Water through flashing vents

[MoDoug]

I'm getting water on top of my stove during heavy rains with strong cross winds. It's only on the outside of the stove pipe, and my best guess is the water is being blown up the chimney pipe roof flashing, under the storm collar and into the ventilation slots. I have SuperVent pipe.

Searching this site I found a post from July 23, 2008, from a poster that says he's VP of Marketing for Selkirk. (Link and text below) He says to use duct tape to seal the vents, because the ventilation is only needed for installations with attics. I have a cathedral ceiling and it sounds like this fix could apply to me, and I would only tape the down slope side. Does anyone have any opinions on using duct tape to block the vents, or any better ideas to prevent water from coming in through the vents?

https://www.hearth.com/talk/threads/leak-around-wood-stove-chimney.17750/#post-269877

 

[paulnlee]

The first time in over 20 years I had some drops on mine during a rainy & windy storm. When I cleaned the chimney I notice it was tilted slightly to the east causing the wind blown rain right into the cap.

 

[MoDoug]

The first time in over 20 years I had some drops on mine during a rainy & windy storm. When I cleaned the chimney I notice it was tilted slightly to the east causing the wind blown rain right into the cap.

As I understand it, if rain comes through the cap it gets wet inside the stove, onto the baffle. Mine is getting rain on the outside of the pipe, onto the top of the stove. It's been several weeks since the last time, but when it did I got onto the roof and checked the caulking around the storm collar, and took the hose up there and sprayed all around the pipe, storm collar and under the flashing and roof shingles. It held up well under that test, which leads me to believe it's coming in through the vent slots.

 

[Highbeam]

It seems particularly difficult for roofers to properly install the roof flashing so it doesn’t leak on composition roofs. Mistakes like using sealant anywhere other than the storm collar, exposed nails, not leaving a half inch gap from cone to shingles, etc.

I am skeptical if it’s the little vents up top.

 

[paulnlee]

Mine came thru the cap and accumulated in the ceiling piece and dripped down the pipe to the stove top.

 

[MoDoug]

It seems particularly difficult for roofers to properly install the roof flashing so it doesn’t leak on composition roofs. Mistakes like using sealant anywhere other than the storm collar, exposed nails, not leaving a half inch gap from cone to shingles, etc.

I am skeptical if it’s the little vents up top.

I did use sealant on the storm collar, and resealed around the manufactured flashing seams before installing. I also used some between the flashing and shingles on the down hill side because there was a gap there after install, and around the nail heads. The nails are galvanized with rubber washers, like used for metal roofs. I thoroughly drenched everything with the hose for a few minutes, even spraying uphill under the flashing and shingles, with no leaks.

I've attached a picture, if something looks out of place, please let me know.

 

[MoDoug]

Mine came thru the cap and accumulated in the ceiling piece and dripped down the pipe to the stove top.

I have the SuperVent deluxe rain cap with my install. With the way it's designed, it's difficult for me to envision how it would come through the cap and work it's way outside of the pipe. That's not saying it can't be the cap, I'm just not seeing it. Maybe I need to put more thought into the cap as the problem. After my water test, it seems to me the vents or the cap are the only way for water to get in. The last storm brought in a significant amount of water in a short time.

 

[Highbeam]

I did use sealant on the storm collar, and resealed around the manufactured flashing seams before installing. I also used some between the flashing and shingles on the down hill side because there was a gap there after install, and around the nail heads. The nails are galvanized with rubber washers, like used for metal roofs. I thoroughly drenched everything with the hose for a few minutes, even spraying uphill under the flashing and shingles, with no leaks.

I've attached a picture, if something looks out of place, please let me know.

Oh yeah, I see mistakes but I’m picky. Those nails should not be there. No visible nails. You didn’t leave 1/2” around the cone. That goop you put under the flashing is preventing your leaks from getting out. I wonder, but not sure, if you could have gotten one more row of shingles on top of the flashing. Lastly, did you goop the storm collar connection seam? Not just the part touching the pipe but the actual connection splice.

I’ve had good roofers beat into me their version of the “right” way.

 

[moresnow]

Its the flashing vents in my opinion. To much venting and not a wide enough storm collar to keep out rain/snow in high winds.

 

[MoDoug]

Oh yeah, I see mistakes but I’m picky. Those nails should not be there. No visible nails. You didn’t leave 1/2” around the cone. That goop you put under the flashing is preventing your leaks from getting out. I wonder, but not sure, if you could have gotten one more row of shingles on top of the flashing. Lastly, did you goop the storm collar connection seam? Not just the part touching the pipe but the actual connection splice.

I’ve had good roofers beat into me their version of the “right” way.

I like picky, I drive my wife crazy being picky. The manufacturer instructions (below) for installing the flashing include the nails, I was trying to install as close to instructions as possible. I can still trim the shingles around the cone, but I don't think the water is coming from there, it passed my hose test. With the goop under the flashing, I felt like it was necessary because the sculpted shingles left gaps for wind blown rain to get under it. The cathedral ceiling box opening is only about 3" from the downhill edge of the flashing. I feel like the watershed off the roof is good. I did goop the storm collar seam after it was installed and bolted together.

I'm picky about my caulking jobs, and I'm not happy with the goop around the storm collar, it doesn't pass my neat job preference, but it looks solid and passes the hose test. Just an FYI, I did not goop the chimney pipe to the flashing, I was told by a Selkirk tech to not do that, because of the sway and expansion.

 

[MoDoug]

Its the flashing vents in my opinion. To much venting and not a wide enough storm collar to keep out rain/snow in high winds.

This is what I've been thinking, because it's only in high winds. I'm new to the world of wood stoves, and realize there's a lot to learn still. The storm collar looks wide, but the vent slots are fairly long under the collar. Like a car windshield in a rain, it seems to me the water can blow up the flashing to the vent slots.

 

[Highbeam]

Can’t hurt to try taping those vents up. Would be an easy fix. Could you do it without removing the pipe?

It’s really not practical to seal all roof vents this way. Other passive ventilation penetrations on the roof, vented ridge, and even gable vents, depend on gravity to keep water out.

 

[MoDoug]

Can’t hurt to try taping those vents up. Would be an easy fix. Could you do it without removing the pipe?

I guess I will try taping, I have some aluminum duct tape that would be good for this. I think I can get by with taping about 1/3 of the vents on the north and downhill side. I should be able to do it without having to remove anything. If i continue to get water in, I'll concentrate on the cap, that would suck because my cap is about 12 feet above the roof.

Thanks for the input. In the mean time I'm still open for any thoughts on this.