Construction of raised hearth extension

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Alagar

New Member
Nov 4, 2022
2
Colorado
Hi, I am getting ready to install a Superior WCT6940 / Astria Montecito Estate and am wondering how to properly construct a raised hearth extension such as is seen in this image from the manufacturer's webpage:
Fireplace image.jpg

Below is a copy of the manufacturer's instructions for hearth construction, but it depicts the hearth extension extending out flat from under the fireplace whereas I would like to raise it up as shown by the red box and then add a hearth stone of some type across the top as shown by the blue box.
Hearth extension construction instructions.jpg

The instructions require at least 1/2" non-combustible material below the fireplace and at least 1" cement board below the tile they depict on the flat hearth extension. What do I need to do to raise the hearth extension height by about 6" so that the hearth ledge is just below the fireplace front façade?

Any help or suggestions are greatly appreciated.

Thanks!
 
Hi, I am getting ready to install a Superior WCT6940 / Astria Montecito Estate and am wondering how to properly construct a raised hearth extension such as is seen in this image from the manufacturer's webpage:
View attachment 302070
Below is a copy of the manufacturer's instructions for hearth construction, but it depicts the hearth extension extending out flat from under the fireplace whereas I would like to raise it up as shown by the red box and then add a hearth stone of some type across the top as shown by the blue box.
View attachment 302071
The instructions require at least 1/2" non-combustible material below the fireplace and at least 1" cement board below the tile they depict on the flat hearth extension. What do I need to do to raise the hearth extension height by about 6" so that the hearth ledge is just below the fireplace front façade?

Any help or suggestions are greatly appreciated.

Thanks!
It looks to me like if you raise the hearth you will be covering the bottom vents
 
It's a good question. The manual doesn't directly address this. Instead, it talks about the hearth extension at the floor level. The picture looks like a studio shot with the fire or the whole stove photoshopped in. I would call Astria on this one. My gut tells me that I would want more insulation than 1" of cement board, but how much?
 
The vents are towards the bottom of the façade and then there's an additional 6" below the bottom of the façade to the bottom of the fireplace that is just plain sheet metal.

I'll try contacting IHP and see what they say.
 
Yes, I see what you want to do and reviewed older Lennox and BIS docs for this insert, but no additional info was found. If they are no help I would at least put a 1/2" layer of micore in between the cement board sheets for peace of mind.