There are many reasons for fitting Cowls, Caps or a Guards to the chimney pot, and a large variety of products available.
Many people fit guards to prevent birds entering the chimney and nesting. Many chimneys get blocked because of this.
Disused chimneys can cause problems and capping them should due seriously considered. This prevents rain coming down the chimney, causing deterioration of the interior of the chimney and stopping draughts.
Types of Cowls, Caps and Bird Guards
Most Cowls are designed to keep out the rain with some kind of hood. In addition, there may be a mesh to keep out birds. There are different cowls for different fuel types; smokeless fuels require a stainless steel cowl, while coal and wood require a Cowl with a wider mesh to prevent blockages. There are also Cowls designed specifically to prevent or reduce down drafts