Pacific Insert Hearth Dimension Question

[tkuhe]

So I am looking at the manual for the Pacific insert and the picture shows that you need 16" and 2" thick from the front of the fireplace, not the door, of non combustible hearth. It then shows a picture stating 16" from the glass for a non combustible floor covering, but does not elaborate? Is that correct? What defines a noncombustible floor covering?

 

[begreen]

The hearth extension beyond the actual 16" fireplace hearth can be any seamless non-combustible material that is fixed in place. This could be as simple as a screwed down sheet of metal, though most go for something more finished and attractive. This extension is what gives you the 16" protection from the door glass. Note, there is no harm at all in exceeding the minimum requirements.

Personally, I like to have a bit deeper extension. Some wood can really pop out hot embers, often when you least expect it. What is your current setup?

 

[tkuhe]

The hearth extension beyond the actual 16" fireplace hearth can be any seamless non-combustible material that is fixed in place. This could be as simple as a screwed down sheet of metal, though most go for something more finished and attractive. This extension is what gives you the 16" protection from the door glass. Note, there is no harm at all in exceeding the minimum requirements. I personally like to have a bit deeper extension. Some wood can really pop out hot embers, often when you least expect it.

So I just reread the top paragraph which states that if your floor is flush then you should extend the hearth out 23.5". Mine is pretty much flush and extends out 16" so I will need to add a minimum of two more rows of brick. Only trouble will be that if I do this using traditional bricks I will have to do some significant re-framing in the basement.
Is there any reason why I couldn't use some durock and half bricks for this?