After the fact hearthpad question

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Maineah

New Member
Hearth Supporter
Jun 22, 2008
23
Seal Harbor, Maine
Installed Napoleon 1400 last weekend. The manual called for an approved non combustable hearth pad but I built my own using 2x4 3/4 ply, 2 layers of 1/2 durarock and slate tile. Should have I bought an prefab hearth pad or am I ok?
 
what does the manual for the stove call for in terms of R-value protection for the hearthpad?

you should be fine... mine called for .74 r value and i used 3 layers of durock and 1.75-2 inches of natural stone... i'm over the min spec but....

to be honest, the hearth is my coolest part of the entire setup, temps hit 130 max!
 
You should be totally fine... non-combustible is exactly what you built!
 
You're good to go. The hearth meets the stove requirements. Fire that baby up and get warm!
 
Maineah said:
Installed Napoleon 1400 last weekend. The manual called for an approved non combustable hearth pad but I built my own using 2x4 3/4 ply, 2 layers of 1/2 durarock and slate tile. Should have I bought an prefab hearth pad or am I ok?

Assuming there is no R value requirements . . . you should be fine . . . providing that you bought the half inch Durock which specifically is listed for floor protection as a hearth . . . the Durock that you bought should have had a sticker stating that it was tested by UL and approved for floor protection. Here in Bangor our Inspector (who lives down in Sorrento incidentally) is more than happy to see Durock being used for hearths . . . and in fact using the almighty power of AHJ he even requires pellet stoves (which often don't have very strict hearth requirements) to have a pre-fab or listed floor protection for the hearth.
 
Jake, I've read on USG's website that they are phasing out the original Durock in favor of the Next Generation product. To my knowledge, the Next Gen does not have UL approval. Is that correct or has this product been approved for hearth usage? My understanding is that it has styrofoam pellets in it. I'm concerned about how it will outgas in high heat situations or actual house fires. Do you have any data on that?
 
BeGreen said:
Jake, I've read on USG's website that they are phasing out the original Durock in favor of the Next Generation product. To my knowledge, the Next Gen does not have UL approval. Is that correct or has this product been approved for hearth usage? My understanding is that it has styrofoam pellets in it. I'm concerned about how it will outgas in high heat situations or actual house fires. Do you have any data on that?

Nope, no info . . . just what I've read here. I would hope that the next generation product might still be able to meet the UL floor protection requirement . . . but then again maybe Durock doesn't sell enough of this product for hearths to make the expense of getting it tested and listed to make it worthwhile -- only time will tell I suppose.
 
Hey Jake,

On another issue, been running my wood stove a few times and I have it well within the minimum clearence on the rear and side as wellas the stove pipe. But the sheet rock wall behind the stove pipe gets hot when I have the stove cranking. I can hold my hand on it but it definately is warm. What do you think?
 
Maineah said:
Hey Jake,

On another issue, been running my wood stove a few times and I have it well within the minimum clearence on the rear and side as wellas the stove pipe. But the sheet rock wall behind the stove pipe gets hot when I have the stove cranking. I can hold my hand on it but it definately is warm. What do you think?

This issue has come up before in other threads . . . as long as the stove was installed with the proper clearances and floor protection you should be all set.

The line of thinking here is that the stove manufacturers go through a lot of time and money to figure out the proper clearances and the last thing they would want to do is tell folks to install the stoves at X-distance and then have the homeowner burn their house down due to the stove being too close. In fact, if anything the companies are probably hedging their bets and incorporating a margin of error figuring that some numbskull out there will put the stove even closer.

Other threads have stated that it is normal for the drywall (assuming you have a conventional drywall wall here) sucks up and retains the heat which is normal for a radiating heating device . . . and if you can actually put your hand on the surface for more than a few seconds without burning it should be well within the ignition temp of the drywall.

I have a corner install and being the anal-retentive type (I did mention that I added in the listed Durock for my hearth even though I didn't technically need to, right? :) ) I opted to install the rear shield, use double wall stove pipe and even then I opted to keep it out 13 inches from the wall vs. the 9 (at least I think the minimum for that stove configuration was 9) inches . . . I didn't miss the 4 inches and bought some peace of mind.

My wall does get warm to the touch, but no more so than the nearby grandfather clock or myself after having the woodstove cranking for several hours. :)
 
Thanks, yeah I have the double wall stove pipe at 15 inches from the wall and the back of the stove is 9 from wall but is rated for 6 inches. My side is 11 inch out for a 10 inch clearence and has a kitchen cabinet next to it. I was just a bit surprised that both the wall and cabinet got hot that's all.
 
If you can hold your hand on it, your good to go. It can actually feel quite hot to the touch and still be well withing the acceptable limits. Its when you CAN'T hold your hand on it for only a couple of seconds that you will want to look into things closer.
 
Hey BeGreen - I have inside contacts with USG and just made a phone call. The next Gen Durock IS UL approved for fire rated assemblys..but IS NOT RATED FOR HEARTH USAGE.

Thats the official word.

Edit: I think I will start a new thread just to get the word out.
 
Maineah said:
Thanks, yeah I have the double wall stove pipe at 15 inches from the wall and the back of the stove is 9 from wall but is rated for 6 inches. My side is 11 inch out for a 10 inch clearence and has a kitchen cabinet next to it. I was just a bit surprised that both the wall and cabinet got hot that's all.

From the sounds of it you're well within specs for the stove pipe . . . the Jotul manual that I just dug out says the double wall pipe can be located as little as 6 inches from any unprotected vertical or horizontal space and you're saying you've got 15 inches.

The rear of the stove is 9 inches away from the rear but you say your minimum is 6 inches which means you must also have the rear heatshield installed on your stove.

However, I'm a but confused . . . the side clearance for the Jotul Oslo is 14 inches (for all configurations) unless you have a protected surface that meets NFPA 211 requirements. I'm not sure where you're getting the 10 inch clearance.
 
Jags said:
Hey BeGreen - I have inside contacts with USG and just made a phone call. The next Gen Durock IS UL approved for fire rated assemblys..but IS NOT RATED FOR HEARTH USAGE.

Thats the official word.

Edit: I think I will start a new thread just to get the word out.

I'm glad I bought my Durock when I did . . . so the next logical question for future hearthbuilders however will be what product can they buy that can be used for hearths? Is there anything out there listed right now?
 
Maineah said:
Oh my stove is not a Jotul, it's a Napoleon 1400.

Well shove a hot coal down my pants . . . completely missed that one even though it was clearly stated in the first paragraph . . . one of the problems with reading a thread on Friday and not getting back to it until Tuesday.

Oops . . . then I stand by my words . . . as long as you're within the clearances stated by the manufacturer I believe you should be golden.
 
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