Weird Condensation

[Blacksails]

Hey guys.

First post and brand new to stoves. I’ve just moved into a cabin that came with a wood stove. I don’t know the make and model and can’t find a makers mark or information on it anywhere. I’ve been burning wood and duraflame logs.

A few nights ago I noticed some water on the floor behind the stove, then again this morning I noticed some after waking up (Fire was burning the night before).
I’ve been upstairs and the point at which the flue goes through the roof is where it’s dripping from. There is a wooden plate on the ceiling that the flue goes through, which is sealed around the edge with black silicone. This silicone has pealed back and the water is dripping from there.
It doesn’t drip from rain, so I think a standard roof leak can be ruled out at this point. It is, however, starting to get cold outside here in Iceland at the moment. Beginning to have frosts in the morning and on the roof.

Any opinions on what might be wrong and how I can stop this? Obviously resealing the edge with silicone is an option, but then that means the issue is still there and will just be trapped inside the roof.

pics attached

 

[Highbeam]

Is it black or stinky like smoke?

 

[Blacksails]

Is it black or stinky like smoke?

Nope, clear and no odour. Just water

 

[Highbeam]

Clean water is either from rain or from condensation in your roof/ceiling system. I would wager that your roof flashing is the culprit. Looks like a steep roof. Even professional roofers do some hokey work on roof flashings.

The silicone on the inside and the evidence of water stains tells us that this is not a new problem

 

[begreen]

Is there a metal roof flashing on the chimney? If so, does it have a rubber or silicone boot?

 

[Blacksails]

Is there a metal roof flashing on the chimney? If so, does it have a rubber or silicone boot?

I’m not at the cabin right now to check, but the roof is corrugated sheet steel. On the outside around the chimney is a large square flat piece of metal but I’m unsure what you mean by a rubber boot.

It can rain or snow and there is no leak, but if the stove has been burning, even on a dry cold day, I will get these drips. It seems to not happen if I get the stove very hot.

 

[Blacksails]

Clean water is either from rain or from condensation in your roof/ceiling system. I would wager that your roof flashing is the culprit. Looks like a steep roof. Even professional roofers do some hokey work on roof flashings.

The silicone on the inside and the evidence of water stains tells us that this is not a new problem

Definitely not from rain. We’ve had some really bad rain and wind storms, as well as snow sitting on the roof and it hasn’t leaked. But if I have the stove on and it seems that if I don’t get it burning hot, even in a dry day, it’ll drip.

I’m quite handy, although I’ve never touched a roof. Is flashing something I could tackle myself? Obviously given that all safety precautions are taken being up there.

It’s been cold all day today. Was dripping this morning. I got the flue really hot and it didn’t drip again all day.

 

[Highbeam]

The interior source of clean water dripping is condensation. Warm moist interior air hitting something cold and the water condenses out like on a cold beverage or even a toilet tank. The bottom of your chimney can be cold like this. I’ve had puddles under cold toilet tanks that are several inches across.

I don’t know how you can fix this except to reduce interior humidity.

 

[begreen]

I’m not at the cabin right now to check, but the roof is corrugated sheet steel. On the outside around the chimney is a large square flat piece of metal but I’m unsure what you mean by a rubber boot.

It can rain or snow and there is no leak, but if the stove has been burning, even on a dry cold day, I will get these drips. It seems to not happen if I get the stove very hot.

What I am wondering and concerned about is that water is accumulating in the ceiling support due to bad flashing. And that is what is causing the sweats. If you can post a good picture of the flashing where the chimney comes out of the roof we may be able to spot something. I could just be condensation from the cold surface, but it's good to check it out.

 

[Highbeam]

When you come to your cold weekend cabin and heat it up, cold things sweat until everything gets warm. This is a common problem in mechanic shops where tools will rust from condensation. I’ve had tractors dripping water from their iron engines.

I’ve even seen cold concrete slabs sweat when the air is warmed.

How cold are you letting the cabin get between visits?

 

[Blacksails]

What I am wondering and concerned about is that water is accumulating in the ceiling support due to bad flashing. And that is what is causing the sweats. If you can post a good picture of the flashing where the chimney comes out of the roof we may be able to spot something. I could just be condensation from the cold surface, but it's good to check it out.

I’ll get a photo this week and upload it here. It leaks down from the silicone seal, so it’s definitely coming from inside the roof And I am concerned. My hope is that it’s just a few drops of condensate from further up the flue where it’s a bit cold. For example this morning, there was a few drips on the floor after the fire had burnt the night before. Then a heavy frost set in over night and settled on the roof. Seems like a recipe for condensation but, I’m a deeply paranoid man. Still, if it is condensation, I’d prefer to try and stem it a bit.

 

[Blacksails]

When you come to your cold weekend cabin and heat it up, cold things sweat until everything gets warm. This is a common problem in mechanic shops where tools will rust from condensation. I’ve had tractors dripping water from their iron engines.

I’ve even seen cold concrete slabs sweat when the air is warmed.

How cold are you letting the cabin get between visits?

I’m hoping it is just a bit of condensation. It would make sense as rain doesn’t come through. We are in the slow process of moving there. By the end of this month we will be there full time. It had been empty for two or three days previous to this weekend. We did leave the radiators on low, so the house wasn’t freezing but it wasn’t warm.

 

[Blacksails]

Ok, so there have been quite a few developments.
I made a set of locking ladders to get up onto the roof and you guys were right. Flashing.
It looks ******* awful. There are standard wood screws driven into it in one part of the flashing that is bulging. Huge crack (not visible in photos) up the one edge.
The woman we are buying off of wants to send her carpenter over to make a repair, but to me this looks like the whole outside chimney just needs to come out and be replaced. What do you guys think? Is that roofing cement that’s caked everywhere?For the time being I’ve taped over the seams with flashing tape.

 

[mar13]

A bit of off topic curiousity. I see that you have Iceland as your location. In my mind, I don't imagine Iceland having much, if any, in the way of forests and inexpensive wood. (I imagine geothermal.) What do you feed your wood stove and from where do you source it?

 

[Blacksails]

A bit of off topic curiousity. I see that you have Iceland as your location. In my mind, I don't imagine Iceland having much, if any, in the way of forests and inexpensive wood. (I imagine geothermal.) What do you feed your wood stove and from where do you source it?

There used to be a lot of trees and forests, but the vikings cut down a lot of it. Now there isn’t much, but there are active replanting programs.
I’ve personally been buying bags of seasoned wood. It’s about 2000isk per bag. But that’s just because I’m brand new to stoves and have no stock of my own. There are plenty of places that you can find it though. None natural. I build sets at a theatre, so any off cuts I put to the side and have started to build a little pile to season.

 

[rwhite]

I suspect the entire thing needs re-flashed. I cant see the uphill side of the flashing to see if it is tucked under properly. I agree with others that it is likely roof condensation.

 

[Blacksails]

I suspect the entire thing needs re-flashed. I cant see the uphill side of the flashing to see if it is tucked under properly. I agree with others that it is likely roof condensation.

I was convinced it was condensation until we had a storm the other night and wind was driving the rain in. It was literally running.

 

[Highbeam]

It does look bad but also nothing like how we flash a chimney in America so I don’t know how to fix it or if the local custom would just be a new version of the same thing.

 

[Blacksails]

Ok, so I put flashing tape around the edges of the flashing In the hopes of stopping rain driving in during storms. So hopefully that’s the one leak sorted until summer when I can do it properly.

Last night it was -10° but very dry. No ice on the roof.
This morning I fired up the stove and after about 20 minutes I heard the sudden patter/splash of many drips. Like something in the roof had filled to capacity and finally spilled over. Like the small spillage from a cup. Since that initial “overflow” there had been a fairly consistent drip that is slowing as the fire stays on for longer.
So this does again sound like condensation... but what can be done to combat this? We are living in the cabin full time now so the house is not cooling and warming up as much as it was when we were here for a few days then away, but the living room does get cold overnight.
I’m puzzled as to what would be “filling up” with water/condensation on the inside lower edge of the chimney.
I’ve tried to remove the register plate (i think? The plate attached to the ceiling that the pipe goes through) but it’s seriously glued/siliconed on there.

 

[Blacksails]

More pics and top removed. Insulation inside chimney is dry