The front and back of the tray is turned down - eventually lead aprons will be inserted underneath.

The brick chimney is built, using sulfacrete cement to avoid formation of white deposits on the face of the bricks, caused by naturally ocurring sulphates in the bricks. Towards the top of the stack, two courses of brick have been brought out to provide a drip course, the wooden formwork providing a guide.

Two weep hole vents have been inserted in the bottom course of bricks on each side. .

A wooden formwork is made so that the lead aprons can be constructed to the correct size and angles.

The apron is welded to ensure a no leak seamless barrier to water.