Question about making a hearth pad

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johnnyvirgil

New Member
Jan 25, 2023
51
Upstate NY
This might be a dumb question, but I see a ton of how-to videos that use wooden edges on hearth pads. My question is, when the pad requirements say “eight inches to sides of stove,” I’m assuming that is for a 100% non-combustible pad, which means all these pads I see being made with wooden edges won’t be to code unless the wood is at least as far away as the stove’s required distance to combustible walls. Am I interpreting that incorrectly? Also, if the stove specs say .47 r-value (jotul 602 v2, for instance) how do I know what materials will be sufficient? On a tiled floor installed over wooden subfloor, would a layer of 1/2” cement board covered in 1/2” tile be sufficient? I was originally going to build it with an oak surround but now I’m thinking it might need to be angle iron or aluminum (ugly). Any advice? I don’t want to just buy one premade because the required footprint for the stove is 43 1/2” long by 28 1/2” wide and all the premade ones that meet the length requirements are way too wide. Thanks!
 
Many stove manuals list the R value of common hearth pad materials. And yes the trim needs to meet minimum distance to combustibles.

Microcore is a common material that is used to meet R value. Top down it would commonly be tile, cement board, microcore, plywood for the construction
 
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If at all possible, make the hearth pad a bit oversized. The distances are the minimums. Making it larger may come useful if the stove is changed out at a later date.
Two layers of cement board will get you to the R=.45 requirement for a Jotul F602 CB.
 
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Many stove manuals list the R value of common hearth pad materials. And yes the trim needs to meet minimum distance to combustibles.

Microcore is a common material that is used to meet R value. Top down it would commonly be tile, cement board, microcore, plywood for the construction
Very helpful, thank you. The pad manufacturers were telling me I would need something like 7 layers of cement board to get to R-1
 
Very helpful, thank you. The pad manufacturers were telling me I would need something like 7 layers of cement board to get to R-1
Actually, that would take 4 layers, or 3 using Durock NexGen cement board with perlite beads in it. But you mentioned R=.45.

 
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Actually, that would take 4 layers, or 3 using Durock NexGen cement board with perlite beads in it. But you mentioned R=.45.

Yes, I believe with the bottom shield that’s all that is required for the 602v2 but I wasn’t sure how to find out the relative r values of different materials and some of what I was seeing was wildly different. I eve resorted to asking chatGPT. The manual only had formulas that made my head spin just looking at them.
 
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Yes, I believe with the bottom shield that’s all that is required for the 602v2 but I wasn’t sure how to find out the relative r values of different materials and some of what I was seeing was wildly different. I eve resorted to asking chatGPT. The manual only had formulas that made my head spin just looking at them.
Yes, some of the explanations in manuals get too abstract for basic instruction. Hopefully, the link posted will prove helpful.
 
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It does, thanks. Since I have a tiled floor in the kitchen already, here's what Chat GPT had to say when I asked "what is the R-value of two layers of tile and one layer of cement board?" - Typically, ceramic tile has an R-value of about .7 per inch of thickness and cement board has an R-value of about .25 per inch. So if the tile is 1/4" thick, and the cement board is 1/2" thick, the combined R-value of two layers of tile and one layer of cement board would be approximately 1.45.

Also, here's the original chart from the hearth pad company I was questioning. It was 1.6, not 1.0
1676291466287.png


This is the info about the (odd) pad size, which is why I was thinking of making it.

A bottom heat shield is required in all installations and is included on the stove. In addition, the stove must be placed on a noncombustible surface that extends continuously 8” beyond the sides and back of the stove and 16” in the front of the stove(18” in Canada). This will result in an overall base that is 28 1/2” wide x 45- 1/2” deep . This is the minimum floor protector size. Floor protection must also be used under the stove pipe and must extend 2” beyond either side of the pipe (fig. 7, page 13).

The floor protection must have a minimum R value of 0.45. Warning! Never put any type of floor protection on top of carpeting.

Lastly, this is the "helpful" info in the manual
.
1676292589578.png
 
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Micore is the best R value bang for your thickness buck. My stove requires R=1 protection so I have a powdered steel Ember King extension with micore 160 cut to size underneath it. Works and IMO looks great. I like the simplicity, ease of cleaning, and durability of the powdered steel.

Micore is easy to find online or at a local construction supply. I got mine at Kamco. Had to buy a while 8x4 sheet but it was like $40 iirc and I gave half to a friend for his stove.

Excuse the messy picture, I'm recovering from surgery (I'm ok) and haven't felt like vacuuming this week!

Screenshot_20230213-075411.pngPXL_20230208_144211117.jpg
 
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It does, thanks. Since I have a tiled floor in the kitchen already, here's what Chat GPT had to say when I asked "what is the R-value of two layers of tile and one layer of cement board?" - Typically, ceramic tile has an R-value of about .7 per inch of thickness and cement board has an R-value of about .25 per inch. So if the tile is 1/4" thick, and the cement board is 1/2" thick, the combined R-value of two layers of tile and one layer of cement board would be approximately 1.45.

Also, here's the original chart from the hearth pad company I was questioning. It was 1.6, not 1.0
View attachment 309638

This is the info about the (odd) pad size, which is why I was thinking of making it.

A bottom heat shield is required in all installations and is included on the stove. In addition, the stove must be placed on a noncombustible surface that extends continuously 8” beyond the sides and back of the stove and 16” in the front of the stove(18” in Canada). This will result in an overall base that is 28 1/2” wide x 45- 1/2” deep . This is the minimum floor protector size. Floor protection must also be used under the stove pipe and must extend 2” beyond either side of the pipe (fig. 7, page 13).

The floor protection must have a minimum R value of 0.45. Warning! Never put any type of floor protection on top of carpeting.

Lastly, this is the "helpful" info in the manual
. View attachment 309639
LOL, that shows me that Chat-GPT is just making up chit. Lord help us when this tech takes over systems.
 
Micore is the best R value bang for your thickness buck. My stove requires R=1 protection so I have a powdered steel Ember King extension with micore 160 cut to size underneath it. Works and IMO looks great. I like the simplicity, ease of cleaning, and durability of the powdered steel.

Micore is easy to find online or at a local construction supply. I got mine at Kamco. Had to buy a while 8x4 sheet but it was like $40 iirc and I gave half to a friend for his stove.

Excuse the messy picture, I'm recovering from surgery (I'm ok) and haven't felt like vacuuming this week!

View attachment 309640View attachment 309641
I wouldn't mind using the micore, but I'd want to encapsulate it and finish the edge somehow. That stuff dusting all over the place is bad for your lungs. (or so I've read)
 
I wouldn't mind using the micore, but I'd want to encapsulate it and finish the edge somehow. That stuff dusting all over the place is bad for your lungs. (or so I've read)
There is no need to use micore on an ember protection only hearth.
 
I wouldn't mind using the micore, but I'd want to encapsulate it and finish the edge somehow. That stuff dusting all over the place is bad for your lungs. (or so I've read)
I'm not terribly concerned about any respiratory effects it may have. It's a very small exposed edge that doesn't seem much action underneath the powdered steel. I can't see that little amount being any worse for me than the occasional small amounts of smoke rollout on a reload. If you were concerned I'm sure there's an easy way with something like aluminum etc.
 
I'm not terribly concerned about any respiratory effects it may have. It's a very small exposed edge that doesn't seem much action underneath the powdered steel. I can't see that little amount being any worse for me than the occasional small amounts of smoke rollout on a reload. If you were concerned I'm sure there's an easy way with something like aluminum etc.
That's true. Probably just california warnings or something. The place where I picked up the stove today had some -- a 2x5 sheet was over $70.
 
Mine needs to have an R value of .45, and I'm leaning toward going with 2X cement board and a layer of tiles or brick veneer. Finishing the edge is the question.
Yes, and that's a good plan. You can use wood to picture frame the edges.
 
It does, thanks. Since I have a tiled floor in the kitchen already, here's what Chat GPT had to say when I asked "what is the R-value of two layers of tile and one layer of cement board?" - Typically, ceramic tile has an R-value of about .7 per inch of thickness and cement board has an R-value of about .25 per inch. So if the tile is 1/4" thick, and the cement board is 1/2" thick, the combined R-value of two layers of tile and one layer of cement board would be approximately 1.45.

Also, here's the original chart from the hearth pad company I was questioning. It was 1.6, not 1.0
View attachment 309638

This is the info about the (odd) pad size, which is why I was thinking of making it.

A bottom heat shield is required in all installations and is included on the stove. In addition, the stove must be placed on a noncombustible surface that extends continuously 8” beyond the sides and back of the stove and 16” in the front of the stove(18” in Canada). This will result in an overall base that is 28 1/2” wide x 45- 1/2” deep . This is the minimum floor protector size. Floor protection must also be used under the stove pipe and must extend 2” beyond either side of the pipe (fig. 7, page 13).

The floor protection must have a minimum R value of 0.45. Warning! Never put any type of floor protection on top of carpeting.

Lastly, this is the "helpful" info in the manual
. View attachment 309639
I cant believe people trust chatGPT. :)
 
I almost bought some but it was an odd size and I would have needed two to make my 28 1/2" x 45 1/2" pad.
Yeah. I had to buy a whole 4x8 sheet to make my pad. Ended up being enough for 5 pads but I was OK with that. Gave me some error insurance and I gave a friend a piece for his hearth. I'd give you the rest if you were closer! I'm kind of shocked how much it's gone up but also not at all given how construction prices have been the last few years.
 
Unfortunately, they get horrible reviews, so last night I bought everything to make one out of cement board and tiles.
It will outlast the stove!!
 
Yeah. I had to buy a whole 4x8 sheet to make my pad. Ended up being enough for 5 pads but I was OK with that. Gave me some error insurance and I gave a friend a piece for his hearth. I'd give you the rest if you were closer! I'm kind of shocked how much it's gone up but also not at all given how construction prices have been the last few years.
For my other stove, (a vermont castings Vigilant II coal stove - highly recommended btw) I bought a premade corner pad for about $300 roughly 7 years ago. The same pad is now over $650. I mean, I get inflation but sometimes I think companies just take advantage of it to raise their prices. "Well, inflation, pay up. "