Please help: Tile Question for my raised hearth & surround - I have added questions with regard to e

[njkev]

Hi group,
The 12x12 marble-tile my wife picked out for our hearth/surround is constructed of roughly 3/8" ceramic tile backing and 1/8" thick marble face. It is a new product at Lowes. Does anyone know or have an opinion how these would hold up. I am sure these are better with regard to overall strength compared to straight marble. However, I am more concerned with cracking and/or separation of marble material when exposed to heat from the fireplace.

 

[EatenByLimestone]

Since it's a new product, the only way I can think to test it is to buy a square and put a propane torch to a corner of it. After using up a small bottle you should know how it will react to a few years of life under a woodstove. The corner should show if any delamination is going to occur.


Matt

 

[Elfin]

I'd be extremely concerned about this product. Marble is so fragile to begin with... when used as a veneer it is certain to chip, even if the whole tile doesn't crack through. Even ceramic can be very fragile, it really depends.

The best thing to do is check the PEI rating, if it has one... do you have any idea what the product is called? How much it is a square foot?

PEI I Tiles suitable for interior wall application.
PEI II Tiles suitable for residential bathrooms where softer footwear is worn.
PEI III Tiles suited to general residential traffic, except kitchens, entrance halls, and other areas subjected to continuous heavy use.
PEI IV Tiles suited for all residential and light to medium commercial areas.
PEI V+ Tiles suitable for heavy traffic and wet areas where safety and maximum performance are a major concern such as exterior hallways, food service, salad bars, building entrances, around swimming pools or shopping centers.

 

[njkev]

Elfin...I was mistaken about it being "marble". It is really polished "granite". The product is called "Stone Fusion" by Armstrong, and sold (just recently) at Lowes. The stuff was listed at a EI rating of 5 (at Lowes). The Armstrong web-site has NOTHING about this product.

Now...about my extended hearth. BTW....my Heatilator Constitution fireplace is raised 8 3/4. I intend to raise a 24"-deep extended hearth roughly 8". I had planned to use two sheets of 1/2" Durock, and 1/2" stone/ceramic tile over a 2"x6" frame. However, the manual states that I require a K-value of 0.43! The raised extended hearth will be 11" below the bottom of the firebox door. In addition, I have two 160cfm fans sucking room air below the door at 9" above the proposed extended hearth. I placed a "temporary" structure of block and marble slab at the proposed height for my permanent hearth as a test. I had that fireplace burning nice & hot for over 18 hours, and that marble slab was COOL to the touch!! Why specify such a low K-value (0.43) if the extended hearth doesn't get hot??? I think I would notice a pile of red-hot coals or a flaming log sitting on my extended hearth! If I read the R - K Value Chart correctly on this site, the 11" of AIR should give me an EXTREMELY low K-value! Someone please enlighten me! Are the Manufacturer specs. overkill?? I understand the 1" of non-combustible requirement....BUT not the K-value for my application.

thanks,
kev

 

[branchburner]

I don't understand the k-values needed for certain stoves, either. Some require only ember protection, some a huge amount of insulation.
But whatever the reason(s), best to follow any specs, no matter the overkill. Just for code and insurance purposes, I suppose, if not actual safety.

 

[njkev]

I don't understand the k-values needed for certain stoves, either. Some require only ember protection, some a huge amount of insulation.
But whatever the reason(s), best to follow any specs, no matter the overkill. Just for code and insurance purposes, I suppose, if not actual safety.

The bottom of the fascia (steel face) by the intake fans remains COOL TO THE TOUCH while the top of the fascia (and about 1 inch of the micore above DOES indeed get hot as hell!

BTW.....I asked the Heatilator company simply, "WHY such a LOW K-Value for the Constitution when the firebox door is 11 inches above the extended hearth (not to mention two 160cfm sucking cool room air?" . Their (unbelievable) response was "Because it has doors, and is not an open fireplace." It figures that I would get some NON-TECHNICAL person that does not have a "freaking" clue what a K-Value IS! I responded back explaining what K-Value IS, and the fact that I do not intend to BUILD A CAMPFIRE ON MY HEARTH!

Kev

P.S. Sorry.....I SHOULD have stated earlier that I am describing a ZC Fireplace, and NOT a wood stove application!!

 

[scotsman]

Elfin...I was mistaken about it being "marble". It is really polished "granite". The product is called "Stone Fusion" by Armstrong, and sold (just recently) at Lowes. The stuff was listed at a EI rating of 5 (at Lowes). The Armstrong web-site has NOTHING about this product.

Now...about my extended hearth. BTW....my Heatilator Constitution fireplace is raised 8 3/4. I intend to raise a 24"-deep extended hearth roughly 8". I had planned to use two sheets of 1/2" Durock, and 1/2" stone/ceramic tile over a 2"x6" frame. However, the manual states that I require a K-value of 0.43! The raised extended hearth will be 11" below the bottom of the firebox door. In addition, I have two 160cfm fans sucking room air below the door at 9" above the proposed extended hearth. I placed a "temporary" structure of block and marble slab at the proposed height for my permanent hearth as a test. I had that fireplace burning nice & hot for over 18 hours, and that marble slab was COOL to the touch!! Why specify such a low K-value (0.43) if the extended hearth doesn't get hot??? I think I would notice a pile of red-hot coals or a flaming log sitting on my extended hearth! If I read the R - K Value Chart correctly on this site, the 11" of AIR should give me an EXTREMELY low K-value! Someone please enlighten me! Are the Manufacturer specs. overkill?? I understand the 1" of non-combustible requirement....BUT not the K-value for my application.

thanks,
kev

If it's really polished (natural) granite, watch it carefully. Granite is mostly an amalgamation of dark, light and "in-between" component materials (quartz, feldspars and ferro-magnesians), which absorb heat at different rates and thus expand and contract at different rates. This expansion differential can cause the stone to crack (as it does in nature from exposure to sunlight, freezing, thawing, and so on) and compromise the stone as a heat barrier. If it's a manufactured "stone" and somewhat homogenous in color, it may resist the tendency to crack, but, as with all unproven materials, careful monitoring is the order of the day.

 

[njkev]

Elfin...I was mistaken about it being "marble". It is really polished "granite". The product is called "Stone Fusion" by Armstrong, and sold (just recently) at Lowes. The stuff was listed at a EI rating of 5 (at Lowes). The Armstrong web-site has NOTHING about this product.

Now...about my extended hearth. BTW....my Heatilator Constitution fireplace is raised 8 3/4. I intend to raise a 24"-deep extended hearth roughly 8". I had planned to use two sheets of 1/2" Durock, and 1/2" stone/ceramic tile over a 2"x6" frame. However, the manual states that I require a K-value of 0.43! The raised extended hearth will be 11" below the bottom of the firebox door. In addition, I have two 160cfm fans sucking room air below the door at 9" above the proposed extended hearth. I placed a "temporary" structure of block and marble slab at the proposed height for my permanent hearth as a test. I had that fireplace burning nice & hot for over 18 hours, and that marble slab was COOL to the touch!! Why specify such a low K-value (0.43) if the extended hearth doesn't get hot??? I think I would notice a pile of red-hot coals or a flaming log sitting on my extended hearth! If I read the R - K Value Chart correctly on this site, the 11" of AIR should give me an EXTREMELY low K-value! Someone please enlighten me! Are the Manufacturer specs. overkill?? I understand the 1" of non-combustible requirement....BUT not the K-value for my application.

thanks,
kev

If it's really polished (natural) granite, watch it carefully. Granite is mostly an amalgamation of dark, light and "in-between" component materials (quartz, feldspars and ferro-magnesians), which absorb heat at different rates and thus expand and contract at different rates. This expansion differential can cause the stone to crack (as it does in nature from exposure to sunlight, freezing, thawing, and so on) and compromise the stone as a heat barrier. If it's a manufactured "stone" and somewhat homogenous in color, it may resist the tendency to crack, but, as with all unproven materials, careful monitoring is the order of the day.

I will heed your advice. I noticed that the "darker" shade granite polished pieces are much smoother, and have a lot LESS of the smaller/lighter components. The ONLY place that I observed significant heat was right at the top edge of the fireplace. I will have to keep a spare box or two of these tiles around just in case!!