Leaking chimney ceiling support box

[wisconsindvm]

Hello everyone,
I had my woodstove installed about 3 years ago. It has a square ceiling support box that protects the pipe from the insulation in the ceiling. It is all double walled pipe. The last couple of rain storms there has been water coming through the box along the edges and corners that are spot welded together. There is nothing coming down along the pipe as far as I can tell, only out of the box. I went up and slathered silicone on the storm collar and everything else I could see as suspicious but it did not fix the problem. Any thoughts on what to do next? Where would you guess the leak is?
Thanks for the advice.
joe

 

[Mt Ski Bum]

Could one of the mods. maybe move this to the "Hearth Room"? You might get more responses there than in the "Wood Shed".

I'm not an expert on chimney installs by any means, but hopefully someone else who know a bit more than I do will chime in & have an idea of what's happening.

 

[3fordasho]

Hello everyone,
I had my woodstove installed about 3 years ago. It has a square ceiling support box that protects the pipe from the insulation in the ceiling. It is all double walled pipe. The last couple of rain storms there has been water coming through the box along the edges and corners that are spot welded together. There is nothing coming down along the pipe as far as I can tell, only out of the box. I went up and slathered silicone on the storm collar and everything else I could see as suspicious but it did not fix the problem. Any thoughts on what to do next? Where would you guess the leak is?
Thanks for the advice.
joe

I've had a similar problem with Supervent double wall class A. Wind driven rain is able to work into the outer wall pipe seam that runs the length of the pipe and follow the seam down. Filling the seam with silicon seems to help but it's started to leak again.... I think some of the id stickers have come off exposing the seam again.

 

[Highbeam]

You have a water leak from the roof. There is a remote possibility that the water is somehow getting in between the layers of your stainless chimney above the roof and then coming out at the bottom but the much much more likely issue is that your roofing/flashing job is not proper. Especially when you speak of gobbing even more silicone up there. I bet that if you take a photo of your flashing/shingling/storm collar job we could tell you what was done wrong. If done properly on a composition roof, there should be absolutely no sealant used on the roof jack, no nail heads visible, and no roofing touching the cone of the roof jack (Look for about a 3/4" gap here). The only place for sealant is the doughnut looking storm collar that clamps to the actual 6" pipe.

I had a similar leak. It dripped from the box corners right onto my stove. I was able to go into the attic and see no water streaks on the shiney SS chimney. In my case, the shingles hadn't been trimmed far enough away from the cone and it allowed water to back up under the shingles and find its way under the roof jack to the wooden roof deck which was wet and dripping right down into the ceiling support box. I cleaned out the accumulated junk, trimmed the shingles, and it's been dry ever since.

 

[wisconsindvm]

Thanks for the help. I posted some pictures. They are the best I can do for now. I did not install this. It was installed professionally about 3 years ago and has never leaked until recently. I liberally applied the silicone (as you can see) but I only went over places that already had some on them. I appreciate any thoughts.
Thanks again
Joe

 

[DAKSY]

Nothing obvious shows here, other than the installer made more work for himself than he needed to.
Is there silicone at the top of the flashing cone UNDER the storm collar?
Looks like a very shallow pitch & the shallow pitch flashings generally have a shorter cone.
This means that the storm collar is closer to the shingles & rain can actually spatter up to
the top of the cone - UNDER the storm collar - hit the chimney & run down the inside.
I'd look to see if the silicone UNDER the storm collar has failed...

 

[Highbeam]

That's a hack job in my area. The roofer should be fired.

The first problem is the three nails that are exposed, there is no reason for that and nails do leak even if they're gasketed. That is why the tar is there to try and stop it. The nails should have been on the sides up under the shingles and no tar is needed.

The next problem is that the roofing extends up to and beneath the cone. The flashing needs to act like a shingle and any water that falls onto the flashing from above the cone needs to be able to escape out the bottom. The flashing should be visible between the cone and the bottom edge of the flashing. That's how water gets out.

Third is that the shingles should be trimmed back from the cone about 3/4". This allows water to fall off of the shingles from above, fall onto the metal flashing, go around the cone freely, and off the bottom without being dammed and pushing up under the shingles. This is your actual problem I believe. All that goop and roofing is making it easier for water to go back under the shingles than to run off down the roof.

The tar. Any time you see tar on a shingle you can be certain that the roofer was a hack. There is only one place in a comp roof job for tar and that is the four nails securing the very last ridge cap shingle.

On the chimney roof jacks that I have seen, the cone does not fit tight to the chimney so it can't be sealed under that storm collar. That's the reason for the storm collar, to shield that big joint.

Even if the water stops dripping out of the ceiling box, keep an eye on the underside of your roof. The wood rot can be silent as it spreads.

 

[skinanbones]

trim the shingles back at lest 3/4 of a inch from the cone as i'm sure thats whats causing you problems.

 

[tfdchief]

I agree with all the critiques, but wonder if that SS chimney joint at the top of the picture could be leaking?