Soapstone or granite hearth?

[nojo]

I have a friend with a granite company. They owes me a few favors and said they would make me a hearth for my stove. Which I need. My stove is currently just sitting on some bricks.

Soapstone;

I like the dull, not shiney-ness of the material. It looks WAY better when its oiled. But dry its sort of too light and not dark enough. I think it would make a great hearth but Im worried about having an oiled surface under my stove, and aside form that, im sure the stove/ash would dry the oil out and it would look dry-spotty in parts.

Granite;
Granit is cool, it just comes polished and I think the polished shiny look would be too flashy...

Im jsut confused on what to do! I want to install this 30-NC asap.

 

[abd1]

what about honed granite? Its not polished and has a nice soft worn look like soapstone without needing oiling. I love soapstone too, not sure how the oil will react.

 

[Battenkiller]

Polished metallic surfaces have very low emissivity, so they don't radiate very much heat. I don't know about polished granite, but it is something you should look into if you want to use it to store heat to give off later. OTOH if it's just a looks thing...

 

[Bigg_Redd]

I have a friend with a granite company. They owes me a few favors and said they would make me a hearth for my stove. Which I need. My stove is currently just sitting on some bricks.

Soapstone;

I like the dull, not shiney-ness of the material. It looks WAY better when its oiled. But dry its sort of too light and not dark enough. I think it would make a great hearth but Im worried about having an oiled surface under my stove, and aside form that, im sure the stove/ash would dry the oil out and it would look dry-spotty in parts.

Granite;
Granit is cool, it just comes polished and I think the polished shiny look would be too flashy...

Im jsut confused on what to do! I want to install this 30-NC asap.

Can you politely request that the granite not be polished?

 

[Bigg_Redd]

Polished metallic surfaces have very low emissivity, so they don't radiate very much heat. I don't know about polished granite, but it is something you should look into if you want to use it to store heat to give off later. OTOH if it's just a looks thing...

Does the bottom of the stove get hot enough for this to matter?

 

[Slow1]

I wonder if you should consider the softness of the soapstone. I'm thinking during stove install or if you have to move the stove around (sliding feet etc). Even light things like stove tools (rake/poker, ash shovel, whatever) likely could scratch the surface.

Now, the good news is you can easily buff out these scratches with some steel wool, but each time you do you will be wearing away at the stone - if you wear the same areas it will eventually create pits.

I would expect it to take a LOT more to damage granite (probably chip it more likely than scratches unless it is polished highly).

Perhaps I'm off base here - folks use it for countertops and it works for them rather nicely.

 

[begreen]

I'd go with granite. It does not have to be polished. Advantages are a wide range of looks and colors, much denser, more stain and scratch resistant. Contact a granite countertop company that does unpolished surfaces to see the options.

http://www.marble.com/countertops/articles/1/Design/21/GraniteApplications.html

 

[Battenkiller]

Polished metallic surfaces have very low emissivity, so they don't radiate very much heat. I don't know about polished granite, but it is something you should look into if you want to use it to store heat to give off later. OTOH if it's just a looks thing...

Does the bottom of the stove get hot enough for this to matter?

Well, the cement floor in my basement gets so hot I can't stand on it in my bare feet directly in front of the stove. I've IR'd it at 135ºF after a full day of burning hot, and that's with no insulation below it. I also put paving blocks under my stove, and they get plenty warm.

I wouldn't use the bottom of a stove as an equal to the sides or top in calculating radiating surface areas, but it still emits plenty of heat. As well, the radiation also comes off at all angles, not just straight out. The hottest part of my floor is actually about eight inches from the leading edge of the front face.

There are specs for safe hearth thicknesses, etc., so there must be enough risk to codify them.

 

[Battenkiller]

I'd go with granite. It does not have to be polished. Advantages are a wide range of looks and colors, much denser, more stain and scratch resistant. Contact a granite countertop company that does unpolished surfaces to see the options.

http://www.marble.com/countertops/articles/1/Design/21/GraniteApplications.html

I'd go with unpolished granite myself, but I believe soapstone has the edge as far as both density and specific heat capacity. Not sure about black granite, though. Those precision black granite surface plates machine shops use are always being described as "high density granite".

 

[begreen]

The heat radiated beneath the stove will vary widely depending on the stove make and model. Hearth protection is specified by the manufacturer and must be followed regardless of the top of the hearth surface treatment.

 

[scotsman]

Polished metallic surfaces have very low emissivity, so they don't radiate very much heat. I don't know about polished granite, but it is something you should look into if you want to use it to store heat to give off later. OTOH if it's just a looks thing...

Does the bottom of the stove get hot enough for this to matter?

Well, the cement floor in my basement gets so hot I can't stand on it in my bare feet directly in front of the stove. I've IR'd it at 135ºF after a full day of burning hot, and that's with no insulation below it. I also put paving blocks under my stove, and they get plenty warm.

I wouldn't use the bottom of a stove as an equal to the sides or top in calculating radiating surface areas, but it still emits plenty of heat. As well, the radiation also comes off at all angles, not just straight out. The hottest part of my floor is actually about eight inches from the leading edge of the front face.

There are specs for safe hearth thicknesses, etc., so there must be enough risk to codify them.

Here's another consideration--
IF your "stone" is really "granite" it is composed of a variety of materials: ferro-magnesians (dark particles), quartz (clear or nearly so), feldspars (not necessarily light or dark), etc. There are zillions of "kinds" of granite, fine grained (Georgia Gray) to very coarse (Texas Pink and Stacia Rose). These different particles will absorb heat at different rates and expand and contract at different rates causing them to break apart physically. It will not matter if it's sealed or not or polished or not. In fact, non-polished surfaces will be more subject to heat degradation. It's just what will happen. Some won't be as prone to it at others. Small, fine-grained crystals will do better. Ones with the larger crystals will do worse. The process is called physical weathering and occurs outdoors where granite is exposed to the elements. The more homogenous stones (limestone, marble, etc.) will serve better than metamorphic types (granites, etc.). However, gabros, which are uniformly dark, but still composed of fairly large, but generally the same crystals, should fare much better in response to the heat, being the same color will expand and contract more "together". Warning, if you use a gabro or other dark stone (many people call these gabros "black granite", which they really aren't), be advised that it will be HOT to the touch and will remain so for many hours, which COULD be a good thing, just not to walk on with bare feet! Personally, if granite is the product they have and you want it, I'd get the finest grain stone possible. Otherwise I'd go for marble or the like. Marble is a soft metamorphic form of limestone, which does not do well outdoors, but is great indoors. There are many things to consider, such as thickness, etc. What I've related are the very basic initial considerations. Good luck.

 

[Battenkiller]

Good info, Texas boy.

 

[ckdeuce]

I wonder if you should consider the softness of the soapstone. I'm thinking during stove install or if you have to move the stove around (sliding feet etc). Even light things like stove tools (rake/poker, ash shovel, whatever) likely could scratch the surface.

Now, the good news is you can easily buff out these scratches with some steel wool, but each time you do you will be wearing away at the stone - if you wear the same areas it will eventually create pits.

I would expect it to take a LOT more to damage granite (probably chip it more likely than scratches unless it is polished highly).

Perhaps I'm off base here - folks use it for countertops and it works for them rather nicely.

Yep... To soft..... Scratch...... Regret ..... Go with another option. Even my stove top thermometer scratches my soap stone stove. Good luck and let us know how it turns out.

 

[Bobbin]

Soapstone is really, really soft as noted above. I'd go for the granite. You don't have to have it polished up like a tombstone, you know!

 

[Highbeam]

See if they can leave the edges of the granite slab, I vote granite BTW, rough vs. the perfectly rounded corners of a countertop.

 

[Battenkiller]

The heat radiated beneath the stove will vary widely depending on the stove make and model. Hearth protection is specified by the manufacturer and must be followed regardless of the top of the hearth surface treatment.

Ah yes, my bad. Here I am thinking everybody has a stove without an ash drawer like the one I have (and the one I had before this one).

For the record, I ran three IR scans of the bottom of my Vigilant today. The first with about an inch of coals on top of lots of ashes, the second about 1/2 an hour after emptying the ashes and refilling the stove and the last one just now with the fire fully involved. Got average temps across the bottom of 275º, 350º, and 425ºF, respectively. Warmer than I thought, which is probably why VC included a bottom heat shield with the stove (mine is off).

 

[begreen]

Yup. Even with our stove cranking at 650, the hearth underneath the stove is barely warm to the touch. Last time I measured it was something like 89 °F. Move out in front of the glass and it gets much warmer.

 

[nojo]

Wow guys thanks for all the replys!

They specialize in granite but they also have saopstone and marble. I will be getting these cut from remnants so it will mostly matter what is in stock or laying out on the pile. The specific kind of soapstone they have can not be worked dry and is very hard. I have a peice of it here that I will try to scratch reasonably.

Marble is very white.. does it come in dark colors? Also its softer than soapstone..

Also the granite they get is polished from the place the giant slabs are cut. Its all polished. Well the face of it is, the backside has saw marks in it.

 

[firefighterjake]

My vote is for granite . . . mainly due to concern over scratches . . . and if the company is using remnants I would guess they would have a lot more granite remnants kicking around to choose from vs. soapstone since around here at least there are far, far more folks requesting granite countertops.

Also, remember to check the stove's requirements for R value protection to make sure you're good to go with just the granite . . . or if you'll need to add more protection.

 

[nojo]

Also, remember to check the stove's requirements for R value protection to make sure you're good to go with just the granite . . . or if you'll need to add more protection.

Good point. I was thinking about this. Im sure granite transfers heat. Would it be smart to put some Durok under the granite? Or a metal sheet? The stove im installing is a NC 30 with pedestal so I think it does not matter. But I'd like to build it so that if we change stoves it will still provide adequate protection.

 

[Slow1]

Also, remember to check the stove's requirements for R value protection to make sure you're good to go with just the granite . . . or if you'll need to add more protection.

Good point. I was thinking about this. Im sure granite transfers heat. Would it be smart to put some Durok under the granite? Or a metal sheet? The stove im installing is a NC 30 with pedestal so I think it does not matter. But I'd like to build it so that if we change stoves it will still provide adequate protection.

What is under the hearth? The challenge it seems is that not knowing what you MIGHT put there in the future makes it really hard. Unless you have a completely non-combustible surface under the hearth you will be guessing. Now, the ultimate approach may be to survey all stoves out there (perhaps all current EPA stoves, I somehow doubt you would go with a non-EPA, right?) and find out what the greatest level of protection required is then build to that spec. I imagine in so doing you will be taking on a significant amount of trouble and perhaps even cost, but if you do the survey you may find a happy middle ground level to put in there.

Keep in mind though that if you are going that route, make sure that you are making it large enough in all directions too - that future stove may require greater clearances and have protection requirements that are wider around the edges too so you need to extend farther out now too "just in case"... (it never ends eh?)

Mind you I'm with you on wanting to be prepared for anything - I even considered going the "build up a good layer of protection just in case" route with my hearth pad build last summer, but after a bit of pondering I decided that it just wasn't worth the effort and cost for me. Everyone's situation is unique.

 

[nojo]

You may be right about that. I might just build it to the specs of this stove. Its on a tile floor, then a wooden frames hearth was built on top of that.

I cant find the required floor protection R value for the englander 30..

Also I have a masonry wall thimble. Do I need to protect the wall above it at all? Is this flue-type dependent? The local building inspector does not return my calls and is never in the office when I go down there. The fire department has no idea about the codes.

thanks!

 

[Slow1]

You may be right about that. I might just build it to the specs of this stove. Its on a tile floor, then a wooden frames hearth was built on top of that.

I cant find the required floor protection R value for the englander 30..

Also I have a masonry wall thimble. Do I need to protect the wall above it at all? Is this flue-type dependent? The local building inspector does not return my calls and is never in the office when I go down there. The fire department has no idea about the codes.

thanks!

I suggest opening a new thread with those questions. You will get a better response from those who actually know what they are talking about - they are here but may not be tracking this thread.

 

[begreen]

You may be right about that. I might just build it to the specs of this stove. Its on a tile floor, then a wooden frames hearth was built on top of that.

I cant find the required floor protection R value for the englander 30..

Also I have a masonry wall thimble. Do I need to protect the wall above it at all? Is this flue-type dependent? The local building inspector does not return my calls and is never in the office when I go down there. The fire department has no idea about the codes.

thanks!

From the manual http://www.englanderstoves.com/manuals/30-NC.pdf :

"There are many floor and wall board manufacturers, and you should be very cautious in choosing the proper protection. The type board you choose should be U.L. rated and listed. After examining the area you plan to place your stove and determining it requires a board, the next step is to select the proper size. The stove you choose will determine the size board that is required. The approved protector board should be large enough to provide a minimum of eight inches (8”) behind the unit, eight inches (8”) on either side and sixteen inches (16”) in the front where the door is located. The protection must have an R-value of 1.5 (English units) or equivalent (See “Installation on a Combustible Floor”). This stove requires a minimum 48” x 48” floor protection."
The granite will need some insulation between it and the wood framing.

The flue to ceiling clearance depends on the connector pipe. A minimum of 18" is required for single-wall, 6" for double-wall, but there's no harm in exceeding the requirement.

 

[nojo]

Would you guys put Concrete Backer broad under the granite?

I just ordered the granite slab. Skirt height will depend on whether we want backer board under it..

Total height of the hearth will be 9 inches... Does that sound reasonable?