Concrete static chimney cowl Superior, 4 bevelled sides

Superior static cowl in concrete with 4 chamfered sides, the Flemish bemalkap for a freestanding flue from 15 x 15 to 40 x 40 cm or rectangular to 20 x 40 cm. This is the standard version: no side is straight, so the cowl has the same shape all round.

It consists of a base ring, two profiled intermediate rings and an open crown with bird mesh and deflector, in natural grey concrete. The rings turn rising wind, side wind and downdraught into negative pressure above the flue outlet. The draught stays stable and flue gases do not blow back, whatever the wind direction. There are no moving parts and no power supply.

You choose the type by the internal size of the flue. Each flue gets its own cowl, sized to that flue. If flues sit against each other, you need a version with one or two straight sides.

The cowl is dry-stacked on a clean, flat chimney top. Stagger the rings so that the crown finishes level.

Which type fits my chimney? Measure the internal size of the flue. A 20 x 20 cm flue takes type 1A, which measures 42 x 42 cm externally. Check that this external size fits on the chimney top.

Is a bemalkap the same as a static cowl? Yes. Bemalkap, bemal and tiratrek are Flemish names for a static cowl. It is also called an anti-downdraught cowl or chimney cowl.

Does the cowl need maintenance? No. It has no moving parts and works without an electrical supply.