Hopefully, one final hearth building question

[TNCave]

Thanks already for all the help, I'm really trying to make sure I'm installing my stove safely.
I'm installing a Napoleon EPA 1100. I'd like to build my own mortared stone hearth pad, but am unsure how to do it safely.

The manual states: "If the stove is to be installed on a combustible floor, it must be placed on an approved non-combustible hearth pad."

The hearth pad will be placed directly on top of hardwood floor. Does this mean that as long as it's non-combustible I'm good, or do I need to strive for that 1.25 r value I've read about.

The nearest I can source Micore is over an hour drive. Thanks to this board, I found out that all I've read about Durock doesn't apply to the current next generation product where hearth construction is concerned.
I really need something that is available in 4x4 or 4x8 sizing, but if I'm only doing one layer, I could get by with the 3x5.

If I need to have the insulating R-value, I sure could use some suggestions.
If I don't, that would certainly be good information as well.

Thanks again for all your help.

Cory

 

[IndianaTech]

One layer of Micore depending on which you can get (160 or 300) has a R value of 1.2, so essentially if you layed that down on your hardwood floor, and put your stove on top of that (which you can not do, since Micore is very soft) you would have just enough R value. If it were me, I would get you a sheet of Micore (4 x 8) cut it in half, then cover that with atleast one layer of Durock so your mortar has something to stick to, and your stove won't push through the top layer. Let me know if you need anymore help, and good luck !!

 

[CountryBoy19]

One layer of Micore depending on which you can get (160 or 300) has a R value of 1.2, so essentially if you layed that down on your hardwood floor, and put your stove on top of that (which you can not do, since Micore is very soft) you would have just enough R value. If it were me, I would get you a sheet of Micore (4 x 8) cut it in half, then cover that with atleast one layer of Durock so your mortar has something to stick to, and your stove won't push through the top layer. Let me know if you need anymore help, and good luck !!

Uh.... I could be mistaken, but I think you're way off base.

I'm not familiar with the stove and requirement so I'm going by the info he gave.

Given the info he provided all he needs is a non-combustible surface. He doesn't need micore at all. He could just put down a subfloor of some sort to support his tile/brick properly then lay the brick.

 

[fossil]

...The manual states: "If the stove is to be installed on a combustible floor, it must be placed on an approved non-combustible hearth pad."...

If that's what the manufacturer's documentation for your appliance says, then that's all that's required...non-combustible ember protection. No specified insulative property (r-value) requirement. So long as whatever's between your stove and the combustible materials beneath the hearth pad you build are non-combustible, you're good to go. Just be sure to observe all the required footprint dimensions to the sides, front and rear of the stove. Different stoves have their own unique requirements, depending on the stove design and configuration, whether or not their pedestal or leg mounted, or have an ash pan under the firebox, and on and on. The requirements come from measuring the hearth temperatures beneath the stove during lab testing/certification. Rick

 

[IndianaTech]

Must have misunderstood, I thought he needed to meet a specific R value. I thought he was asking about building his own hearth pad, guess not ! My apologies

 

[TNCave]

Whew, well that makes things a lot easier.

Thank you all.

Cory

 

[CountryBoy19]

Must have misunderstood, I thought he needed to meet a specific R value. I thought he was asking about building his own hearth pad, guess not ! My apologies

Ah, I see what you were thinking. No problem; sorry if my post sounded harsh. I thought you were recommending that he use micore even though he doesn't need it. Micore is a pain to work with and still get a solid sub-floor for the tile/brick so I would avoid it if possible.

 

[sksmass]

Ah, I see what you were thinking. No problem; sorry if my post sounded harsh. I thought you were recommending that he use micore even though he doesn't need it. Micore is a pain to work with and still get a solid sub-floor for the tile/brick so I would avoid it if possible.

Countryboy19, when you say Micore is a pain to work with, can you elaborate on that? I am about to embark on a hearth build. My plan was to do 3/4" Micore, covered with 1/2" Durock (Old Gen), and then mortar and tile. Do you think I'll run into problems down the road? I don't want to have to do this twice.

 

[firefighterjake]

Thanks already for all the help, I'm really trying to make sure I'm installing my stove safely.
I'm installing a Napoleon EPA 1100. I'd like to build my own mortared stone hearth pad, but am unsure how to do it safely.

The manual states: "If the stove is to be installed on a combustible floor, it must be placed on an approved non-combustible hearth pad."

The hearth pad will be placed directly on top of hardwood floor. Does this mean that as long as it's non-combustible I'm good, or do I need to strive for that 1.25 r value I've read about.

The nearest I can source Micore is over an hour drive. Thanks to this board, I found out that all I've read about Durock doesn't apply to the current next generation product where hearth construction is concerned.
I really need something that is available in 4x4 or 4x8 sizing, but if I'm only doing one layer, I could get by with the 3x5.

If I need to have the insulating R-value, I sure could use some suggestions.
If I don't, that would certainly be good information as well.

Thanks again for all your help.

Cory

Random thoughts . . .

I'm not quite sure where you're getting that 1.25 R value since I quickly perused the 1100 manual on-line and all I can see is that Napoleon wants is a hearth that is non-combustible (for ember protection) with the proper size (namely, 8 inches all around and 19 inches in front.) If this is the case, a simple hearth built out of Durock, Wonderboard, etc. with stone or tile should suffice.

Durock . . . I posted some info on another thread . . . maybe I'm just confused . . . but it almost appears as though the new Durock can be used for a hearth as well as the old stuff . . . I am sure more folks will follow through on that thread and maybe we can come to a final consensus or figure out what is the right and what is wrong to use to build a hearth. At this point if I was to build a hearth I would try to get the old Durock, but barring that, myself personally . . . I would not have any heartburn in building with the newer stuff . . . at least until I learn/know more about what to use/not use.

3 x 5 sheets . . . I wouldn't let the size of whatever material you're looking at be a a problem. Most of the cement board products and Micore cut easily enough with a utility knife . . . you score and snap . . . and you can "bond" the two pieces together by fastening them and mortaring them to plywood and taping/mortaring the seam where the two pieces come together. On my own hearth I did just this -- took two pieces and attached/mortared them to plywood and then mortared the joint. Over this I mortared slate tile and grouted between the slate.

Micore . . . I haven't ever used Micore so take this advice with a grain of salt . . . however if I were to personally use Micore I think I would make a Micore sandwich . .. using a cement board product with the Micore mortared in between the two layers of cement board. I think this might help minimize flex and movement.

 

[CountryBoy19]

Ah, I see what you were thinking. No problem; sorry if my post sounded harsh. I thought you were recommending that he use micore even though he doesn't need it. Micore is a pain to work with and still get a solid sub-floor for the tile/brick so I would avoid it if possible.

Countryboy19, when you say Micore is a pain to work with, can you elaborate on that? I am about to embark on a hearth build. My plan was to do 3/4" Micore, covered with 1/2" Durock (Old Gen), and then mortar and tile. Do you think I'll run into problems down the road? I don't want to have to do this twice.

Well, I'll first admit that I've never actually worked with it. But I have handled it and I know what it is. It will almost crumble in your hands while handling it. So you need to be careful every step of the way not to crack, break crumble it. You have to be careful where you put it so it doesn't get bumped, banged, knocked around.

The main thing that I would be concerned about would be structural integrity for a tile job. Micore, being very soft, doesn't provide a solid surface, and durock isn't meant to be load-bearing on its own (it needs support underneath it for floor applications). Maybe multiple layers of durock would help but I'm not sure how many would be good. So with durock being flexible and micore being soft, if you lay porcelain tile over it you may end up with cracked tile. Just a word of caution.

That isn't a risk I wanted to go with so I just did 3 layers of durock to get the .8 R-value that I needed.

 

[ChillyGator]

...The manual states: "If the stove is to be installed on a combustible floor, it must be placed on an approved non-combustible hearth pad."...

If that's what the manufacturer's documentation for your appliance says, then that's all that's required...non-combustible ember protection. No specified insulative property (r-value) requirement. So long as whatever's between your stove and the combustible materials beneath the hearth pad you build are non-combustible, you're good to go. Just be sure to observe all the required footprint dimensions to the sides, front and rear of the stove. Different stoves have their own unique requirements, depending on the stove design and configuration, whether or not their pedestal or leg mounted, or have an ash pan under the firebox, and on and on. The requirements come from measuring the hearth temperatures beneath the stove during lab testing/certification. Rick

I used a piece of 3/8" tempered glass for ember protection, works great if you want to see the original flooring. I was concerned about steping on it at first but don't worry about it anymore.

 

[TNCave]

Thanks again for all the help.

The 1.25 R-value I dug up somewhere as a "standard" for hearth construction.
I just returned from Lowe's with the goods to build my hearth for ember protection only.
I did get some sheet metal for extra heat dispersion should I need it.

Best Wishes,

Cory

 

[chuckn]

Mine is currently underway....2x4 framed hearth on subfloor....then 5/8 inch plywood.....2 layers of durock.....mortast and 1 inch veneer stones.....trim it out...done. Back wall will be durock and stone as well.

 

[blackls1z]

Any pictures of the progress?