In certain conditions, this is enough to send the smoke right down to the ground where it can become a nuisance. The stealthy design promotes maximum aerodynamic efficiency in dealing with downdraught and smoke blow back, whilst the shape gives maximum protection against driving rain. This is the cause of the commonly-seen defect where the top few brick courses of the stack are falling apart, or where a stack is leaning due to acid-induced swelling of the mortar on one side.

Additionally, MAD Cowls offer chimney liner cowls, redundant chimney caps as well as spinning cowls made from a thick aluminium cast base with a stainless steel fin set and shaft assembly. With the emergence of eastern countries as a source of cheap product within the chimney cowl sector, in 2005 it was time for the Burford family using the brand name M.

For over 80 years Colt Cowls have been supplying the UK market with chimney cowls and can therefore boast the most experience in designing and producing chimney cowls. A.D cowl brand is a trade name of J D Burford Ltd, our family business is involved in a variety of sectors born from our main capabilities of metal spinning, metal forming and metal finishing.

No cowl can be guaranteed to cure all types of downdraught as the causes are so varied, but tests and observations have shown that the Aderyn cowl is one of the best at doing exactly that because unfavourable downward air flows are split by the cowl and directed over each side of the pot, and the low pressure zone just above the pot is pre-served, maintaining chimney function.MAD Cowls is also known for their range of bird guards to alleviate the nuisance of birds, small animals, and leaves entering the chimney. I would also question why they are not made with 1" square mesh to allow the bird guard to remain fitted for solid fuel appliances. Because the Aderyn cowl faces away from any wind, a low pressure zone is created on the lee side just above the chimney pot. To work properly a chimney must have draw, both to clear the products of combustion and to provide fresh combustion air to the fire.