Combustible Clearance Confusion

just had a Kozy Heat Z42 installed. We had to completely rip out our old prefab and mantel. I am getting ready to build a new mantel surround but am a little confused on combustible clearances. The manual gives a chart based on how far the combustible shelf will protrude from the wall and how high from the top of the fireplace it must be. We are looking at using a 9" shelf so that would put me in the 14" range from the top of the fireplace. Here's where I'm confused....since we are going to building a mantel surround, there will be a "header" that is just below the mantel shelf. This material will be made of 1" material (3/4" actual thickness) and will be in the neighborhood of 8" wide. According to the manual, combustible clearance on 3/4" protrusion is only 1". My question is this.....do I need to still measure 14" from the top of the fireplace to the bottom of the "header" or just make sure that my mantel shelf is 14" from the top of the fireplace? If I go 14" from the top of the fireplace to the bottom on the header, it's going to call for a much taller mantel surround.
Thanks!
on a side note......we are really enjoying the unit so far. I certainly haven't mastered the unit just yet and am tinkering with trying to get longer burn times and trying to push the air to different parts of the house. The oak that I'm using is extremely dry and burns really hot. We have the house fan on (without the heat actually on) try to pushing the air around.

oconnor said:

Its a bit hard to envision - is there a diagram in the manual you can post? I believe you are fine with the header at 1", and the mantel would be 14" from the fireplace.

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this is from page 18 of their manual

oconnor said:

OK. You are good at just under 14" from the fireplace for the 9 inch mantel based on that diagram. Basically imagine a no-mantel zone behind a line starting at the top of the fireplace face and extending to 11 1/4" out at 17" up.

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we certainly plan on having the "header" higher than 1" from the top of the fireplace, just not sure if I needed to go 14" or not. We are going to be using stacked stone in between the sides/top of the fireplace to the surround. If I had to guess, I'd say we would probably be in the neighborhood of 10" from the top of the fireplace to the bottom of the header. Just want to make sure this would be safe.

begreen said:

The "header" sounds like a face plate. Based on the chart I think you will be ok with the plan for the mantel at 14", the face plate is ok at 3/4" thick. But remember that the mantel height can always exceed the minimum requirement.

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sorry, still getting my fireplace lingo down- if we put the bottom of the header/face plate 10" from the top of the fireplace, that would put the bottom of our shelf in the neighborhood of 19" from the top of the fireplace. I just wasn't sure if I needed to have the header/face plate that high off (14"). We are planning on hanging our TV above the mantel shelf and wanted to keep it off the crown molding if possible