What is Down Draught?
A down draught is where the wind penetrates the chimney forcing the smoke and fumes down through the chimney and out from the fireplace or stove.
Causes of down draught
Wind moving downwards and into the chimney.
Wind moving across an obstacle such as a taller roof, building, trees / hedges or across a hill or mountain (especially if the dwelling is situated in a valley or depression). When the wind reaches the end of the obstacle, it will veer downwards and if the chimney is lower than the obstacle, the wind will then flow into the chimney.
If the chimney is situated on the windward side of the dwelling and a window or vent is open on the leeward side of the dwelling.
The fireplace or stove is more likely to be affected by a downdraught if there is no bend in the chimney.
The fireplace or stove is more likely to be affected by a down draught if the chimney suffers from a lack of draught.
How the problem manifests:
Smoke puffs intermittently out from the fireplace or stove when it is windy outside.
Soot gets blown down the chimney when a fire is not lighting.
Noticeable movement of the flame (especially when burning oil or gas) Sometimes but not often, the fire can be extinguished.
Fitting an anti-down draught chimney cowl such as a stainless steel Spinner Anti-Down Draught Chimney Cowl or stainless steel Static Anti-Down Draught Chimney Cowl.
Both products are available in terracotta painted stainless steel.