ceiling / wall protection ( cement wall board )

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jeff123

New Member
Hearth Supporter
Jun 28, 2008
60
eastern,ct
If you use a product from Homedepot (PermaBase® BRAND Cement Board) on the ceiling in my celler does that reduce the safe distance for the black pipe from 18" to something less ? My assumption is the cement board is non combustable and should be a safe solution.
 
Have you got some sort of horizontal run beneath the ceiling that you're concerned about, or what? Going up through the ceiling you need to transition to Class A chimney, anyway. Durock or any product like it provides little in terms of insulation value, just like masonry (brick). In a vertical situation, the insulation really comes from a ventilated air space between the durock, masonry, whatever and the combustible wall material. Tell us more about the configuration of the installation you're contemplating. Rick
 
If it were Durock or other pure cement board, it might reduce the clearance if there is a one inch ventilated air gap between the cement board and the combustible (ceiling joists). Otherwise, I don't think so.

However, if this is the product that has little styrofoam balls in the cement to lighten it, then I doubt it. It has a pretty low temp rating. From the mfg data sheet:

"PermaBase Cement Board should not be exposed to temperatures over 220°F."
 
I'm doing a fairly straight forward install. The stove is going in an unfinsihed basement into a masonary flue. I was considering using the cement board on the ceiling ( unfinished floor joice). AS of now I have 18" clearance between the black pipe and the ceiling but I thought I would install the cement board for an extra good feeling about safety
 
It certainly won't hurt, but I would use the a true cement board product instead of the permabase.
 
I have a lot to learn, I thought the permabse was reall cement board.

Would you know if HD or Lowes carrys the real stuff and if so what's it called ?

thanks so much for all the help.
 
It is real cement board, but not pure cement board. There are product out there that use combustible material as filler in the board. These are not certified for heat shielding.

HD and Lowes usually carry Durock brand cement board and maybe Wonderboard.
 
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