Chimney Sweating In Attic

A condensation effect also can happen within the chimney itself.

Chimney sweating in attic.

Leaks in the chimney structure. When a fire is started the new warm air moving into the chimney comes into contact with the cold chimney walls causing condensation. That s why condensation is forming on the brick. Code requires a chimney have a cricket if it is thirty inches or wider.

Over time this acidic moisture can do serious damage to your chimney and masonry work but that s not the worst of it. If you see water entry in the attic on the uphill side of the chimney we know a chimney cricket is needed so water is not ponding in this area. The wetness is more severe at the basement and or the first floor than the second floor or the roof. You need more ventilation in the attic and more insulation in the floor of the attic.

Since the entire height of the chimney in the kneewall area about 3 ft was wet we began to think of the chimney as a giant wick conducting moisture from its source wherever that was to most other regions of the chimney. 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. When the warm air of the house comes into contact with the cold wall that separates the living space from the chimney water from the air will condense onto the wall s surface. If left untreated it can damage critical structural elements of the home such as the trusses and rafters ruin insulation damage any stored belongings and lead to the formation of potentially toxic black mold.

The bricks go up around the tile flue liners but at the top you need something to stop the rain and snow from just falling in around the tiles. Condensation in the attic is a serious problem that must be addressed by homeowners. Often ponding water will rust a hole in the simple flashing found on most chimneys. White and tan mineral deposits on the surface of the chimney plaster or drywall.

Sweating as a result of condensation step 1 if the air inside the home is warm and humid and the walls of the chimney are cold this can result in sweating. The pattern of wetness is relatively uniform on all the sides of the chimney exposed in the attic. The sweating in this case is normal and will cease once a fire is built and the chimney heats up. Also there was a fair amount of wet sandy mortar on top of the attic insulation adjacent to the chimney indicating that the mortar was deteriorating.

You can see that the very purpose of the chimney crown is to keep rain out. You can prevent these problems from occurring by maintaining a dry attic with a low relative. Up the chimney the gas going up the chimney or exhaust pipe includes a large quantity of water vapor.