Cowls and Terminals

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Every day I encounter opportunities with cowls and terminals. The following information is provided to help understanding regarding these. Specifically around which ones are not appropriate for live appliances/ fires.

My concern is the safety of your chimney/ flue. The terminal or top of your chimney plays an important role in the overall system. These include pots, cowls, bird guards etc.


There are many designs. It may be due to location, weather, vermin etc that it is necessary to fit a guard or cowl. 

Many terminals are not designed for use with a live appliance/ fire. They do not conform to building regulations for live chimneys and can cause problems when used with solid fuel. Unfortunately they are often fitted, unaware of the regulations and dangers. Further, many terminals are incorrectly fitted. They prevent sweeping through the pot and or risk being dislodged.


The ones below must NEVER be used for a live appliance/ fire. They are for unused / decommissioned chimneys only.



These guards are a cheap alternative to a bird guard. The mesh size is small and this reduces the flow of gasses. They soon become blocked. They are not secure so your sweep will either not clean the pot (sometimes the dirtiest part) or it gets pushed off the top or the sweep gets his brush tangled up in it and a bigger job evolves. 
It will not keep rain out.  They corrode and fall in to the chimney, providing a danger with increased risk of fire. Advisable to replace it with a proper guard with strap fittings. Depends on the situation, perhaps something like this, made from stainless steel:


Cone insert

These guards have the same problems as the one above. Birds squeeze through them and rain will ingress into the chimney. Again it is not normally secured and again it can corrode and fall in to the chimney. 


Half pipe insert

These typically have Not for Live engraved on the top. In this picture we can see why, with the half pipe dangerously clogged up.

Click your mouse over the image to right to magnify

the stamp on top of the insert.

Gas insert

Clogged up from being used on a Wood burning Stove!