Good Morning,
Nice space. Its hard to tell from the photos just how big the space needing to be filled is however
Dap 18854 High Heat Mortar Raw Building Material, Black
should work well. It can ... read more
Condensation from the differential temperature is of course on answer. The other and more concerning is the furnace or force air unit (FAU). I would recommend contacting a licenced heating contracto ... read more