Chimney Condensation

[Amy P]

Hello all. I wasn't sure what forum to post this in or if it is even ok to ask questions here. I live in Ohio in a home built in 1913. I have had horrible problems with what I think is condensation right at the ceiling/wall line on the second story at my chimney line. Only happens in the summer and only in high humidity. I have typed out everything I have tried. I am at a loss !

Nothing appears to be leaking in the attic even upon heavy rain. Condensation/water only around wall/ceiling at chimney wear it meets second story ceiling from attic to second story ceiling/ wall.

2012 – New HVAC with AC installed late in season. AC rarely used if at all. No condensation or water on ceiling/wall.

2013 – Summer season started to notice wall getting some condensation/wetness. Nothing done. Fall through spring no problem. Wall/ceiling dry.

2014- Summer season noticed wall getting some condensation/wetness again. Attic checked no apparent leak coming through roof, even upon heavy rain. Had chimney above roof line sealed on outside and around roof line. This was late in the season and the wall started to dry. Fall through spring no problem. Wall/ceiling dry.

2015 – Summer season started to notice wall getting wet again and now into ceiling. July 2015 took chimney off to below roof line. Put up B vent and liner in chimney. Water heater and furnace routed through that liner and B vent. End of season wall/ceiling dried out. Fall through spring no problem. Wall/ceiling dry.

2016-2019 – Every summer season wall/ceiling would get wet and then dry totally in the winter through spring. Looked for leaks in attic/roof. Nothing else done.

2019 – Summer season very wet wall/ceiling did the below

Put in roof vents, 2 gable vents, wrapped chimney in attic with insulation, changed any old pipes in basement, mortared in spot that was open in basement to chimney and in kitchen where old stove pipe was from many years ago. Knocked out a part of wall where it was really wet in wall. Totally dry under it and chimney brick dry. Looked in attic again no active leak. Condensation/wetness in wall ceiling seem to be worse. At the very least no change.

 

[Kevin Weis]

It's from the air conditioning (cool air) hitting the warmer parts of chimney. Had this happen to my stove this summer. All inside developed condensation, inside of glass and all interior parts of the stove. Think the main cause of it was the super high humidity with the heat. We had humidity here above 80% and above 90 degrees air temperature. With the humidity gone and even though above 90 I didn't have the condensation with the air on. No sure there would be anything you can really do about it.

 

[Sawset]

What are the air conditioned room temperatures.

Maybe related:
I was on a contract hvac job once in a cheese plant. Just the opposite problem - cheese curds brewing below, extreme high humidity inside, January temps outside. I'm not sure if I've ever seen so much condensation in the attic areas. Water dripping everywhere. Nice idea to have a cheese outlet in a nice old building, but man were they ill equipped for that.

More likely:
A roof leak that's real difficult to trace might be another thing to keep investigating. Sometimes they can travel a long way, or occur only under certain conditions like wind direction etc. Stuff dries up but the damage is done. And the heat and or lack of rain in winter reduces it all.

 

[Amy P]

What are the air conditioned room temperatures.

Maybe related:
I was on a contract hvac job once in a cheese plant. Just the opposite problem - cheese curds brewing below, extreme high humidity inside, January temps outside. I'm not sure if I've ever seen so much condensation in the attic areas. Water dripping everywhere. Nice idea to have a cheese outlet in a nice old building, but man were they ill equipped for that.

More likely:
A roof leak that's real difficult to trace might be another thing to keep investigating. Sometimes they can travel a long way, or occur only under certain conditions like wind direction etc. Stuff dries up but the damage is done. And the heat and or lack of rain in winter reduces it all.

Thank you for your response. Lately I have been doing some construction in the house so I have been leaving the air conditioning either off or at like 78. The thing is this only happens upon high humidity. It doesn't really seem to matter if it is raining or not. It needs to be summer ish weather and humid. I'm repairing all my old plaster walls, priming/painting , etc. I can't get any further in that hall way until I figure that problem out once and for all or it will just be ruined by next summer. This is like one of those problems that no one can seem to figure out and it really has me, my contractor and everyone I know perplexed. Hmmmmm.

 

[kennyp2339]

Its the opposite effect, the chimney is cooler and the hot humid weather in the attic area creates surface moisture by condensing, I'd wrap the chimney with insulated foil wrap with aluminum tape to keep the air from condensing on it then dripping down and ruining your walls and ceiling. Also do the roof vents have the auto fan built in them, or are they the static type? how well is the attic insulated? you could be forcing the extra water vapor from the living space into the attic from the AC since cool air is more dense (holds less moisture)

 

[Amy P]

Its the opposite effect, the chimney is cooler and the hot humid weather in the attic area creates surface moisture by condensing, I'd wrap the chimney with insulated foil wrap with aluminum tape to keep the air from condensing on it then dripping down and ruining your walls and ceiling. Also do the roof vents have the auto fan built in them, or are they the static type? how well is the attic insulated? you could be forcing the extra water vapor from the living space into the attic from the AC since cool air is more dense (holds less moisture)

Thank you for your response. The roof fans do not have an auto fan. No electric up there but that is not out of the question I suppose. I did have the chimney wrapped with insulation. I think they just used regular house insulation. To be honest I haven't crawled up in that attic space and looked again. That chimney is not necessarily being used for anything. It has a liner and a b vent running through it. I have had someone tell me to just take the chimney down below the ceiling line in that second story. Thoughts ?

 

[spudman99]

Attic fans can be had with solar power which might negate running electricity. Pricier but remain an option. Focus on trying to separate the chimney from the attic air, using insulation as noted above and more air movement. That of course assumes there is no roof leak or penetration.