hardibacker???? or durarock

[jotulburner]

Wich product is easier to use in construction of hearth pad???

 

[firefighterjake]

I think either is easy to use . . . but it seems as though the better product to use right now barring any changes would be the original (not NextGen) 1/2 inch Durock . . . followed by the Wonderboard. Hardiboard may be OK . . . Durock NextGen is questionable right now.

 

[begreen]

My understanding is that Hardibacker has cellulose in it and is not approved for hearth use. Use cement board and anchor according to instructions with their special screws and you will have a nice hearth.

 

[redkev]

I contacted USG and asked them about Nextgen. In their response they told me it is non-combustible, and this is a quote from USG website:

"The board is non-combustible and can be used in a variety of fire-rated designs. Its low thermal and hygrometric expansion help prevent finish cracking."

The USG website also contains this statement in their FAQ section:

Q: Can you achieve a one-hour fire-rating with only DUROCK® Cement Board Next Gen applied to each side of a partition?

A: No.

 

[begreen]

They really have messed up the messaging with NextGen. It would be great if they got this tested for hearth use and documented it.

This is an old thread on the subject that Goose pulled together:

https://www.hearth.com/econtent/index.php/forums/viewthread/9045/

 

[Hoopdancer]

Thanks for the link BeGreen. Very helpful and led to other helpful links in hearth building.

 

[firefighterjake]

I contacted USG and asked them about Nextgen. In their response they told me it is non-combustible, and this is a quote from USG website:

"The board is non-combustible and can be used in a variety of fire-rated designs. Its low thermal and hygrometric expansion help prevent finish cracking."

The USG website also contains this statement in their FAQ section:

Q: Can you achieve a one-hour fire-rating with only DUROCK® Cement Board Next Gen applied to each side of a partition?

A: No.

We've had more than a few threads on this very same topic . . . in my own opinion a member (I think it was Jags) actually talked to an engineer who designed the NextGen product and according to that conversation the NextGen Durock is not designed for use as a hearth. In my own talk with USG the tech I spoke with said he thought it should be OK for use as a hearth, but it wasn't rated and at this time USG is not saying to go ahead and use it as a hearth since it has not been tested or listed for such a use . . . it can however be used to achieve fire rating if you wanted to fire rate the area around your stove and hearth or enclose your boiler.

 

[Jags]

We've had more than a few threads on this very same topic . . . in my own opinion a member (I think it was Jags) actually talked to an engineer who designed the NextGen product and according to that conversation the NextGen Durock is not designed for use as a hearth. In my own talk with USG the tech I spoke with said he thought it should be OK for use as a hearth, but it wasn't rated and at this time USG is not saying to go ahead and use it as a hearth since it has not been tested or listed for such a use . . . it can however be used to achieve fire rating if you wanted to fire rate the area around your stove and hearth or enclose your boiler.

Eggzactly.

 

[minkaz]

Durock - reply from USG:
Because of the reformulation of the Durock Next Gen we are no longer recommending its use as a heat shield or floor protector around wood stoves or fire places.

Regards,

Chris Curtiss


Chris Curtiss
Schiller Park CSC
Specialist/Service Improvements/
Technical Support
Phone- 847-233-3327
[email protected]


That said, Home Depot still carries wonderboard for about 10 bucks per 3x5 foot sheet 1/2 inch thick.