How thick should Heat Stop castable products (Insul Stick, Insul Cast, and Heat Cast 40) be applied?

How thick should Heat Stop castable products (Insul Stick, Insul Cast, and Heat Cast 40) be applied?

Insul Stick is usually applied as a parged product ¼” to ½” thick. It may be cast thicker. Insul Cast is typically cast 2” thick under the hearth, behind the firebox or over the oven dome. It may be cast thicker. Heat Cast 40 is typically cast 2” thick for replacement of firebrick in a firebox smoke chamber or oven. It may also be cast thicker.