Got Rain Water Coming In Thru My Flue Wall Plate

[carlo]

My flue goes up 4' and then 90 degree angle out the wall and then straight up along the outside of the house. With all the rain we're getting and gusty winds I'm starting to get water coming in at the base of the indoor wall plate that houses the flue pipe. I checked outside at the caulking and everything looks well sealed in regards to the outside wall plate.

What I did notice is all the seams at the pipe connections outside. I was wondering if rain water can get in thru these seams. I would have thought that they connect in a way where they wouldn't allow water to penetrate. Am I right in this assumption ?

But if rain water is indeed coming thru these seams wouldn't the water be contained within the piping and not come in at the base of the indoor wall plate and drip down my wall ? Any type of guesses would be appreciated. A picture of my setup is included.

 

[cmonSTART]

I sort of doubt water is entering through the seams in the chimney pipe. It would have to contend with two layers of metal and all the insulation in there. More likely its just finding its way in through the wall plate somehow or maybe even somewhere above the whole works, like the roof or a window and running down the inside of the siding.

Maybe someone will have a different take on this.

 

[carlo]

At the T connection seam going into the house there is a thick layer of caulking and it is a tight seal all around. Along the sides of the outside wall plate the seal is solid also. But at the top of the outside wall plate there is nothing, the edge of the siding butts up against the top of the wall plate. In the picture you'll notice I put a piece of duct tape over the top of the plate so the rain would not drip into the tiny opening. But after doing this I was still getting water. Maybe the water was moving sideways under the tape ? I dunno. I will seal the top of the plate when the weather gets better.

There was a steady flow of rain running down the pipe. A non stop hard flow actually, and that's why I thought the the water could get into the seams along the pipe. When I put duct tape on the pipe to deflect the steady flow of water from hitting the seams I still got water inside. Oh well.

 

[Mad Tom]

Could be the duct tape area. Aside from caulking it ,I would wedge a piece of flashing up under the higher flashing and have it flow over the suspected seam. Paint it white to match the siding.

 

[carlo]

Could be the duct tape area. Aside from caulking it ,I would wedge a piece of flashing up under the higher flashing and have it flow over the suspected seam. Paint it white to match the siding.

makes sense ... i think i'll try that

 

[tiber]

I don't mean to be the code nazi but I'm going to be concerned about fire code. Unless your siding is some kind of noncombustable material, it's probably too close to the thimble. What it looks like is you have wall-siding-flashing-chimney in that order. If that's standard issue plastic siding, it's not fireproof by a long shot. So, check that first.

Next it looks like the flashing and the support is screwed through the siding into the framing, which also is no good. (Tt's also missing a screw). Not only will the wind eventually lift the siding off the house but what happens when it's time to replace or upgrade your siding? Try it - on any other wall of the house try to slide the siding left and right. It should have an inch of play, maybe more but it shouldn't be much less. Without the play, the siding can't flex in the wind and it'll pull off.

What you need to do is cut the siding under the chimney supports, screw in a piece of wood so it has a standoff, and screw the chimney to the wood. That will let the siding do it's job, and it may clear up any water problems you have. After that you can get crazy with flashing and whatnot.

 

[carlo]

Thanks for that advice. A fire marshal inspected the job for the permit and he gave it a thumbs up after looking at the specs. I think my outdoor pipe is triple insulated for it's proximity to the house. Hopefully it's safe.

I understand the movement that siding needs, but so far the siding looks OK besides needing a cleaning. I've had the stove for 2 years and this is the first time I've experienced water coming into the house at the junction. It was a very bad storm with lots of rain and gusty winds. As a homeowner for many years I've seen fluke events like this happen after wild weather. Not sure if this is a fluke or not, so I will keep a keen eye on the situation going forward. If it happens again after applying some cheap fixes I think I will heed your quality advice.

 

[begreen]

Just a thought, does the bottom of the outside plate of the thimble have some weep holes or breaks in the sealant to drain trapped moisture?

With the biblical rains the NE is getting, I could see a submarine springing leaks there. Try one fix at a time in the summer and test with a good steady blast from the garden hose. It could be that the bond with the silicone sealant has let loose somewhere.

 

[carlo]

Just checked the whole setup. All the sealant is tight as can be. There are small areas at the bottom of the plate where that bracket screws in that are not tightly sealed, but sealed. I would assume trapped moisture can be drained by this. Seems to me the top of the plate can be the culprit. It butts up tight to the siding but with side way rain I could possibly see water getting in there. There is no sealant in that very small crevice on the top of the plate. I'm gonna start there ang see what happens.

But just wanna make sure .... is it possible for water to come down the chimney and then sit in the horizontal pipe leading into the house and leak at a seam inside the wall ?

 

[fbelec]

at this point with the stove not running you should take it all apart to check. this time you see the water because of the heavy rain, but what about the regular rain storms? it could leak in the wall and you not even aware of it happening. if it's leaking in the wall your going to get rot, mold, ants.
just a thought.