# Painted Durock (or hardibacker) for Heat Shield



## pen (Nov 21, 2012)

Came across a dangerous situation a buddy has that needs a heat shield on a dime.

Wondering if anyone is using straight durock (or hardibacker) with the 1 inch spacers for air space behind it, that is simply painted for a side heat shield.

If so, how's it holding up?

Was standard or high heat paint used?

Also, how brittle is durock? I've only ever worked with hardibacker before. Wondering if it would be better to use hardibacker instead of durock for a standalone situation like this. Where it's located it should not be abused once up, just never worked with the stuff to know how brittle it is compared to the hardi

Thanks for the help

pen


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## firefighterjake (Nov 21, 2012)

The Durock I used (not the Next Generation) seemed pretty rugged . . . I mean I wouldn't put it between two floor joists without some type of sub-floor, but for a heat shield that is out of the way where it shouldn't get bashed I would imagine it would work well enough. Some of the left over pieces of Durock I have had kicking around in the garage look fine . . . after being buried under assorted pieces of sheetrock, scrap wood, etc.


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## pen (Nov 21, 2012)

firefighterjake said:


> The Durock I used (not the Next Generation) seemed pretty rugged . . . I mean I wouldn't put it between two floor joists without some type of sub-floor, but for a heat shield that is out of the way where it shouldn't get bashed I would imagine it would work well enough. Some of the left over pieces of Durock I have had kicking around in the garage look fine . . . after being buried under assorted pieces of sheetrock, scrap wood, etc.


 
That's great, thanks Jake. It'll save me about 10 bux in gas and an hour and a 1/2 to get the Durock versus hardibacker.

Now, wonder how putting paint on it would go. hmm.


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## David Tackett (Nov 21, 2012)

Durock is cement board and much better than hardibacker, IMO, for this application.


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## firefighterjake (Nov 21, 2012)

pen said:


> That's great, thanks Jake. It'll save me about 10 bux in gas and an hour and a 1/2 to get the Durock versus hardibacker.
> 
> Now, wonder how putting paint on it would go. hmm.


 
Maybe try a paint made to go on to cement . . . other than that . . . many of us have our stoves pretty close to the walls and don't have anything up on the walls other than painted sheetrock . . . no problems with the paint (although I have had issues with cracks in the sheetrock  -- but that's a whole other thread.)


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## Tramontana (Nov 21, 2012)

I would recommend wearing a mask or respirator if you use power tools for cutting.  Also, pre drilling pilot holes will help reduce spalling the face of the Durock.  

Another option for finishing would be to go with a gypsum veneer plaster that has an integral color.

Good luck.


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## milleo (Nov 21, 2012)

Durock next generation worked great for me but I did tile over it. Use a carbide blade when cutting it, I got 3' x 5' sheets and it is lighter than the old style durock.


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## BrowningBAR (Nov 21, 2012)

pen said:


> That's great, thanks Jake. It'll save me about 10 bux in gas and an hour and a 1/2 to get the Durock versus hardibacker.
> 
> Now, wonder how putting paint on it would go. hmm.


I put some up on the one side of the chimney that faces the stove (in the living room that has the Defiant in it). The chimney was old and left exposed for 100+ years as it was attached to a built in cabinet that we removed. We attached Durock to the chimney to provide a smooth surface to allow us to match the other two sides of the exposed chimney inside the home.

It worked well, but we are finding that the paint does not hold as well and tends to crack. We redid it this summer and it is holding up better, but we have two noticeable cracks in the paint. One crack is up top near the ceiling, the other is where the pipe enters the chimney.

So, we will probably touch it up again this summer.


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## Dakotas Dad (Nov 21, 2012)

I just added some concrete color to some mortar, and more or less stuccoed.. been three years now.. still looks good. Your color choices are limited though..


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## turbocruiser (Nov 21, 2012)

I'll echo all the above comments and add that perhaps the "paint" to use in this instance is that "UGL DryLock" paint that is specifically spec'd for concrete? It is designed to penetrate into and bond with the cement to prevent leaks, cracks, chips, etc. I imagine that would be the best type for longevity but I have not idea how it handles the heat. Ohh, don't use HardiBacker it is cellulose based and not actually cement based and I think that most of it has a grid design going through it too so that might not match the rest of room. In any case avoid HardiBacker for this application . Hope that helps.


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## pen (Nov 21, 2012)

Thanks for all the advice guys.

This heat shield is going behind a double barrel wood stove in a buddies cabin. Since nobody has ever sat around a double barrel stove and ogled at it's beauty, I think the natural look of durock will be just fine. Certainly a lot better than burning the joint down.  How it has never burnt before is beyond me.  I thought maybe if others had good luck in the past, that I'd paint it with some leftover stuff while I was there.

Thanks again,


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## begreen (Nov 21, 2012)

pen said:


> Came across a dangerous situation a buddy has that needs a heat shield on a dime.
> 
> Wondering if anyone is using straight durock (or hardibacker) with the 1 inch spacers for air space behind it, that is simply painted for a side heat shield.
> 
> ...


 

I did this for the Jotul 602 when it was installed in the kitchen. Painted Durock with high temp white. It wasn't the most attractive shield, but stood up well. We had no issues for the 12 yrs it did the job.


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## pen (Nov 21, 2012)

begreen said:


> I did this for the Jotul 602 when it was installed in the kitchen. Painted Durock with high temp white. It wasn't the most attractive shield, but stood up well.


 
Good to know,


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## begreen (Nov 21, 2012)

IIRC it was engine paint. Nothing special. It never peeled or anything.


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## bag of hammers (Nov 21, 2012)

Used 1/2 Durock in my original camp install with metal furring strips (leftover bits) for spacing. This was before the "next generation" product so I can't speak to the newer stuff. No paint (didn't care about aesthetics). It's been up for over 10 years now although I haven't run that stove in a couple years. I used leftover pieces of metal furring strip close to the edges and I had no problem. As mentioned, dust mask when cutting, and only cut outside (sorry that's probably obvious, but it makes a ton of silica dust and huge mess). But I did find it easy to make a nice smooth cut with an old skilsaw circular saw and standard masonry blades.


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## BillT (Nov 21, 2012)

I would cut the old Durock by scoring and snapping with a special scoring tool.

I haven't tried the new stuff yet, but can that be still scored and snapped?


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## turbocruiser (Nov 21, 2012)

BillT said:


> I would cut the old Durock by scoring and snapping with a special scoring tool.
> 
> I haven't tried the new stuff yet, but can that be still scored and snapped?



It can be but it is best to cut with circular  saw with special  blade and while also wearing dust mask.  This produces the smoothest cut.


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## Tramontana (Nov 21, 2012)

Yes, they now are marketing specialty saw blades for cementitious products such as Hardipanels and Durock.

Wish they had been available when I needed them instead of destroying decent carbide toothed blades.

Cheers!


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## northernontario (Nov 22, 2012)

If this is just going in a cabin, why not use a metal sheet?  I used a 4x8 sheet from a HVAC/duct work shop... The metal reflects heat instead of absorbing it... gives you a higher reduction in clearances (more effective). 

Of course the smaller 3x5 sheets are easier to work with.  I also used some 1/4" hardibacker boards in my install.  It's all in the basement... pretty was not a requirement.  Every person who came to inspect (building inspector, WETT inspector, insurance inspector) said it was one of the best installs ever.  I have a layer of cement board over the old drywall and exposed studs, and then the air gap and clearance reduction barrier (metal or more cement board).  In one spot I did a double air gap... although code only allows a max of 67% reduction (metal sheet), it's wood studs + air gap + cement board + air gap + metal sheet.  Those studs stay nice and cool... but they're about 7" from some single-wall black pipe.


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## pen (Nov 22, 2012)

Got things all put back together last night, and used the durock. Much safer than this setup has ever been in the past.

Used a 1 1/4 inch air space.  It's amazing to look at this installation before, and know how close that barrel stove burned to the pine board wall when it would be glowing.  Very lucky nothing every happened. 

Everyone's happy now. Thanks for the advice guys.

pen


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## begreen (Nov 22, 2012)

That's got to be much safer. Did you end up painting it or is it just raw Durock?


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## pen (Nov 22, 2012)

begreen said:


> That's got to be much safer. Did you end up painting it or is it just raw Durock?


 
It's raw, and to be quite honest, doesn't look that terrible considering it's in a rustic cabin.  The stove is in an out of the way area, and certainly not the center of attention.  I mentioned having some paint that I could use on it (high heat like you mentioned) and that comment evoked a bunch of belly laughter.

It was a bit step for them to accept the need for the heat shield in the first place.


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## BillT (Nov 22, 2012)

Just for what it is worth, when I was checking on the Micore I was looking for, I asked the guy at the USG Headquarters about the "new" Durock. He told me that it has a better R-Value and has increased to .39, but at the same time he said the Fire Resistance was reduced down to 125 degrees.

Just for curiosity, I asked him if the old stuff was still available and he said that no, it wasn't.

Maybe we should update our info that we have on record. I would recommend to verify what I was told though to make it official.

Bill


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## raybonz (Nov 22, 2012)

BillT said:


> Just for what it is worth, when I was checking on the Micore I was looking for, I asked the guy at the USG Headquarters about the "new" Durock. He told me that it has a better R-Value and has increased to .39, but at the same time he said the Fire Resistance was reduced down to 125 degrees.
> 
> Just for curiosity, I asked him if the old stuff was still available and he said that no, it wasn't.
> 
> ...


 


BillT said:


> He told me that it has a better R-Value and has increased to .39, but at the same time he said the Fire Resistance was reduced down to 125 degrees.


 
That makes no sense to me at all... There is no way you're gonna ignite this cement board especially at 125 degrees!

Ray


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## pen (Nov 22, 2012)

BillT said:


> but at the same time he said the Fire Resistance was reduced down to 125 degrees.


 
That is not correct.  Next Gen durock is fine for heat shields.  Cement boards such as PermaBase are not ok. 

Here's the literature on it http://www.usg.com/durock-cement-board.html#tab-features

Here's the cliff notes version:

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

*DUROCK cement board Next Gen includes a wind load rating of 30 PSF and is UL Classified for fire performance.  It offers a 30-year transferable warranty for interior applications and a 10-year transferable warranty for exterior applications.*

pen


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## begreen (Nov 22, 2012)

pen said:


> It's raw, and to be quite honest, doesn't look that terrible considering it's in a rustic cabin. The stove is in an out of the way area, and certainly not the center of attention. I mentioned having some paint that I could use on it (high heat like you mentioned) and that comment evoked a bunch of belly laughter.
> 
> It was a bit step for them to accept the need for the heat shield in the first place.


 

LOL, Real men don't do heat shields?  I can hear the comments now. Are you going to trim the edges with a nice fringe?


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## pen (Nov 22, 2012)

begreen said:


> LOL, Real men don't do heat shields? I can hear the comments now. Are you going to trim the edges with a nice fringe?


 
Spot on. Tough crowd, but great guys. Fringe? haha, no!

I'm just happy it's much safer now.

The cabin is "paneled" with pine boards that were put up green right on the studs. Which means there is now a 1/2 inch air gap between each of them (including the ceiling). The room used to be cathedral style, but now has what can only be described as a pine board "drop ceiling", except with gaps between each board.

With so much circulation around the boards that make up the walls and ceiling, if anything ever took off in that room, I don't think it'd take 90 seconds to be fully engulfed.

For 25 years, there has been nothing but a single asbestos like (or actual) board that looks like brick measuring 30inches by 36 inches to protect the wall from the bottom barrel of the stove (obviously not even covering that completely). Then, 8 - 10 inches above that, another identical board for the top barrel. This stove was about 15 inches from this pine wall. Those asbestos boards were screwed directly to the pine, no air space. The durorock went with 1.25 inch air space against the wall to protect it from the bottom barrel, I re-purposed the old fake brick asbestos panels on their side to form a continuous heat shield right up the wall.

Finally this year they decided that the old stove had seen enough service, and had a new one built. I was asked to come out and help remove the old one and install this one. After putting in the new stove, light got behind the stove next to their small panels and it was evident that the pine around their small wall shields was scorched.

I spoke with the son of the owner and told him I was going to go out and put up a wall shield, with or without his consent. He told his father, the two went and for the first time saw the scorched wood, and then became quite agreeable to the wall shield.

It had been there for so long, with no problems, they simply thought it was safe and just honestly never gave it another thought.

Considering drunks (myself included in that elite category of individual) sleep within spitting distance of that stove several times per year, I'm really happy it's done.

Thanks again for the help guys, as always.

pen


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## BillT (Nov 22, 2012)

raybonz said:


> That makes no sense to me at all... There is no way you're gonna ignite this cement board especially at 125 degrees!
> 
> Ray


 
 It didn't sound right to me either, so I was questioning him about it.  The answer he gave me was "It's starts to break-down after 125".  In my opinion, I took that as them only calling that number, the number to what they would stand up to. 

Other than that, I'm just repeating what the guy told me.  As mentioned, it was the guy at the USG Headquarters in Chicago, Ill, phone number (312) 606-4000.  He was the guy that I got transfered to when I was asking about the Micore.  It might have been the Tech guy, but since I was just asking about Micore availablity, I didn't pay extra attention to that. 

There is always that chance that he could be wrong, but we should probably ask USG for those specific specs in writing.

Bill


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## pen (Nov 22, 2012)

You can find them online yourself with a search, or just follow the USG link I gave earlier.

A board called permabase, which has actual beads of styrofoam in it that are visible, cannot be used over 220 degrees.

The guy just flat out was wrong, either he misquoted something by accident, or what happened, who knows, but his info is incorrect.

pen


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## BillT (Nov 22, 2012)

pen said:


> That is not correct. Next Gen durock is fine for heat shields. Cement boards such as PermaBase are not ok.
> 
> Here's the literature on it http://www.usg.com/durock-cement-board.html#tab-features
> 
> ...


 
It's nice to see all the good things written about it, as I have always liked the product and have confidence in it. 

But, it doesn't state anything in a Fire Rating or Resistance in the form of Degrees.  As mentioned in my post above, we should try to get that info from them in writing.

Bill


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## pen (Nov 22, 2012)

Here's another USG link http://www.usg.com/rc/system-catalogs/durock-cement-board-system-guide-en-SA932.pdf

pen


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## pen (Nov 22, 2012)

BillT said:


> It's nice to see all the good things written about it, as I have always liked the product and have confidence in it.
> 
> But, it doesn't state anything in a Fire Rating or Resistance in the form of Degrees. As mentioned in my post above, we should try to get that info from them in writing.
> 
> Bill


 
I don't think you are going to find it because it's listed as 0 for combustibility.  It just doesn't burn.


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## BillT (Nov 22, 2012)

pen said:


> You can find them online yourself with a search, or just follow the USG link I gave earlier.
> 
> A board called permabase, which has actual beads of styrofoam in it that are visible, cannot be used over 220 degrees.
> 
> ...


 
Pen, you were responding to mine at the same time that I was responding to your earlier post, lol.

I agree that he could be wrong. When I was talking to him, just to make sure I verifed with him that we were talking about the new type of Durock. I now hope that he wasn't wrong about the .39 R-Value. But, in my opinion, it is all enough to pursue it and get the specs in writing from them.

I will actually call again myself, but it would probably be better to have someone with some authority from this board to request the ratings in writing, or get them to add it to their link provided. Even if he is wrong, it would nice to have whatever specs they actually are, listed.

Bill


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## bag of hammers (Nov 22, 2012)

pen said:


> It had been there for so long, with no problems, they simply thought it was safe and just honestly never gave it another thought.
> 
> Considering drunks (myself included in that elite category of individual) sleep within spitting distance of that stove several times per year, I'm really happy it's done.
> 
> ...


Wow you just brought back a lot of memories - fuzzy weekends spent in some pretty interesting old shacks on some of the backcountry  lakes up here in the middle of nowhere.  Amazing we're still alive. Lots of fun though.


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## pen (Nov 22, 2012)

BillT said:


> Pen, you were responding to mine at the same time that I was responding to your earlier post, lol.
> 
> I agree that he could be wrong. When I was talking to him, just to make sure I verifed with him that we were talking about the new type of Durock. I now hope that he wasn't wrong about the .39 R-Value. But, in my opinion, it is all enough to pursue it and get the specs in writing from them.
> 
> ...


 
This document supports the .39 r-value if you scroll down a few pages.

http://www.usg.com/rc/data-submittal-sheets/panels/durock/durock-cement-board-submittal-CB399.pdf

pen


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## pen (Nov 22, 2012)

They list durock passes the ASTM 136E combustibility test, which is why they don't give you the number.

From what I can find, this test is with a furnace set to 750 or 1382 http://gigacrete.com/wp-content/uploads/2012/10/GigaCrete-3116593SAT-004-PlasterMax-ASTM-E136-report1.pdf 

It looks as though I'd have to pay cash for the actual ASTM 136E explanations document. The link above is the closest thing I can find to specifics about the test w/out handing over cash.

ETA: Here's another link to support the 750 temp associated with this test. http://www.ngctestingservices.com/fire.html

pen


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## BillT (Nov 22, 2012)

pen said:


> This document supports the .39 r-value if you scroll down a few pages.
> 
> http://www.usg.com/rc/data-submittal-sheets/panels/durock/durock-cement-board-submittal-CB399.pdf
> 
> pen


 
Pen,

Appreciate the link, as I have not seen that one before.  I also noticed the .39 R-Value on it, which I was glad to see.

As mentioned, just to make things clear and rule out any doubts, I will be calling back.  Only this time, either way, I will be getting the name of the person that I talked to.  It is something that I usually get, but as mentioned, the main purpose of my call was for Micore. 

Bill


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## raybonz (Nov 23, 2012)

Bottom line is the Durock NexGen is better than the original Durock. I used 2 layers on my hearth and it worked great..Greatly improved R-value and easier to work with.. Knock on wood my hearth has held up fine so far..

Ray


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## DMbekus (Nov 23, 2012)

pen said:


> Came across a dangerous situation a buddy has that needs a heat shield on a dime.
> 
> Wondering if anyone is using straight durock (or hardibacker) with the 1 inch spacers for air space behind it, that is simply painted for a side heat shield.
> 
> ...


 
I used hardiboard, only about 3 weeks though,no paint yet. Easy to install, smooth for paint and cheap.
From thier specs; 
*"Non-Combustibility*

HardieBacker® cement board is recognized for use in non-combustible construction in NER-405.
*Basic Composition/Size*

90% Portland cement and ground sand. HardieBacker® board contains no asbestos, glass mesh, formaldehyde, or gypsum
*Thermal Resistance*

(Approximate value) 1/4'' thick: R:0.13"


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## bag of hammers (Nov 23, 2012)

pen said:


> A board called permabase, which has actual beads of styrofoam in it that are visible, cannot be used over 220 degrees.


 
I noticed that when I used the permabase product in a shower install (a great tile backer).  This is a good point,, and a great thread IMHO - I've noticed  people often seem to just refer to everything (permabase, durock, hardiboard, etc.) as "cement board", but they all have different properties, applications,etc.


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## begreen (Nov 23, 2012)

pen said:


> Spot on. Tough crowd, but great guys. Fringe? haha, no!
> 
> I spoke with the son of the owner and told him I was going to go out and put up a wall shield, with or without his consent. He told his father, the two went and for the first time saw the scorched wood, and then became quite agreeable to the wall shield.
> 
> It had been there for so long, with no problems, they simply thought it was safe and just honestly never gave it another thought.


 
Problems with this kind of installation often only occur once. There are lots of burnt up cabins in the woods. I'm real glad to hear that no one became a statistic here.


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## firefighterjake (Nov 24, 2012)

pen said:


> . . .
> It had been there for so long, with no problems, they simply thought it was safe and just honestly never gave it another thought.. . .
> 
> pen


 

Sadly we see this a lot . . . folks assume that since something has been in place for years without issue that it is safe . . . until that "one time."


Well done Pen!


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## BillT (Nov 27, 2012)

BillT said:


> Pen,
> 
> Appreciate the link, as I have not seen that one before. I also noticed the .39 R-Value on it, which I was glad to see.
> 
> ...


 
Well guys, I finally got a chance to call back. I talked to a nice guy in the Techincal Dept at USG in Chicago. It was a different guy this time than the other day, which I was glad to get. He echoed every single thing that the first guy stated. Sorry to say, but that included that the New Generation Durock Panels are only good to 125 Degrees, according to them.

I also asked him what the old Durock was good to and he did not have that handy. He said that he would have to research and I didn't ask him to do that at this time, but I am curious to what they say we lost from the old panel to the new panel.

Although I did ask him why they quit making the old panel if it was such a better product for heat protection. His answer was that they found the new panel to be better and being lighter he told me that "Light is in".

I also asked if they having any plans making the old panel again and the answer was no.

I also got his name this time and a direct dial number to the Tech Dept if anyone would like to call to re-verify what I have been told. Just contact me for that info.

Bill


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## raybonz (Nov 27, 2012)

BillT said:


> Well guys, I finally got a chance to call back. I talked to a nice guy in the Techincal Dept at USG in Chicago. It was a different guy this time than the other day, which I was glad to get. He echoed every single thing that the first guy stated. Sorry to say, but that included that the New Generation Durock Panels are only good to 125 Degrees, according to them.
> 
> I also asked him what the old Durock was good to and he did not have that handy. He said that he would have to research and I didn't ask him to do that at this time, but I am curious to what they say we lost from the old panel to the new panel.
> 
> ...


This still makes no sense to me at all.. Taken from Durock NexGen below..


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## ScotO (Nov 27, 2012)

BillT said:


> Sorry to say, but that included that the New Generation Durock Panels are only good to 125 Degrees, according to them.


 I, like Raybonz, find it hard to believe that the Durock NexGen panels are only good to 125 degrees........maybe he meant celcius? And you have the Permacore, which has a chitload of styrofoam balls in it and clearly states in the data sheet it is NOT a non-combustible board, and they claim it's good to 220 degrees? Something isn't kosher here........


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## pen (Nov 27, 2012)

Bill, thanks for calling.  Did you ask why his information is in conflict with all of the NextGen Durock info that's available online?


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## pen (Nov 27, 2012)

Scotty Overkill said:


> I, like Raybonz, find it hard to believe that the Durock NexGen panels are only good to 125 degrees........maybe he meant celcius? And you have the Permacore, which has a chitload of styrofoam balls in it and clearly states in the data sheet it is NOT a non-combustible board, and they claim it's good to 220 degrees? Something isn't kosher here........


 
My thoughts exactly. Very puzzling


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## bag of hammers (Nov 27, 2012)

BillT said:


> I also asked if they having any plans making the old panel again and the answer was no.


 
That's really disappointing.  The durock board is great for many projects.  I used durock (and some metal studs) to frame in the front of an old hunting shack stove - using it for an outside feed sauna.


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## BillT (Nov 27, 2012)

I agree, but I encourage you all to call too. Actually would like to see someone else call so you can talk to them directly and ask some of the questions that could be better qualified than I could ask. USG Corp phone number is 312-606-4000 and their direct dial number to the Technical Department is 800-874-4968.

Keep us posted.

Bill


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## BillT (Nov 27, 2012)

pen said:


> Did you ask why his information is in conflict with all of the NextGen Durock info that's available online?


 
I more or less shyed away from that as I believe that the online info does not quote an actual number in Degrees as they so on the phone.

Another reason why I would like to see someone else call that is more knowledgable than I am to "confront" them on it.

Bill


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## pen (Nov 27, 2012)

BillT said:


> I more or less shyed away from that as I believe that the online info does not quote an actual number in Degrees as they so on the phone.
> 
> Another reason why I would like to see someone else call that is more knowledgable than I am to "confront" them on it.
> 
> Bill


 

I'm surprised too Bill.  Confusion like this is supposed to be prevented by the name change (which durock did) when changing their product.  Hmmmm


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## BillT (Nov 27, 2012)

Another thing that I have realized in my research is that I believe the New Generation Panels are just more profitable to USG.  Something that I believe is true, but also something that they are not going to readily admit.

Bill


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## raybonz (Nov 27, 2012)

Scotty Overkill said:


> I, like Raybonz, find it hard to believe that the Durock NexGen panels are only good to 125 degrees........maybe he meant celcius? And you have the Permacore, which has a chitload of styrofoam balls in it and clearly states in the data sheet it is NOT a non-combustible board, and they claim it's good to 220 degrees? Something isn't kosher here........


You can't ignite this stuff with a blowtorch Scott!!

Ray


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## ScotO (Nov 27, 2012)

raybonz said:


> You can't ignite this stuff with a blowtorch Scott!!
> 
> Ray


I can tell you for a fact first hand that I just installed Durock NextGen on the face of my Napoleon NZ3000 chase, above the fireplace. I had a decent fire going in it last night, kinda some "dry runs" for the fireplace before we install the stone veneer on it later this week. I used a digital thermal meter on it and the temps right above the fireplace, without the blower on, reached over 247 degrees on the durock that was directly above the shroud outlets. The area for several feet above the stove must contain non combustional material per code. Metal studs, non-combustible cement board, etc. Those temps prompted no combustion, no ill-effects (other than a couple of hairline cracks, which for those that use durock in areas that get warm know that durock has moisture in it, and when it dries out it will crack a little). The metal lathe and scratchcoat will alleviate that. No smoke, no combustion, nothing. Something just doesn't jive with what that guy told the caller.........


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## raybonz (Nov 27, 2012)

Scotty Overkill said:


> I can tell you for a fact first hand that I just installed Durock NextGen on the face of my Napoleon NZ3000 chase, above the fireplace. I had a decent fire going in it last night, kinda some "dry runs" for the fireplace before we install the stone veneer on it later this week. I used a digital thermal meter on it and the temps right above the fireplace, without the blower on, reached over 247 degrees on the durock that was directly above the shroud outlets. The area for several feet above the stove must contain non combustional material per code. Metal studs, non-combustible cement board, etc. Those temps prompted no combustion, no ill-effects (other than a couple of hairline cracks, which for those that use durock in areas that get warm know that durock has moisture in it, and when it dries out it will crack a little). The metal lathe and scratchcoat will alleviate that. No smoke, no combustion, nothing. Something just doesn't jive with what that guy told the caller.........


Tiny stress cracks are normal according to Durock and nothing to worry about.. Yup you will not burn this stuff! I recall a forum member tried to burn it over a hot barrel fire for hours with direct flame on it and it didn't burn..

Ray


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## GrampaDennis (Nov 27, 2012)

raybonz said:


> You can't ignite this stuff with a blowtorch Scott!!
> 
> Ray


This is not an "official" test, but I tried to light the 1/2" HardiBacker with a MAPP gas torch. I could make it glow red, but it died right out when I pulled the torch away. The surface is some kind of fiberous stuff, but the interior of the board is more cementicious. Even though the cut edge had a little fuzz on it, I could not get the fuzz to burn when I took the torch away.


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## ScotO (Nov 27, 2012)

raybonz said:


> Tiny stress cracks are normal according to Durock and nothing to worry about.. Yup you will not burn this stuff! I recall a forum member tried to burn it over a hot barrel fire for hours with direct flame on it and it didn't burn..
> 
> Ray


there were members on here last year making temporary baffles for their stoves out of it last year!  Now, that is not recommended by any means at all, but just saying that it was done and it apparently worked.......


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## raybonz (Nov 27, 2012)

Scotty Overkill said:


> there were members on here last year making temporary baffles for their stoves out of it last year! Now, that is not recommended by any means at all, but just saying that it was done and it apparently worked.......


That will work as long as you don't exceed 124 degrees lol..

Ray


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## Dad the Handyman (Oct 28, 2013)

ScotO said:


> I can tell you for a fact first hand that I just installed Durock NextGen on the face of my Napoleon NZ3000 chase, above the fireplace. I had a decent fire going in it last night, kinda some "dry runs" for the fireplace before we install the stone veneer on it later this week. I used a digital thermal meter on it and the temps right above the fireplace, without the blower on, reached over 247 degrees on the durock that was directly above the shroud outlets. The area for several feet above the stove must contain non combustional material per code. Metal studs, non-combustible cement board, etc. Those temps prompted no combustion, no ill-effects (other than a couple of hairline cracks, which for those that use durock in areas that get warm know that durock has moisture in it, and when it dries out it will crack a little). The metal lathe and scratchcoat will alleviate that. No smoke, no combustion, nothing. Something just doesn't jive with what that guy told the caller.........



ScotO, you said that "the area for several feet above the stove must contain non-combustible material.  Metal studs..."    My Tradition CE manual states 3.4.3 Framing, Facing and Mantel
A.  Frame the fireplace u sing 2 x3 or heavier lumber
B. Warning: "Combustible materials cannot be used in the space directly above the fireplace, *except * for the studs above the facade that support the facing and mantel.   This area must remain empty for a height of 6'8" from the base of the fireplace.   

Did yours say that, or did it specifically say that the studs used for the front of the chase had to be metal?

The reason I am asking, is that I want to do something similar to yours, on a smaller scale, and want a wood mantel.   I don't think I could possibly attach a wooden mantel to those flimsy metal studs, so I planned to use a wooden "header" above the triangles on top of the stove so I can drill into them.   If I didn't use wood do you have a guess how I could install a mantel there?


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