Isis Chimney Care A member of The Guild of Master Chimney Sweeps Cowls 01793 745 553 07729 834 864 Or email; Cowls Are fitted for a number of reasons mainly: : To stop birds and squirrels from blocking your flues with nesting material : Prevent  the ingress of rain in redundant flues : Controlling the amount of air a redundant flue draws out of a house (up to 60 cubic metres and hour!) : Solving downdraft problems : To improve draw Beware not all cowls out there are suitable for solid fuel! And some fixing methods are just not strong enough! Isis chimney care can provide free advice, supply and fit   Square birdguard made in England by Brewer Ultimate Flue Outlet made in England by Brewer Chimney Capper made in England by Brewer Aspirator revolving cowl, made in England by Brewer