gap between firebox / lintel

[brianmiller]

Should the gap between the lintel , which supports a stone surround , and the firebox be sealed?

[Jim Brewer]

[QUOTE=brianmiller;222526]Should the gap between the lintel , which supports a stone surround , and the firebox be sealed?[/QUOTE
Yes, definitely. Without a good seal there smoke, heat or flame could get into the concealed area and cause bad things to happen.