Why is smoke coming back down my chimney?
There are different reasons why your chimney may smoke. Below is a list of the major causes. It may be that only one or a combination of any of them could cause the smoke to blow back into the room.
Blocked chimneys
Solution- Having the chimney swept will either correct the problem or highlight where and what the blockage could be. We can advise on what work will then be necessary.
Cold air up the chimney
Solution- if the fire hasn’t been lit for a while, the air up the chimney can get cold. Cold air is heavy and if the flue isn’t heated quickly enough, the cold air will force the smoke back into the room. Initially, just burn newspaper as this will create a lot of heat quickly and will move the air upwards.
Downdraught
Solution- downdraught is a brief flow of air down the chimney resulting in puffs of smoke interfering with the wind flow. To help with this problem, a cowl can be fitted on the pot. It is advisable to ask your chimney sweep which type of cowl to use as there are many different designs suited for the different problems. If the incorrect cowl is fitted, it may make the problem worse being pushed back into the room. One reason for downdraught is that the chimney stack has been built to short and another could be trees, buildings or other large high objects.
Inadequate ventilation
Solution- all fires need air to make them burn properly. A lot of properties are very well insulated with double glazing etc. thus not allowing a flow of replacement air into the room. This can be solved by fitting air vents or simply leaving the door to the room open.
The wrong type of cowl fitted on the top of the pot
Solution- many people are ill advised as to the correct type of cowl to fit. Fitting the wrong type can either cause the problem or make it worse. We can advise as to whether you have the right cowl fitted.
The wrong sized fireplace
Solution- in the uk, the average size fireplace opening is about 18″ wide and 24″ high. If it exceeds this by a large amount, some of the smoke may curl out into the room. Try either lifting the grate up or lowering the height.