?
 

Highbeam

Minister of Fire
Dec 28, 2006
16,217
Mt. Rainier Foothills, WA
No goop.

It looks like the roofer just didn’t cut that top shingle back far enough and it is riding up onto the cone. What you feel collapsing is just the shingle flexing down to the top of the flashing which is laying flat on the roof deck.

Either way, I expect a finger width of flat flashing exposed between the shingle and the cone so I would (or a roofer) be trimming that top shingle back. This allows water and debris to flow cleanly around the cone.
 

Ludlow

Minister of Fire
Jun 4, 2018
1,082
PA
Does it spring back when you push on it? Where your fingers are just happens to be the top edge of the flashing. Like I said, when the flashing was nailed down it may have been cold. Then in the heat of summer the flashing hits 100 degrees in the sun. That makes it expand. When it expands and has a nail on each end, it will puff up in the middle. When it gets cooler it will lay flat. If this is the case there is nothing to worry about. This goes on everyday on every roof. I dont see anything to worry about.
 
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