Hearth Renovation

[HomeinPA]

Thanks for clarifying the terminology. Yes, we've decided on veneer. The process does seem "easy", although I'm sure it will have challenges.

I like the idea of laying it out beforehand. We have an adjoining sunroom that would have enough floor space if we temporarily moved some furniture to lay out the full thing. I could do this well in advance over the next few weeks, to save us time on putting it together.

I don't have a notched trowel. I'll add that to my list of needed tools!

Honestly, forget laying it out somewhere. I had the same idea on the very first job I did.....complete waste of time. You leave to big of a gap somewhere and the entire layout is screwed. The best bet is to take an entire box or two of material and lay them out on a drop cloth or tables where you're working, separate sizes and put it together like a big jigsaw puzzle. That's just my experience though.

Are you going for a dry-stack look with ledge stone like in your photos or are you going to have a laid stone wall look with mortar joints? If you're doing dry-stack you will not be putting any mortar between the stones and you want them to fit as tightly as possible to each other. Just trowel some on the back and stick it and hold it in place for a few seconds.

 

[illini81]

Are you going for a dry-stack look with ledge stone like in your photos or are you going to have a laid stone wall look with mortar joints? If you're doing dry-stack you will not be putting any mortar between the stones and you want them to fit as tightly as possible to each other. Just trowel some on the back and stick it and hold it in place for a few seconds.

So we're actually a bit stuck on this question at the moment. The truth is we like both looks. We're trying to decide which we like better. I think we will end up with mortar joints, but I'm not positive yet.

 

[illini81]

So I am doing some reading on the clearance to combustibles requirements in my manual.

Mantel height requirement - 24" from top of stove, minimum. Won't be an issue.

Clearance to unshielded side wall - 10" minimum. I significantly exceed this.

Clearance from side of unit to edge of floor protection - 6" minimum. I will significantly exceed this.

Clearance from front of door opening to edge of floor protection - 16" minimum. I will make sure to significantly exceed this.

Questions:

1. For a flush hearth (0-2" raised), I need 1" thick non-combustible material with an R-value of 0.84. Does this mean that the full 1" of non-combustible material has to have an R-value of 0.84? Or just that the floor protection has to have a total R-value of 0.84 and has to be a minimum of 1" thick?

In other words, if I combined 1/2" of Micore 300 (R value 1.03) with 3/4" thick bluestone tile, would this be acceptable? Or do I need a full 1/2" of Micore, and then the tile on top of that?

2. Is there any trouble I can run into with the fireplace "wall" not being up to code? I am assuming there is simply brick behind the wood paneling, and so I will put up a scratch coat and then put up the stone (or however the manufacturer recommends it be installed), and this will be up to code? I can't find anything in the manual specifically about this.

Thanks!

 

[HomeinPA]

So I am doing some reading on the clearance to combustibles requirements in my manual.

Mantel height requirement - 24" from top of stove, minimum. Won't be an issue.

Clearance to unshielded side wall - 10" minimum. I significantly exceed this.

Clearance from side of unit to edge of floor protection - 6" minimum. I will significantly exceed this.

Clearance from front of door opening to edge of floor protection - 16" minimum. I will make sure to significantly exceed this.

Questions:

1. For a flush hearth (0-2" raised), I need 1" thick non-combustible material with an R-value of 0.84. Does this mean that the full 1" of non-combustible material has to have an R-value of 0.84? Or just that the floor protection has to have a total R-value of 0.84 and has to be a minimum of 1" thick?

In other words, if I combined 1/2" of Micore 300 (R value 1.03) with 3/4" thick bluestone tile, would this be acceptable? Or do I need a full 1/2" of Micore, and then the tile on top of that?

2. Is there any trouble I can run into with the fireplace "wall" not being up to code? I am assuming there is simply brick behind the wood paneling, and so I will put up a scratch coat and then put up the stone (or however the manufacturer recommends it be installed), and this will be up to code? I can't find anything in the manual specifically about this.

Thanks!

Since both materials are non-combustible and their combined thickness exceeds 1" and meets the required R value you should be fine.

If you're referring to the brick face of the fireplace, which is theoretically what's behind the paneling, there are specific requirements but 6" to either side and 12" above for the mantle are basically it. If you tear off the paneling and find framing then that's a bit different. All headers and framing are required to be 2" from the front of the fireplace (not the fireplace face though) and then you're going to have to put up a surface to mount the stone to. Hopefully you are potentially only putting a new face over the existing brick face. All depends on what's behind the paneling.

 

[rkofler]

Had stone done this past summer. Took 2 guys almost 2 full days, longer than i thought it might take. Probably depends on the stone you choose too. If you use strip or ledge they will fit together nice and easy. We like the look of some mosaic mixed in, so it was a pretty complex puzzle to fit together. They did have to cut quite a few pieces. Very happy with the end result, enjoying the insert even more this winter than last!!
Good luck, i'm sure you will be happy with whatever you choose!

 

[NoGoodAtScreenNames]

Clearance to unshielded side wall - 10" minimum. I significantly
1. For a flush hearth (0-2" raised), I need 1" thick non-combustible material with an R-value of 0.84. Does this mean that the full 1" of non-combustible material has to have an R-value of 0.84? Or just that the floor protection has to have a total R-value of 0.84 and has to be a minimum of 1" thick?

In other words, if I combined 1/2" of Micore 300 (R value 1.03) with 3/4" thick bluestone tile, would this be acceptable? Or do I need a full 1/2" of Micore, and then the tile on top of that?

Thanks!

Be careful with the floor R value requirement. I think the manual defines a required K value not R. There’s some formula to convert it that you can look up but they aren’t the same thing.

If I remember correctly K measures heat transmission so a lower number is better, while a higher R value is better.



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[illini81]

Had stone done this past summer. Took 2 guys almost 2 full days, longer than i thought it might take. Probably depends on the stone you choose too. If you use strip or ledge they will fit together nice and easy. We like the look of some mosaic mixed in, so it was a pretty complex puzzle to fit together. They did have to cut quite a few pieces. Very happy with the end result, enjoying the insert even more this winter than last!!
Good luck, i'm sure you will be happy with whatever you choose!

Beautiful! I love the varying sizes and shapes.

 

[illini81]

Be careful with the floor R value requirement. I think the manual defines a required K value not R. There’s some formula to convert it that you can look up but they aren’t the same thing.

If I remember correctly K measures heat transmission so a lower number is better, while a higher R value is better.



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Thanks! I now remember getting tripped up on R vs K in the past. I just found the helpful hearth.com article on R and K: https://www.hearth.com/talk/threads/wood-k-values-what-does-it-all-mean.147717/

Looks like 1/2" of Micore 300 provides a K factor of 0.84, which is what my stove requires. So I think 1/2" micore with tile or stone on top should be acceptable.

 

[NoGoodAtScreenNames]

Thanks! I now remember getting tripped up on R vs K in the past. I just found the helpful hearth.com article on R and K: https://www.hearth.com/talk/threads/wood-k-values-what-does-it-all-mean.147717/

Looks like 1/2" of Micore 300 provides a K factor of 0.84, which is what my stove requires. So I think 1/2" micore with tile or stone on top should be acceptable.

I’d be interested in your results. I’ve been thinking about doing something so I don’t need the temporary hearth extension. I wonder how hot the the material on top of the micro gets. The Micore would protect the house but does the tile / stone on top get too hot to touch?


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[illini81]

I’d be interested in your results. I’ve been thinking about doing something so I don’t need the temporary hearth extension. I wonder how hot the the material on top of the micro gets. The Micore would protect the house but does the tile / stone on top get too hot to touch?

I'll make sure to post lots of pics, as well as any trouble I run into along the way.

I'm probably misunderstanding what you are getting at, but neither the current stone hearth that I have, nor the stone hearth extender that I have in front of the hearth, get too hot to touch. I don't see why a new hearth would be any different?

 

[NoGoodAtScreenNames]

I'll make sure to post lots of pics, as well as any trouble I run into along the way.

I'm probably misunderstanding what you are getting at, but neither the current stone hearth that I have, nor the stone hearth extender that I have in front of the hearth, get too hot to touch. I don't see why a new hearth would be any different?

That’s what I was getting at. I have two rows of brick before dropping off to the hearth extender. The brick gets pretty hot. I was wondering if it would be uncomfortable for people / pets walking by on the hearth depending on the material used.


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[illini81]

Ok I am confused - what am I doing wrong here? This website (broken link removed) says that a 1/2" Micore 300 board has an R-value of 1.03.

If I convert this to K value using the equation K = thickness/R, I get (1/2")/(1.03) = 0.485.

However, the table in this hearth.com thread: https://www.hearth.com/talk/threads/wood-k-values-what-does-it-all-mean.147717/ says that 1/2" of Micore 300 has a K value of 0.84. Which is correct? Or am I screwing up the math somehow?

 

[illini81]

Also... is there any Micore variant that is sold in the big box stores? Just did a quick google search for Micore 300, and it seems like I can get it on Amazon and a few other places online, but I'm not seeing anywhere I can drive to pick it up. I'm hoping to start this project next Monday, and so I want to make sure I can get it in time.

 

[begreen]

Questions:

1. For a flush hearth (0-2" raised), I need 1" thick non-combustible material with an R-value of 0.84. Does this mean that the full 1" of non-combustible material has to have an R-value of 0.84? Or just that the floor protection has to have a total R-value of 0.84 and has to be a minimum of 1" thick?

Going by the manual, it specifies 1" thick material with a K-value of .84, not R-Value. This is pretty standard, the equivalent R-value is 1.19.


If unit is raised 0” - 2” (0mm-51mm); 1” (25mm) non-combustible material with k value = 0.84 or equivalent.

Check with local lumber and builder's supply houses to see if they carry micore.

 

[illini81]

Going by the manual, it specifies 1" thick material with a K-value of .84, not R-Value. This is pretty standard, the equivalent R-value is 1.19.

View attachment 242471
If unit is raised 0” - 2” (0mm-51mm); 1” (25mm) non-combustible material with k value = 0.84 or equivalent.

Check with local lumber and builder's supply houses to see if they carry micore.

Thanks. So I will need a full 1" of Micore. That means I will have 1" of Micore + 1" of stone on top of that + whatever the thickness is of the mortar... that puts me at maybe 2.5", and that will be next to 0.75" thick wood flooring. Is there any way to reduce the height of the micore/mortar/stone stack below 2.5"?

 

[begreen]

Add 1/2". You'll want some cement board on top of the micore for a decent bond.

 

[illini81]

Got it. So then 3" is about the minimum profile?

 

[begreen]

1/2" of Micore will suffice. 1/2" Micore 160 is R 1.2 and Micore 360 is R 1.1. Close enough. You could use a thinner stone tile instead of 1" stone. There are some nice ones in 1/4 and 3/8" thickness. So 1/2" + 1/2" + 1/4" would probably be the minimum.

 

[illini81]

1/2" of Micore will suffice. 1/2" Micore 160 is R 1.2 and Micore 360 is R 1.1. Close enough. You could use a thinner stone tile instead of 1" stone. There are some nice ones in 1/4 and 3/8" thickness. So 1/2" + 1/2" + 1/4" would probably be the minimum.

Got it, thanks!

 

[illini81]

Add 1/2". You'll want some cement board on top of the micore for a decent bond.

I noticed that there is 0.25" cement board. Is it acceptable to use that instead of 1/2" cement board, or is that going to be too flimsy? Just wondering because if I can use 0.25" cement board, then the height of the cement board and micore beneath it will be a total of 0.75", and then I might be able to get away without needing a transition piece at the front of the stone.

If I go with 1/2" cement board, then I would have a total cement board/micore height of 1", and so the cement board will be visible underneath the stone, since the hardwood flooring is 0.75" thick.

 

[begreen]

1/4" is pretty fragile. Would this be with 1" stone on top? Is this a stone slab or stone tiles?

Would putting a quarter round border trim around the hearth be out of the question?

 

[illini81]

1/4" is pretty fragile. Would this be with 1" stone on top? Is this a stone slab or stone tiles?

Would putting a quarter round border trim around the hearth be out of the question?

I think 1" stone, although we're not entirely decided. We will probably end up using some sort of transition piece, but I'd like it to be as small as possible.

 

[illini81]

I am not sure what I will find behind the wood paneling when I tear it down tomorrow. If it is block or brick, I will simply put up a scratch coat, and then the stone. However, if it is drywall, would it be acceptable to put up that metal mesh stuff and then a scratch coat and the stone? Does that meet code requirements?

From skimming the manual, it seems like the wall behind the stove simply needs to be non-combustible, which the stone will of course be. Just wanted to make sure that’s acceptable and that I don't need to meet some sort of R-value.

 

[illini81]

Just now getting around to uploading pics. Thanks to everyone who provided input/advice!

 

[begreen]

That came out great!