Fixing downdraft issues
An exposed chimney cools the flue gases rapidly and the draft is never as good as it is in a well protected flue. If the fire has been out for some time, the chimney draft may well be reduced sufficiently to cause smokiness in the room. If the fireplace is never used, this will result in a cold draft entering the room.
Uninsulated cast-iron or other single wall flue pipes should never be used outside a house as a chimney. The severe chilling of the flue gases, particularly when an appliance is burning slowly, not only results in unsightly condensation but more seriously reduces the flue draft so much that dangerous fumes may be emitted from the appliance because there is little or no draft to carry them away.
Chimney tops in a high-pressure region of high wind pressure can produce smoke emission into a room by preventing the updraft, or if the pressure is high enough it causes a downdraft. This is where there is a low pressure (suction) on one side of the house. This can be created by trees or taller buildings being near by. ther examples are found when the house is at the top of a hill or at the bottom of a hill.
To fix these we would use a range of products including an anti-downdraft cowl, a spinning cowl or a cap for fires that are not used. Chimney balloons are used at the bottom of the opening to stop these issues - these are great as they allow a small amount of air to pass around the corners to keep the chimney flue ventilated.
We make hoods to help reduce the opening and increase the draw of open fireplaces and stop smoke spillage occurring.