clarification about hearth needed

[Gibraltar IV]

Ok guys, this is my first post, so be gentle...
I've read a lot of posts and still have this question, so hope you can help.
I'm installing an unlisted Gibraltar IV wood stove. It's all steel with a firebrick lining and 6" legs.
I want to follow the NFPA 211 guidance for unlisted stove floor protection, which says, among other things,:
"The top surface of the masonry is covered with sheet metal not less than 24 gauge [0.024 in. (0.61 mm)].

So if I go with the 2" of "closely spaced solid masonry," do I really have to put the sheet metal on the very top of it? I want slate on top, not sheet metal.

Specifically, I want to build a raised hearth with wood frame, put 2" of cement board layers on it, plus the sheet metal sandwiched in the cement board, then tile. It would seem logical that I could put the sheet metal in between layers of cement board, then tile, etc...., but that's not "the top surface" as 211 says.

I see very little sheet metal on top of any of the hearths in the forums, so what am I missing here?

Your advice will be appreciated..
Thanks.

 

[Nick Mystic]

Welcome to the forum Gibralter IV. I'm not familiar with the regulation you quoted, but I can tell you that you are correct in saying that not many hearths are covered in sheet metal! So, I'm thinking you must be misunderstanding the regulation you quoted. It's my understanding that when sheet metal is used in a hearth's construction it is to prevent hot embers from sliding down between non-combustibles, like loose bricks, and reaching a combustible, like a wooden floor. I've used sheet metal twice with stove setups I had at the time where I used unmortared bricks for my hearth pad. I'm sure someone familiar with the regulation you mentioned will soon give you an "official" interpretation of it. Good luck with your build.

 

[Gibraltar IV]

Welcome to the forum Gibralter IV. I'm not familiar with the regulation you quoted, but I can tell you that you are correct in saying that not many hearths are covered in sheet metal! So, I'm thinking you must be misunderstanding the regulation you quoted. It's my understanding that when sheet metal is used in a hearth's construction it is to prevent hot embers from sliding down between non-combustibles, like loose bricks, and reaching a combustible, like a wooden floor. I've used sheet metal twice with stove setups I had at the time where I used unmortared bricks for my hearth pad. I'm sure someone familiar with the regulation you mentioned will soon give you an "official" interpretation of it. Good luck with your build.

Thanks for input, Nick. What you said makes sense to me. I will incorporate sheet metal, just not on top.