Slight water leak from wood stove chimney.

[INresponse]

I built my home and installed the wood stove and chimney. I live in the high desert so we don't get a lot of rain but when we do get a good rain I get some water dripping down the chimney onto the stove top. When I installed it I used the appropriate sealant around the pipe above the roof line, and used the rain collar, but it still leaked. I then added more sealant and a second rain collar. It is not leaking from the roof or the edges of the opening, it is dripping down the outside of the chimney pipe. The inside of the roof doesn't get wet, and the insulation outside the chimney box is dry. I just installed the drywall so I had access to everything above until a few days ago.

Any suggestions on how to stop this leak? Do I need to peel back all the sealant on the roof around the pipe and do it again? Or is this not uncommon for some lucky folk?


Being in a desert the moisture inside is actually helpful, and as soon as the rain stops the drip stops and everything dries up within hours or less.

 

[The Lazy L]

Could the rain be running down the outside of the chimney pipe, find a screw where pipe sections were fastened together, entering the screw hole to drip inside?

 

[SLADE]

This will sound silly but if the outside pressure is greater than the inside you will get small leaks.
If you start a fire in the stove and the house warms the leak will stop.

 

[Cascadian]

Damned if I know but when you figure it out we can both be happy. We had ours installed for insurance purposes. Every once in awhile it leaks a little, fire or not. The stove guy just stopped coming out and trying.

 

[backlash]

My propane furnace leaks water on the inside of the pipe when it rains hard. About once a year or so. There is a rain cap on it but water still manages to get inside the exhaust pipe. I just clean up the water and move on.
I would try spraying the roof with a hose and see if you can spot the leak,

 

[INresponse]

First, I am relieved that I am not the only one with this problem, and now I am not as concerned as I was this morning.

Could the rain be running down the outside of the chimney pipe, find a screw where pipe sections were fastened together, entering the screw hole to drip inside?

This is a good possibility. The chimney pipe is 3-wall so it is very possible it is coming in a screw hole and able to work it's way down without evaporating.

This will sound silly but if the outside pressure is greater than the inside you will get small leaks.
If you start a fire in the stove and the house warms the leak will stop.

This would be possible but the fire was hot and burning all night but the drip was still there this morning when the rain started. And, in the past I had the fire going good to keep the unfinished house (almost) warm and it was still leaking.

Damned if I know but when you figure it out we can both be happy. We had ours installed for insurance purposes. Every once in awhile it leaks a little, fire or not. The stove guy just stopped coming out and trying.

Sorry to hear you have the same problem, but happy I am not alone.

My propane furnace leaks water on the inside of the pipe when it rains hard. About once a year or so. There is a rain cap on it but water still manages to get inside the exhaust pipe. I just clean up the water and move on.
I would try spraying the roof with a hose and see if you can spot the leak,

I can see it on a furnace because the heat is only there when the furnace is running. My wood stove was burning all night so any rain that makes it through the rain cap openings should be evaporating as soon as it hits the heat. The hose is a good idea but I don't think I could isolate the point of entry because I don't see anything until it leaks out the bottom of the chimney box and drops onto the stove top.

I think when I get a chance I will ty The Lazy L's suggestion and check the screws that hold the chimney sections together. My guess is that makes the most sense based on what I am seeing.

Thank you all for the comments. Very much appreciated.

 

[cbrianroll]

A picture would help me alot. To tell the pitch, roofing material, etc...in my neck of the woods water will find a way....its like living in a dishwasher....makes tracking down leaks very frustrating.

 

[INresponse]

A picture would help me alot. To tell the pitch, roofing material, etc...in my neck of the woods water will find a way....its like living in a dishwasher....makes tracking down leaks very frustrating.

The roof is a 7-12 pitch, metal roofing. There are no signs of water inside the roof, on the OSB, or the fiberglass insulation or vapor barrier on the insulation. The water is getting into the chimney box and slowly dripping out the bottom of the chimney box, through the screw holes that secure the chimney box to the flange on the chimney pipe. Nothing else gets wet, and no water stains anywhere inside the roof near the chimney. As I just started installing the drywall I was able to check the area thoroughly in the past, even during rain storms. The water is somehow getting into the chimney box and I think guess by The Lazy L in his post above makes the best sense so far.
It's dark now so a picture of the roof would have to wait, but after reading all the comments above and thinking about everywhere I looked and how I resealed the outside of the chimney where it enters the roof I feel pretty confident it is somehow leaking into the triple wall chimney pipe and dripping down into the chimney box. I had 2 days of rain, but it only leaked the one morning when the wind was blowing the rain at a 45* angle.

 

[cbrianroll]

Yup, that's a fun one lol. 7_12 is pretty steep, water should run off nicely. I like metal metal roofs but hate flashing them.

 

[Caribou]

Starting with a clean roof jack, put new sealant around the seam where the flue pipe exits the roof jack. Put your rain collar as low as practical and add plenty of sealant. I have also sometimes figured out about where my rain flashing will sit, put a bead of sealant just above that line and bedded my rain flashing into the wet sealant and then ran another bead around the top. Some people wipe their sealant nice and thin. I like a heavier layer as that has less tendency to crack.

Some roof jacks have ventilation holes near the top. You may require a deeper rain collar, they do sell them.

Your chimney may need guy wires or braces. If the wind moves the chimney back and forth the sealant may not remain intact.

 

[INresponse]

Starting with a clean roof jack, put new sealant around the seam where the flue pipe exits the roof jack. Put your rain collar as low as practical and add plenty of sealant. I have also sometimes figured out about where my rain flashing will sit, put a bead of sealant just above that line and bedded my rain flashing into the wet sealant and then ran another bead around the top. Some people wipe their sealant nice and thin. I like a heavier layer as that has less tendency to crack.

Some roof jacks have ventilation holes near the top. You may require a deeper rain collar, they do sell them.

Your chimney may need guy wires or braces. If the wind moves the chimney back and forth the sealant may not remain intact.

Sounds about like what I did for the install. I have a large rain collar down low, and a second rain collar a little higher. I installed the second one the next year thinking it needed help to prevent the leak, but that didn't help.

What I need to do is climb up there and check and probably seal the screws that hold the triple wall chimney pipe sections together. I may also need a better rain guard for the chimney cap. The leak only happens when it is windy and the rain is coming down at a sharp angle, so maybe it is coming in to the chimney from the top, if not through a screw hole in the sides.

 

[Caribou]

You can see the water running down the outside of the pipe?

 

[INresponse]

You can see the water running down the outside of the pipe?

No. It just drips out the bottom of the chimney box. This is a picture off the internet but where the red dots are on this picture I have screws that connect the bottom of the chimney box to the bottom of the triwall chimney that extends through the roof. The water slowly drips out of the holes where the screws are located.
It will be too difficult to remove this box to look inside, and then the wait for the next rainstorm could be months. Before I added more sealant and the second rain collar I sprayed the chimney with the hose but no water dripped out the bottom. Either I didn't get the water to the right spot or it just didn't get enough water into the small opening for it to make its way to the bottom.

 

[Cabin Fever]

This is a long shot, but do you think that during a rainstorm that the humidity inside of your attic increases significantly? The humidity then condenses on the cold exposed metal surface of the chimney pipe inside of the attic? Once the condensation builds up it may start to run down the chimney pipe and into the chimney box? The reason I mention this is during cool, damp weather the indoor surface of our metal shed roof always collects condensation. The next morning I'll go out to the shed and find drips spots here and there where the accumulated condensation has dripped. Like I said, this happens to us during cool, damp weather, it doesn't even have to rain for this to happen.

 

[INresponse]

This is a long shot, but do you think that during a rainstorm that the humidity inside of your attic increases significantly? The humidity then condenses on the cold exposed metal surface of the chimney pipe inside of the attic? Once the condensation builds up it may start to run down the chimney pipe and into the chimney box? The reason I mention this is during cool, damp weather the indoor surface of our metal shed roof always collects condensation. The next morning I'll go out to the shed and find drips spots here and there where the accumulated condensation has dripped. Like I said, this happens to us during cool, damp weather, it doesn't even have to rain for this to happen.

I have not seen any evidence of that, but while the wood stove is burning everything in the area has been plenty warm and dry, especially with the dry desert air. Even with two days of rain we were still getting static shocks inside the house. The house is not completed yet so there is still plenty of air movement everywhere. I just installed most of the drywall in the kitchen living room over the last week. There are no signs of water anywhere outside of that chimney box.

 

[Caribou]

Do the screws go into the pipe or straight up towards the roof?

 

[INresponse]

If I remember correctly screws go into the bottom of the bottom section of triwall chimney pipe. That was the design of the chimney. That is why I am thinking the guess by The Lazy L may be correct. It water is slowly leaking into the holes for the screws that hold each chimney section together it would slowly work its way down the chimney, in the outer chamber. There is the actual chimney pipe, then the first heat shield that is inside the outer heat shield. I am thinking the outer section doesn't get hot enough to evaporate any water that leaks in through the screw holes.
Eventually I will get up on the roof and look for a loose screw, or other signs of an opening, where wind driven rain could enter the chimney pipe. But, I have about 100 other projects going on as I am still trying to finish building the house myself so this small leak that is not causing any damage to the house is not very high on the to do list. I also need to make a repair to one of the guy wires so maybe I will get too it sooner than later so I can fix two things at once and report back on what I find, or don't find. I hate keeping you all waiting, but priority priorities come first.

 

[INresponse]

(Mod edited spammer info)
Thank you for the information. Recently I rebuilt the chimney and reinforced it from the snow when it slides off the roof. Inspection proved it is not, and was not, leaking from the outside of the pipe or the roof. The inside of the roof, the insulation, and the drywall show no signs at all of water. After the rebuild the water coming in is about 50% or less but there is still some during a good rain fall. I don't see any other way for water to come in other than at the top in between the inner and outer chimney walls.

 

[Tirediron]

bear in mind under the right conditions, water will wick up hill, I think roofers say up to 1 1/2 inches verticle, so check into the down hill side of things, wind driven water can do some strange things. The chimney box only protrudes into your attic space, correct, if so water should not be able to get to the box from outside. And do yourself a favour and build a removable panel of dry wall around where the chimney box enters the roof drywall, so if you have to work on the box or chimney you don't end up having to patch and paint. If you can, try using a garden hose in specific areas to see if you can make it leak under controlled conditions

 

[INresponse]

(Mod edited spammer info)
Thank you for the information. Recently I rebuilt the chimney and reinforced it from the snow when it slides off the roof. Inspection proved it is not, and was not, leaking from the outside of the pipe or the roof. The inside of the roof, the insulation, and the drywall show no signs at all of water. After the rebuild the water coming in is about 50% or less but there is still some during a good rain fall. I don't see any other way for water to come in other than at the top in between the inner and outer chimney walls.

Good catch by our Mods. I didn't even think about that poster being a spammer. I know he posted a link to a company but didn't look at his information or if he was new. But, as I was reading it I thought it was strange how he was pushing me to call in a "professional" to look for the obvious. Anyways, thanks for giving him the axe and deleting his post. However it was good that he bumped the old thread so I could add my video of (sort of) fixing the problem I was having.

 

[INresponse]

bear in mind under the right conditions, water will wick up hill, I think roofers say up to 1 1/2 inches verticle, so check into the down hill side of things, wind driven water can do some strange things. The chimney box only protrudes into your attic space, correct, if so water should not be able to get to the box from outside. And do yourself a favour and build a removable panel of dry wall around where the chimney box enters the roof drywall, so if you have to work on the box or chimney you don't end up having to patch and paint. If you can, try using a garden hose in specific areas to see if you can make it leak under controlled conditions

On my chimney pipes there is one section in the middle that is expandable in case someone needed to shorten the chimney a bit. Not sure why that would be necessary if you were buying all new from the manufacturer but I bought all my chimney parts from a dealer who was retiring and needed all he had to get the correct part. Anyways, the adjustable section had a few obvious gaps where wind could possibly blow rain into and up the seam. When I redid the chimney I straightened that seem as best as I could then used clear JB Weld to seal the seam completely. If'n the rain was entering there it isn't any more. I still think the wind is blowing it through the top cap and it is dribbling down between the inner and outer walls of the chimney pipe. I am not worried about it and it barely left a 4" puddle on top of the stove after the last all day rain we had. I will never know for sure but I know it is not leaking at the roof entry.

 

[viking]

What I've done to seal our chimney is to clean the area to be sealed with Acetone, gets any skin oils or other oils off, then I used clear Silicone, it seems to take the heat quite good and doesn't break down, in fact I was rather impressed with how well it does. If Acetone isn't used the Silicone will not bond properly.

 

[INresponse]

What I've done to seal our chimney is to clean the area to be sealed with Acetone, gets any skin oils or other oils off, then I used clear Silicone, it seems to take the heat quite good and doesn't break down, in fact I was rather impressed with how well it does. If Acetone isn't used the Silicone will not bond properly.

When I used the JB Weld on the one seam I cleaned it well before hand. I don't know what I used, maybe acetone or carb cleaner or something else but it was holding strong before I assembled the pieces. I considered sealing the other seams but they fit together pretty snug and there is more than a 2" overlap a solid "thump" connection when they seat together. It's possible 50mph winds could blow the rain up that seem but a normal rainfall shouldn't cause that to happen. The last rain we had was just a steady sprinkle or light rain with maybe 20mph gusts. And by light rain, in the midwest I would say it would compare to a sprinkle. I get excited when we have rain and two drops touch each other on the cement. A sprinkle hear is a mist in the midwest.


When I used the 30 year silicone on the roof around the chimney when I installed it I cleaned everything per the instructions and when I checked that a few months back everything was still solid.

 

[Magus]

I have a stupid but effective and cheap solution.
Presuming your chimney has a cap, if not that might be part of the issue.
go to home depot and buy a 5 gallon metal storage can for 6$
dead center it with a 1/4 inch hole and affix it to your cap with a bolt and a wing nut,
if your pipe is bigger than 8" use a cheap washtub.
you WILL have to re adjust your draft settings to make it draw better.
you might also consider anchoring it to the roof as the larger size will be more vulnerable to blowing off.
Sure, it will look like a mushroom, but you'll save your stove!

 

[INresponse]

I have a stupid but effective and cheap solution.
Presuming your chimney has a cap, if not that might be part of the issue.
go to home depot and buy a 5 gallon metal storage can for 6$
dead center it with a 1/4 inch hole and affix it to your cap with a bolt and a wing nut,
if your pipe is bigger than 8" use a cheap washtub.
you WILL have to re adjust your draft settings to make it draw better.
you might also consider anchoring it to the roof as the larger size will be more vulnerable to blowing off.
Sure, it will look like a mushroom, but you'll save your stove!

The chimney rises about 10 feet over where it enters the roof and we get some pretty good winds here on a regular basis. I think the bucket would catch too much wind. I do have a cap and I was looking at it while I had it down. I could have put a larger piece of sheet metal on the top to give it a bigger umbrella but if the wind is blowing the rain sideway it would still get into the top of the chimney, and if I shaped it into a dome to have it come down on the sides it would catch the wind.
I would like the drip to stop but we don't get a lot of rain here and I like the idea of the chimney not getting blown over. I don't know if I could get replacement parts. I don't remember the name of the company that made the chimney, the store is out of business because I bought it as a closeout item, and he was one of only a few distributors in the USA for the Canadian company. Not only did I get a great price on the parts they were made to the higher Canadian standards for withstanding chimney fires. And, yes, I could buy another brand if this one is destroyed but I like the idea of it not breaking.

I appreciate all the thoughts and advice. I looked it over and did what I could when I rebuilt it a few months ago but hopefully someone else in the future finds all this information helpful so they can either prevent or correct a similar problem.

If anyone else knows a solution that we all overlooked please share it. It may help me and it will be helpful to others. I know sometimes reviving an old thread causes people to hesitate but having all the information in one old thread is better than breaking it up into multiple threads.

 

[havasu]

It's gotta be a non functioning cap or bad/leaking flashing at the roof itself.

 

[INresponse]

It's gotta be a non functioning cap or bad/leaking flashing at the roof itself.

Since it is not leaking at the roof we will go with the cap. It is coming from inside the inner and outer pipes of the chimney. It is the only way it can be getting into the shroud that tucks up to the roof line and comes through the drywall. Absolutely nothing on the plywood roof or insulation or drywall. Not even sign of a single water drop on anything, it just trickles down the black pipe that goes from the stove to the exterior chimney.

 

[Cabin Fever]

Class A chimneys have insulation between the inside and outside chimney walls. If that it where the leak is, it's good chance that the insulation is soaked.

 

[INresponse]

Class A chimneys have insulation between the inside and outside chimney walls. If that it where the leak is, it's good chance that the insulation is soaked.

Perhaps, but I am sure the heat from the fire helps dry it out fairly quick. Hopefully the stainless pipe is good stainless and wont rust, It should be considering the actual retain price.

 

[Cabin Fever]

Perhaps, but I am sure the heat from the fire helps dry it out fairly quick. Hopefully the stainless pipe is good stainless and wont rust, It should be considering the actual retain price.

With a chimney as tall as yours above the roof, I'd be surprised if there was any heat left in the rising smoke.