Good morning, I am looking to paint the walls of a fireplace, which contains a wood burning stove. The walls are covered with mortar and they are 55mm away from the side of the stove. 1. My understanding of the advice on your website is that I can apply two coats of Thermoguard wallcoat smoke and flame retardant topcoat. Is this correct? 2. I see that this paint protects the surface by expanding to produce an insulating layer in the presence of flame. Would I be correct in assuming that heat without flame does not cause this reaction? Many thanks, Andrew