Water in Attic When Burning

[zmildrum]

Hi everyone,

Last year I got a Regency 500 which I burn basically 24/7. I absolutely love it and am slowing building up my 3 year supply of wood.

With that said, I have no intentions of not burning wood in the winter. However, something odd happens in my attic that is quite worrisome.

When I burn it gets my house to a cozy 80 something degrees in my den. My living room is above it and that gets to about 73. Above that is my attic. (Raised ranch)

The issue is, when I burn for extended periods of time, I have either a condensation problem, or wet walls on the interior of my attic...only between approximately 2-3 rafters from the exterior wall where the chimney is located. The rest of the attic and the other side of the attic is dry (except for one wet spot near an old chimney that is no longer in use from the old oil furnace/hot water heater which is likely just the fact that the chimney needs some work on the outside)

One thing to note, I do not get this water problem when using my forced air to heat the home. This leads me to believe it may not be a condensation problem. I have done some research on this, but it is hard to get any answers to my specific situation.

Any insight you guys can provide, or anyone you could suggest I bring into the home to inspect the issue would be amazing. I'm not even sure who to ask about this particular issue for expert help.

Love the forums and read it all the time. You guys seem pretty knowledgeable, though this may be outside of your expertise.

Thanks ahead of time!!

 

[Ashful]

First, are you sure it's not venting at all into the attic? Is this a fully-lined chimney? I can't imagine this is the problem, you'd have mentioned a smoke smell, but it bears askin.

Do you suspect make-up air drawn in to supply the stove could be condensing on cold attic surfaces? If you crack a window near the stove for the entire duration of the burn, does the condensation problem go away?

 

[zmildrum]

First, are you sure it's not venting at all into the attic? Is this a fully-lined chimney? I can't imagine this is the problem, you'd have mentioned a smoke smell, but it bears askin.

Do you suspect make-up air drawn in to supply the stove could be condensing on cold attic surfaces? If you crack a window near the stove for the entire duration of the burn, does the condensation problem go away?

I'm almost 100% it is not venting into the attic. I bought the stove through a reputable company that included installation with a liner. Though I had experiences in the past with less than professional, professionals. However, there is no smoke smell at all so I do not believe this to be the case.

Not sure how the air would be drawn in from the attic or how exactly that would make condensation, but I'm willing to try! On my next burn I will test this out.

 

[EbS-P]

So warm wet air is getting to that spot and condensing on the cold roof. I have no evidence that this is actually happening but it’s what I can offer. I’m guessing you have a air leak in that vicinity that is allowing warm inside air up to the attic. Keeping the den at 80 degrees is probably warmer than you are keeping with the forced air system. So this warm air escapes up to the attic and condenses.

Not for my explanation of why you don’t see it with the forced air system. Duct leakage and the mate some air imbalance is creating a slightly negative pressure near the air leak and drawing cold attic air down.

Again just a guess. Condensation in the attic is never good keep pressing on till you figure it out.

 

[peakbagger]

Assuming 06443 is you zip, you are in CT. That means you can get snow on roof. Any chance that your roof penetration is causing ice damming?. The attic in theory is supposed to be at outside temp but heat radiating from the stove pipe could be heating the area around the pipe to above freezing while the areas at the boundary will still be frozen. Water or melted snow would run down the roof to the boundary and then back up under the shingles and then leak down?. Its stretch

 

[zmildrum]

So warm wet air is getting to that spot and condensing on the cold roof. I have no evidence that this is actually happening but it’s what I can offer. I’m guessing you have a air leak in that vicinity that is allowing warm inside air up to the attic. Keeping the den at 80 degrees is probably warmer than you are keeping with the forced air system. So this warm air escapes up to the attic and condenses.

Not for my explanation of why you don’t see it with the forced air system. Duct leakage and the mate some air imbalance is creating a slightly negative pressure near the air leak and drawing cold attic air down.

Again just a guess. Condensation in the attic is never good keep pressing on till you figure it out.

This sounds the most likely scenario. I did seal up some holes from wires, but there are likely others that aren't sealed well, and I believe the 2x4 directly next to the exterior wall with the chimney on the floor of the attic has no insulation over it at all. I'll try to seal that up good and go from there.

Assuming 06443 is you zip, you are in CT. That means you can get snow on roof. Any chance that your roof penetration is causing ice damming?. The attic in theory is supposed to be at outside temp but heat radiating from the stove pipe could be heating the area around the pipe to above freezing while the areas at the boundary will still be frozen. Water or melted snow would run down the roof to the boundary and then back up under the shingles and then leak down?. Its stretch

This is a good thought, however this also happens when there is no snow at all. The roof is brand new as well, only two years old.

 

[moresnow]

If you have bathroom vent fans? Where are they venting? Is the attic or roof ridge vented? Did this issue start/become noticeable after the new roof? A few things to consider.

 

[stoveliker]

Another thing to test could be to get the den up to 80 F with the oil, i.e. the same temps as with the stove. Air leaks to the attic should then be similar. If the outside temps are similar as when you saw the condensation, it should result in similar condensation with the oil heat.

 

[Highbeam]

The roof is brand new as well, only two years old.

Smoking gun... Was this problem present before the new roof?

Roofers are not always very good regardless of how much you pay them. I really dislike the ones that feel like fast = good. Bang bang bang goes their nail gun as fast as a machine gun which to me means carelessness.

 

[zmildrum]

Smoking gun... Was this problem present before the new roof?

Roofers are not always very good regardless of how much you pay them. I really dislike the ones that feel like fast = good. Bang bang bang goes their nail gun as fast as a machine gun which to me means carelessness.

Unfortunately I am not sure if the problem existed before the new roof. We moved in 2020, go the new roof immediately. I didn't notice a problem until after we had the insert installed. That is not to say the problem didn't exist previously - with moving in and various projects around the house I did not go into the attic that winter basically at all.

Going to make my way to Home Depot today though to get some insulation for the side that looks lacking, and some spray foam to seal up some gaps. Hopefully that will help!

 

[stoveliker]

if it has been going on for longer, the quality of the sheets on the roof will likely be quite a bit worse than in other places (unless you had that sheeting replaced when you put the new roof on)

 

[GrumpyDad]

Hi everyone,

Last year I got a Regency 500 which I burn basically 24/7. I absolutely love it and am slowing building up my 3 year supply of wood.

With that said, I have no intentions of not burning wood in the winter. However, something odd happens in my attic that is quite worrisome.

When I burn it gets my house to a cozy 80 something degrees in my den. My living room is above it and that gets to about 73. Above that is my attic. (Raised ranch)

The issue is, when I burn for extended periods of time, I have either a condensation problem, or wet walls on the interior of my attic...only between approximately 2-3 rafters from the exterior wall where the chimney is located. The rest of the attic and the other side of the attic is dry (except for one wet spot near an old chimney that is no longer in use from the old oil furnace/hot water heater which is likely just the fact that the chimney needs some work on the outside)

One thing to note, I do not get this water problem when using my forced air to heat the home. This leads me to believe it may not be a condensation problem. I have done some research on this, but it is hard to get any answers to my specific situation.

Any insight you guys can provide, or anyone you could suggest I bring into the home to inspect the issue would be amazing. I'm not even sure who to ask about this particular issue for expert help.

Love the forums and read it all the time. You guys seem pretty knowledgeable, though this may be outside of your expertise.

Thanks ahead of time!!

That's interesting that it happens only when you heat with your stove.
Curious you said you get wet walls then mentioned rafters, so Im assuming you are talking about your roof ceiling not the walls in that 'room'. Is it toward the outside of the house or more toward the peak of the house?

Last winter when I was checking out for potential areas to exit with my wood burning stove, looking for wires, as I pulled insulation down I noticed it was damp and that the plastic baffles that help move air from the outside soffit to the roof center ridge vent were damp as well. I asked a friend who runs a sizable construction crew that does roofing, and he said it sounds like everything was done right, such as the soffit vents leading up through baffles that provide 1" of air flow to the roof vent. The roof vent may need a bit more opening though. So I checked it out up there and the plywood in the center there is only about a 1" gap to the roof vent. Im not sure if that's enough air flow. Subsequent checks I didnt see much moisture throughout the year. The only time I would is if I let that are cool down significantly then get it really hot fairly quickly (like within the same day).

So what you might be experiencing is much like me. Insufficient size for air to flow at the ridge / roof vent, and a sudden heat up of that space that you dont otherwise get using conventional as that is probably not a conditioned space using conventional whereas your chimney pipe is heating it up when stove in use. Shrug.

 

[peakbagger]

That's interesting that it happens only when you heat with your stove.
Curious you said you get wet walls then mentioned rafters, so Im assuming you are talking about your roof ceiling not the walls in that 'room'. Is it toward the outside of the house or more toward the peak of the house?

Last winter when I was checking out for potential areas to exit with my wood burning stove, looking for wires, as I pulled insulation down I noticed it was damp and that the plastic baffles that help move air from the outside soffit to the roof center ridge vent were damp as well. I asked a friend who runs a sizable construction crew that does roofing, and he said it sounds like everything was done right, such as the soffit vents leading up through baffles that provide 1" of air flow to the roof vent. The roof vent may need a bit more opening though. So I checked it out up there and the plywood in the center there is only about a 1" gap to the roof vent. Im not sure if that's enough air flow. Subsequent checks I didnt see much moisture throughout the year. The only time I would is if I let that are cool down significantly then get it really hot fairly quickly (like within the same day).

So what you might be experiencing is much like me. Insufficient size for air to flow at the ridge / roof vent, and a sudden heat up of that space that you dont otherwise get using conventional as that is probably not a conditioned space using conventional whereas your chimney pipe is heating it up when stove in use. Shrug.

There is known problem with vented ridge pole systems in areas with snow. The snow caps over the ridge vent and short circuits flow up through the soffits until it melts. Properly sized gable end vents under overhangs do not have the same issue but can have an issue with fine snow blowing in through the louvers during blizzard type events. The solution to that is to install a large collection tray inside the gable end vent to catch that sugar snow before it gets on the insulation and melts.

 

[rwhite]

I'll go through the standard liner questions: is the liner insulated?, Did you install a block off plate? , How's the chimney crown look? Not a lot of installation details but you did mention a liner. If this is in a chimney, it sounds like your driving moisture out of the bricks due to a heat differential and your ceiling is not insulated enough to keep warm air out, and attic is not vented well enough to pull it out.

 

[30WCF]

If your house is like mine, the attic is not sealed around the masonry chimney. I have a couple inches of gap between the brick and the attic floor. I can look down the brick and see the crawl space below the main floor. This is from an old oil furnace and not used anymore. Is the brick below heating with the stove and you have a draft rising right along the chimney and coming up between the chimney and attic floor right at the colder brick?
Get a little windicator puffer from the hunting section and go puffing it around the attic I’m suspect areas.

 

[gzecc]

Your attic is getting too warm. Probably poor insulation. Add loose cellulose to potentially seal any air leaks coming from the lower floor.

 

[Ashful]

Your attic is getting too warm. Probably poor insulation. Add loose cellulose to potentially seal any air leaks coming from the lower floor.

This doesn't make sense to me, gzecc. I don't think it's an issue of the attic getting too warm, I think you're conflating "getting warm" with "receiving too much moist air from the living space".

In general, aside from any specific and unusual issue the OP is experiencing, moisture carried out of the warm living space can hit a cold surface in the attic, say the underside of your roof sheathing, and condense. I guess you might equate that with the "attic getting too warm", but that's equating effect with effect, rather than cause with effect.

 

[stoveliker]

The point that appears to have been forgotten is that the moisture was only on two sections (between three rafters) if I remember correctly.

That indicates it's not a whole space issue, but localized source. (Leaks of warm moist air.)

Gzecc does have a point that if (in winter) the attic would remain at the same temp as outside, it's unlikely condensation would happen. As such, the attic is too warm, and moisture input is localized.

 

[GrumpyDad]

The point that appears to have been forgotten is that the moisture was only on two sections (between three rafters) if I remember correctly.

That indicates it's not a whole space issue, but localized source. (Leaks of warm moist air.)

Gzecc does have a point that if (in winter) the attic would remain at the same temp as outside, it's unlikely condensation would happen. As such, the attic is too warm, and moisture input is localized.

When I first arrive at my cabin and crank up the heat then feel the plastic baffles under the insulation, it's damp. However, subsequent days it is not. And this doesnt always happen. I dont know why, and a roofer I know said there isnt much I can do about it. In fact he isnt a fan of using the coded method of using plastic baffles from the soffit to the ridge vent for this very purpose, because now that moisture needs to go somewhere and it will do so slowly. Im not worried about the insulation as much as I am the rafters that they touch on the edges where they are damp. It might take 20 years for those rafters to even see a mark on them from this, but maybe only another 20 more for those to rot. So I think my goal going forward which will help for the summer as well, is to moisture control this building.

Now what happens when we are living in this space, cooking etc - I dont know. That's alot of moisture evaporating upwards eventually meeting the cold roof deck

 

[stoveliker]

But I was not talking about your attic; I was noting that the OP only saw 2-3 rafters wet.

In your case, there should not be baffles from the soffit (all the way to) the ridge vent.
But roofers do not know much about insulation and moisture issues, imo. I would not trust a roofer to give proper (engineering) advice on climate control.

 

[GrumpyDad]

But I was not talking about your attic; I was noting that the OP only saw 2-3 rafters wet.

In your case, there should not be baffles from the soffit (all the way to) the ridge vent.
But roofers do not know much about insulation and moisture issues, imo. I would not trust a roofer to give proper (engineering) advice on climate control.

Oh it's code in my area. Block the top plate to roof deck up to the first baffle then baffle all the way to the ridge vent. And the wizards that came up with these products, didnt think to make it so that you could staple the baffles to the rafters with wings. Nope, you staple it to the roof deck. Then you insulate over this.
It ensures a proper 1" airflow chamber is retained.

 

[zmildrum]

Hi everyone, thank you all for the suggestions. With the recent record heat in my area, I haven't needed to run the fireplace! I bought some more insulation to lay out and cover some gaps in the attic but haven't had the opportunity to light it up yet. Tonight might be the night!

If your house is like mine, the attic is not sealed around the masonry chimney. I have a couple inches of gap between the brick and the attic floor. I can look down the brick and see the crawl space below the main floor. This is from an old oil furnace and not used anymore. Is the brick below heating with the stove and you have a draft rising right along the chimney and coming up between the chimney and attic floor right at the colder brick?
Get a little windicator puffer from the hunting section and go puffing it around the attic I’m suspect areas.

I too have that gap around the old chimney that used to exhaust the oil fired burner - this is no longer in use. I have sealed up that gap a bit, but I do get some moisture around this chimney as well. This happens with or without the fire, so I'm inclined to think that once this is fully sealed up it should resolve itself.

Something else could be in play here for me. I have a sunroom along the backside of this part of the house with the problem. This has removed some of the soffits. I will also pull back some of the insulation near the soffits as there isn't a huge gap between the insulation and the underside of the roof. I can see some daylight, but very little. Any idea how much of a gap there should be between the insulation and the underside of the roof? I think there is about an inch or two in some places, if that.

 

[peakbagger]

As long as there is clear channel for cold air to flow up under the roof from the soffit to the ridge vent you are covered. I have seen people rip strapping or spare sheathing into 1-1/2" wide, screw them up under the sheathing and then lay 1/2" iso board foam up against it. and it works as the foam keeps heat from the house (usually from the poorly insulated area at the top of the wall from getting up into the roof sheathing. If that area is warm and there is snow on the roof its the beginning of ice dams. The commercial "proper" vents are just flimsy open cell foam that maintain about a 1.5" gap but most of them are sized for 12" roof joist spacing. Double them up for 2" roof joists but i someone has 16" joist spacing like in lot of Northeast they just use the 12" versions so the airflow is restricted.

 

[mellow]

Wouldn't insulation just trap the moisture on the wood? I would think spray foam or sealant would be best used to seal that up.

 

[EbS-P]

Oh it's code in my area. Block the top plate to roof deck up to the first baffle then baffle all the way to the ridge vent. And the wizards that came up with these products, didnt think to make it so that you could staple the baffles to the rafters with wings. Nope, you staple it to the roof deck. Then you insulate over this.
It ensures a proper 1" airflow chamber is retained.

That only makes sense if you are trying to insulate the roof decking and that only makes sense to me if you are trying to encapsulate the attic. and if one does that every rafter bay gets a vent and baffle and insulation. Radiant barrier sure stable that to the bottom of the rafters.