4 layers of paperless drywall, one layer durock, 1/2 inch granite tiles

[hankjrfan]

Gets me to over 2R for the hearth pad for the englander13 about to go in. Any problem with this design before i build it?
BTW, thanks to the many who have helped without even knowing it. learned a lot here lurking about. great site.
J.R.

 

[hankjrfan]

hardibacker shouldn't be used for hearth pads because of some cellulose in it. the durock is acceptable from what i've read because it has cement and fiberglass only.

it is a lot of layers, but that's what it takes to get it up to 2r.

micore might reduce some of my layers, but there's only two places in the state of MO listed as distributers of it,
and it's expensive.
the paperless drywall barely costs anything. hoping it's worthy of using. densguard i believe makes it.

 

[Tarmsolo60]

hardibacker shouldn't be used for hearth pads because of some cellulose in it. the durock is acceptable from what i've read because it has cement and fiberglass only.

it is a lot of layers, but that's what it takes to get it up to 2r.

micore might reduce some of my layers, but there's only two places in the state of MO listed as distributers of it,
and it's expensive.
the paperless drywall barely costs anything. hoping it's worthy of using. densguard i believe makes it.

Try calling a few local lumberyards about Micore. One near me had it in two days and it was $26 A 4X8 sheet. it's like r1.1 per 1/2" if i remember right.

 

[hankjrfan]

one of the micor distributors is about 90 miles away, 180 round trip.. the phone number was right there on the micor site, so i went ahead and called. he'd be willing to sell me a handful of sheets no problem.

and that's exactly what i will do if this is a bad idea.

but there's a lowes on the edge of town and i could obtain the paperless drywall quickly, stack it up as high as necessary for less money and get end up with adequate R value (2)

still wondering if the paperless drywall is adequate provided it is stacked high enough to get proper R value.

 

[hankjrfan]

well. fwiw, guess posterity if nothing else. i'm going to post this i found deep inside a densarmor paperless drywall informational sheet.

LimitationsDensArmor Plus Fireguard is a non-structural product and should not beused as a nailing base to support heavywall-mounted objects.It is intended for interior applicationsonly; it must be kept dry and not used where exposure to extreme moisture is continuous.
Do not use DensArmor Plus Fireguardwhere there is prolonged exposure to temperatures exceeding 125ºF, e.g.,adjacent to wood burning stoves,heating appliances, saunas or steamrooms.

soo. looks like i'll have to drive to get the micor. thanks for the replys.

 

[begreen]

Thanks for posting the safety info hankjrfan. You could build up durock layers, but would need about 7 thicknesses, which is kinda gross.

 

[Danno77]

Did ya ever get this thing done? I'm still working on designing an R-2 pad as well, and am getting frustrated with composition requirements.

 

[Danno77]

well. fwiw, guess posterity if nothing else. i'm going to post this i found deep inside a densarmor paperless drywall informational sheet.

LimitationsDensArmor Plus Fireguard is a non-structural product and should not beused as a nailing base to support heavywall-mounted objects.It is intended for interior applicationsonly; it must be kept dry and not used where exposure to extreme moisture is continuous.
Do not use DensArmor Plus Fireguardwhere there is prolonged exposure to temperatures exceeding 125ºF, e.g.,adjacent to wood burning stoves,heating appliances, saunas or steamrooms.

soo. looks like i'll have to drive to get the micor. thanks for the replys.

I see this post from late 2008, and have read through all the documentation I can find through GeorgiaPacific's website. Can you direct me to the document you read that in? I'm curious, because I found reference (in the documents I just checked) that suggests the documents were all updated in november of 08. I'm hoping they took that out, but really I just want to make sure I'm not missing something.

 

[asylum575]

I'm planning on using Micore also. I found a distributor 30 miles away and he will sell me 1- 4x8 1/2" sheet. I figure I'll rip it into 2- 4x4 sheets and have 1" of Micore, 1/2" of durock and some slate tile as a hearth. R value will be 2.85+ whatever the tile gives me. That's 1" of Micore and 1/2" of cement board. I checked with USG and Durock is .26 per 1/2". I wanted to make the hearth with enough R value so that if I replace the stove I'm set.

k r
Micore 300* 0.43 2.33
Wonderboard (cement board)* 1.92 0.52

 

[cre73]

If anyone close to central Illinois needs some micore let me know, I have 1.5 sheets of it I think. Not interested in shipping though. Come get it and have a good day. Located Taylorville, il

 

[Jags]

For anyone who cares: The new version of Durock is NOT rated for hearth use. The formula they now use includes foam beads. The beads can outgas during prolonged heat exposure.

The old stuff was good. The new stuff is not (for hearth use).

 

[asylum575]

Jags,

Interesting.

This is from US gypsum's website on Durock

***Non-combustible - panel is fire safe and is used in fire resistant designs***

(broken link removed to http://www.usg.com/navigate.do?resource=/USG_Marketing_Content/usg.com/web_files/products/prod_details/DUROCK_Brand_Cement_Board.htm)

 

[Jags]

Jags,

Interesting.

This is from US gypsum's website on Durock

***Non-combustible - panel is fire safe and is used in fire resistant designs***

(broken link removed to http://www.usg.com/navigate.do?resource=/USG_Marketing_Content/usg.com/web_files/products/prod_details/DUROCK_Brand_Cement_Board.htm)

Yes, Durock can be used in building fire resistant walls and partitions. That is true...but the product is NOT intended for long term, or constantly heated applications such as a hearth pad. USG specifically states that the Durock is NOT hearth approved. As well as, this has been confirmed with a call to their product engineers.

If you wish to hear it first hand, please call 1-800-USG4YOU.

 

[asylum575]

Jags,
Does this mean that it will become combustible over time? I was planning on using 1/2" durock for tile adhesion, with 1" of micore under it. Here is the USG website product description

DUROCK cement board provides a flat, durable base for premium finishes including glass and ceramic mosaics, ceramic and quarry tile, lugged tile, and thin stone and brick. Suitable for application to wood or steel framing spaced 16" o.c. in new construction and remodeling. It is ideal for use in partitions, walls, floors, soffits and ceilings in wet or dry areas. The mold- and moisture-resistant board does not deteriorate in the presence of water so it is extremely durable in areas such as baths, showers, kitchens and laundry rooms. Also suitable for exterior applications such as fences, mobile home skirting, agricultural buildings, garage wainscoting and exterior finishes; also adaptable for high-heat areas like fireplace fronts and UL-listed wall shield/floor protectors. DUROCK cement board is backed by a 30-year warranty for interior applications and a 10-year warranty for exterior applications. Use with DUROCK™ joint tape and DUROCK™ screws

I'm not doubting your research, but this is confusing. What should I use over the Micore boards for tiling? The 1" of Micore should be enough R value, I just need something that will take tile.

 

[Jags]

The old style (about 1+ year ago) was VERY suited for hearth application. The "new" version has styrofoam beads that can outgas when heated.

Call the number, they are very helpful and friendly people (by the way, I work in the industry).

Edit: it is possible that they "re-certified" it, but I am not aware of that. When the new version came out, that was one of the stinks about it, but the people using the stuff loved the reduced weight.

 

[Danno77]

...When the new version came out, that was one of the stinks about it...

Haha, funny choice of words.

 

[hankjrfan]

well. fwiw, guess posterity if nothing else. i'm going to post this i found deep inside a densarmor paperless drywall informational sheet.

LimitationsDensArmor Plus Fireguard is a non-structural product and should not beused as a nailing base to support heavywall-mounted objects.It is intended for interior applicationsonly; it must be kept dry and not used where exposure to extreme moisture is continuous.
Do not use DensArmor Plus Fireguardwhere there is prolonged exposure to temperatures exceeding 125ºF, e.g.,adjacent to wood burning stoves,heating appliances, saunas or steamrooms.

soo. looks like i'll have to drive to get the micor. thanks for the replys.

I see this post from late 2008, and have read through all the documentation I can find through GeorgiaPacific's website. Can you direct me to the document you read that in? I'm curious, because I found reference (in the documents I just checked) that suggests the documents were all updated in november of 08. I'm hoping they took that out, but really I just want to make sure I'm not missing something.

I'd have to dig for it again, but I started on the densguard website, then over to the products. It was a buried in a large pdf file.

Also, during the making of this thread, the micore didn't work out. Pressed for time, I went to lowes again and looked closely at the densguard. I'll probably get "flamed" for doing this, but i went ahead and built the hearth using the forumula contained in the title. I mean I had some fires over the winter too.... burned every day. no problems whatsoever. Not recommending others do it, but just relaying my own experience.

 

[Danno77]

thanks for the reply on that. I need to get working on building my hearth, so any more info is appreciated. I might just do what you did, but I'd rather be a "fool that knows better" than "just a fool." lol.