Leaking chimney seam

[hpeairs]

I have a leaking stovepipe. I don't know the specs of the pipe, other than it is shiny steel where it goes through the roof. In a driving northwest rain, sometimes a little water runs down the outside of the shiny part that is inside and drips on the back of the stove. This happens maybe 8-10 times a year. I called the stove installer back a few times, and he tried a few things but never the right thing. Last year I asked a roofing guy to look at it. He reinstalled the flashing around the base, but it still leaked. Then he went up on the roof and played the garden hose around on the flashing for five minutes (no leaks), then tried the vertical seam on the first section of pipe above the flashing. Immediately water started coming in. Of course this seam points northwest. So, it appears likely that the seam is at fault.

I am wondering if there is a way to patch the seam with some sort of high temp sealant. I'd prefer not to have the chimney disassembled. Any thoughts?

Thanks!
Herv

 

[drz1050]

RTV might work.. but would also look like poo.
http://www.amazon.com/Permatex-81160-High-Temp-Silicone-Gasket/dp/B0002UEN1A

Class A chimney? You could probably solder it... I don't think the outside of the pipe should ever get hot enough to melt it... that would also look much better than the RTV.

 

[Mike n PA]

RTV might work.. but would also look like poo.
http://www.amazon.com/Permatex-81160-High-Temp-Silicone-Gasket/dp/B0002UEN1A

Class A chimney? You could probably solder it... I don't think the outside of the pipe should ever get hot enough to melt it... that would also look much better than the RTV.

I have a leaking stovepipe. I don't know the specs of the pipe, other than it is shiny steel where it goes through the roof. In a driving northwest rain, sometimes a little water runs down the outside of the shiny part that is inside and drips on the back of the stove. This happens maybe 8-10 times a year. I called the stove installer back a few times, and he tried a few things but never the right thing. Last year I asked a roofing guy to look at it. He reinstalled the flashing around the base, but it still leaked. Then he went up on the roof and played the garden hose around on the flashing for five minutes (no leaks), then tried the vertical seam on the first section of pipe above the flashing. Immediately water started coming in. Of course this seam points northwest. So, it appears likely that the seam is at fault.

I am wondering if there is a way to patch the seam with some sort of high temp sealant. I'd prefer not to have the chimney disassembled. Any thoughts?

Thanks!
Herv

Depending on how visible the area is where the water enters the seam , I would recommend a high temp RTV, this link is one I use around exhaust areas on helicopters that seals and bonds very well (pain to scrape off!!). It is red however so not pleasing to eye but it does work well..... As always, surface prep is key to sealing anything!!

Aerospace Sealants AS106 Red RTV Silicone Sealant, 2.8 Ounce Tube - FAA-Approved Alternative to RTV106 https://www.amazon.com/dp/B00BJ5GJ28/ref=cm_sw_r_awd_fABhwb92HJDVT

 

[Mike n PA]

Depending on how visible the area is where the water enters the seam , I would recommend a high temp RTV, this link is one I use around exhaust areas on helicopters that seals and bonds very well (pain to scrape off!!). It is red however so not pleasing to eye but it does work well..... As always, surface prep is key to sealing anything!!

Aerospace Sealants AS106 Red RTV Silicone Sealant, 2.8 Ounce Tube - FAA-Approved Alternative to RTV106 https://www.amazon.com/dp/B00BJ5GJ28/ref=cm_sw_r_awd_fABhwb92HJDVT

This is actually pretty much same thing drz1050 recommended........ I would try it.

 

[begreen]

I would clean it well and use regular GE Silicone II. It has good adhesive properties and is clear. You will not see it from the ground. Temp is not an issue.

 

[hpeairs]

Thanks! I will investigate RTV and GE Silicone II. Appearance is not really an issue because the seam faces in towards the roof and can't really be seen from the ground.

Herv

 

[hpeairs]

Any thoughts on the longevity of RTV vs. GE Silicone II? Clearly the RTV will be ok with sub-zero temps, how about the GE product?

Thanks, Herv

 

[jeff_t]

Silicone II Door & Window is supposed to remain elastic from -55 to 400.

I used gray, and it is barely visible from the ground on the stainless pipe. I worked it into the seam really well with my finger, down to the storm collar. Still flexible, never any problems.

 

[kennyp2339]

I had the same problem a while back, I used all types a silicon, cleaned, recleaned, reapplied, around the storm collar, the long seem on the class a pipe but still had drip issues. I then replaced the storm collar with an extra attic insulation shield (its the same thing, only bigger) applied a new coat of silicon, re-silicone the class a pipe seem and have not had a problem for 2 years.

 

[Mike n PA]

Any thoughts on the longevity of RTV vs. GE Silicone II? Clearly the RTV will be ok with sub-zero temps, how about the GE product?

Thanks, Herv

My experience is the RTV is much more resilient than silicone....

 

[Heatsource]

My experience is the RTV is much more resilient than silicone....

rtv is silicone.

clear basic silicone has held up fine in full sun for 15+ years, but we dont get sub zero temps