Chimney Condensation In Attic

The walls of the chimney can take time to warm up so when a new fire is lit the hot exhaust air from the fire will come into contact with the cold walls of the chimney and condensation will occur.

Chimney condensation in attic.

Condensation can also occur within the chimney. The wetness is more severe at the basement and or the first floor than the second floor or the roof. Another event that could happen although i have never heard of it actually happening is that you could get so much moisture in your attic that it could condense and roll down the stringer onto your chimney. The pattern of wetness is relatively uniform on all the sides of the chimney exposed in the attic.

Normal amounts of humidity and moisture in the hot air condense inside your chimney as the air cools leaving water which can be as acidic as bleach. A flue that is too large allows too much air to circulate making it difficult for the warm gas and vapors exiting the furnace to create a strong updraft up and out of the vent. Condensation of exhaust gases are evidenced or accompanied by one or more of the following. In the attic a kneewall blocked observation of the chimney.

The new decking was mostly dry except for droplets of moisture apparently condensate not leakage from the roof on a few nails. In early january we cut an access to observe the chimney and the underside of the roof deck. However the chimney was a different story. Over time this acidic moisture can do serious damage to your chimney and masonry work but that s not the worst of it.

It has happened and usually isn t discovered until people have spent a terrible sum fixing everything else. There may be damp patches on the chimney breast or the ceiling above it or possibly the walls around it. When a fire is started the new warm air moving into the chimney comes into contact with the cold chimney walls causing condensation. You might also see staining or discolouration in these areas.