Cowls for Brick Braais

What a cowl does and does not do

A cowl prevents downdraughts and stops rain running down the chimney. It does not make a badly designed chimney draw. A correctly built chimney should draw on its own; the cowl then protects it from wind and weather.

How to choose the right size

• Sizes such as 400 x 400 mm are the cowl's inside base opening, not its outside footprint.
• Measure the inside width and depth of the brick chimney opening. The cowl opening must be equal to or larger than both measurements; it may never be smaller.
• Choose the closest standard size that covers both measurements. A rectangular cowl can be turned to suit the chimney. Avoid a cowl that is much bigger than the opening.
• Measure the outside of the chimney as well. Standard cowls have a 75 mm flange all round, so the outside footprint is the opening plus 150 mm (for example 550 x 550 mm for a 400 x 400 mm cowl). That footprint must be at least 20 mm smaller than the outside width and depth of the chimney, so the flange sits fully on the brickwork.
• For an odd-sized chimney, the custom turbo cowl page has a calculator for mild steel cowls from 280 x 280 mm up to 1200 x 1200 mm. Custom sizes in stainless steel are quoted on request: send the inside and outside chimney measurements and the steel grade you want.

Cowls for a new built-in braai

Standard mild steel built-in braais in 800, 1000 and 1200 mm already come with two flue sections and a turbo cowl. Stainless steel built-in braais and the larger models list their flue and cowl separately; the matching size is shown on each braai's product page.

Choosing the material

A cowl sits on top of the chimney, fully exposed to wind, rain and salt air, even when the braai or fireplace itself is indoors. Choose the grade for an outdoor installation:

• Coastal towns such as Cape Town, Durban or Knysna: 316 stainless steel is the recommended grade; 316 cowls are always made to order. 304 stainless steel is the lower-cost alternative. Do not use mild steel or 430 at the coast.
• Inland towns in a coastal province, such as George or Stellenbosch: 304 stainless steel.
• Inland areas such as Johannesburg, Pretoria and Bloemfontein: 430 or 304 stainless steel. Mild steel (sprayed black) is the budget option, suitable for drier inland conditions. 316 is suitable anywhere but is not normally needed inland.

See the steel grade and installation environment guide for more detail.