Need some help with Fireview hearth requirements

[Philbo]

I'm a bit confused. I'm working on gathering all the info and materials I need to build a hearth for our new/refurbished Fireview (coming in a couple weeks.)

I've referred to the installation section of the Fireview owner's manual, which I will copy and paste here for reference...

"If you decide to build your own hearth to go over a combustible floor, start with a plywood base. Over this apply:
1) a layer of 24 gauge galvanized sheetmetal,2) a 1/2 inch layer of an approved non-combustible insulation board (such as
DUROCK cement board or WonderBoard Backer Board),3) decorative non-combustible material such as tile, slate, stone or brick."

I don't know what R value the 24 ga sheetmetal has, but a 1/2" piece of Durock seems to have an R value of around 0.25. The decorative stuff as the final layer will add very little R value.

So to add to the confusion, I feel like I keep reading on this forum that the Fireview needs an R value of 1.2 underneath. I've been scrambling with no luck to try and source Micore, without ordering it online for $100 for double the amount I really need.

I will likely call Woodstock in the morning to confirm what the manual says.

This will be a slightly raised hearth on top of a hardwood floor. I plan to put down a 4'x5' piece of 3/4" plywood, whatever cement/ceramic board that's need for require R value, then a top layer of broken up/mosaic of 1" marble/granite on top with mortar to hold it all together.

Any thoughts?

Thanks!

 

[fox9988]

Hmmm. I couldn't find R-value requirement. I don't think there is one, just a suggestion to over-kill a noncombustible hearth.? A call to WS will answer your questions. Let us know what they say.

 

[Woody Stover]

A call to WS will answer your questions. Let us know what they say.

I'd like to hear their response, as well. They have a heat shield for the bottom of the Fv, too. I wonder if that reduces the requirement?

 

[Oldhippie]

Welcome Philbo and congrats in the Fireview!

 

[Backwoods Savage]

Welcome to the forum Phil.

By all means, you should feel free to call Woodstock on this. I did not follow the instructions you posted but not too far off. We also put a heat shield on the bottom and rear of the stove. Under the stove it get warm but not hot. It is a great place for us when we want gloves dried. As stated, it gets warm under there but never hot.

 

[fire_man]

"If you decide to build your own hearth to go over a combustible floor, start with a plywood base. Over this apply:
1) a layer of 24 gauge galvanized sheetmetal,2) a 1/2 inch layer of an approved non-combustible insulation board (such as
DUROCK cement board or WonderBoard Backer Board),3) decorative non-combustible material such as tile, slate, stone or brick."

So to add to the confusion, I feel like I keep reading on this forum that the Fireview needs an R value of 1.2 underneath. I've been scrambling with no luck to try and source Micore, without ordering it online for $100 for double the amount I really need.

By all means call WS, but I think you will be told the sheet metal is in case the top decorative layer is not solid. A grouted/mortared tile would be considered solid. The sheet metal is certainly not for R value. I am not aware of an "R" value defined by WS for the Fireview's hearth. 1/2" Wonderboard is only R=0.26, so the 1.2 your are reading is much better than WS recommends.

 

[Philbo]

Ok, I talked to Lorin today at Woodstock. She told me that they are in the process of re-writting their installation instructions in the manual and that, as some have said here, the sheet metal is an older method that's only advised if the top layer of the hearth is not solid.

We talked a bit about Micore and how hard it is to source. She said that, if pressed to give an R value, then she would say 0.59 for the Fireview. It was unclear if they are planning on changing the installation instructions soon or not, but she agreed that a defined R value makes installation a little more clear.

Knowing this now, I plan to use 2 1/2" layers of Durock + a layer of 1" granite with grout for an R value pretty close to the 0.59, maybe a tad under. I really don't want to spend $115 to buy micore online (have to wait for it to be shipped), then have half of it leftover.

Hopefully this will help some others who are in a similar situation.

 

[fire_man]

R = 0.59 for the Fireview makes sense. The Progress with long legs and no ashlip requires R = 0.40, and I can tell you from experience with both stoves, the Fireview heats the floor in front of the stove more than the Progress.

I cannot understand why the Fireview manual says go with 1/2" cement board (like Wonderboard) and a top layer such as tile, but that adds up to something like 0.26 + 0.02 = 0.28 which is not as good as 0.59.

 

[Backwoods Savage]

Ok, I talked to Lorin today at Woodstock. She told me that they are in the process of re-writting their installation instructions in the manual and that, as some have said here, the sheet metal is an older method that's only advised if the top layer of the hearth is not solid.

We talked a bit about Micore and how hard it is to source. She said that, if pressed to give an R value, then she would say 0.59 for the Fireview. It was unclear if they are planning on changing the installation instructions soon or not, but she agreed that a defined R value makes installation a little more clear.

Knowing this now, I plan to use 2 1/2" layers of Durock + a layer of 1" granite with grout for an R value pretty close to the 0.59, maybe a tad under. I really don't want to spend $115 to buy micore online (have to wait for it to be shipped), then have half of it leftover.

Hopefully this will help some others who are in a similar situation.

By all means, forget the micore. It is too difficult to find and then too difficult to pay for.

 

[charly]

So are you saying the specs I built my hearth pad to in the Fireview manual are not right? I did the 3/4 ply, 24 gauge sheet metal, 1/2 in durarock, the real cut brick with mortared joints. With the mortared joints I realized I didn't need the sheet metal but did it as simple overkill... Wow , what about the Progress now? I thought I was good to go even with the Fireview...

 

[begreen]

Ok, I talked to Lorin today at Woodstock. She told me that they are in the process of re-writting their installation instructions in the manual and that, as some have said here, the sheet metal is an older method that's only advised if the top layer of the hearth is not solid.

We talked a bit about Micore and how hard it is to source. She said that, if pressed to give an R value, then she would say 0.59 for the Fireview. It was unclear if they are planning on changing the installation instructions soon or not, but she agreed that a defined R value makes installation a little more clear.

Knowing this now, I plan to use 2 1/2" layers of Durock + a layer of 1" granite with grout for an R value pretty close to the 0.59, maybe a tad under. I really don't want to spend $115 to buy micore online (have to wait for it to be shipped), then have half of it leftover.

Hopefully this will help some others who are in a similar situation.

The original Durock was R=.26, but you can't get it anymore. Durock NexGen is the only usable USG cement board product you can buy now. It has an R value of .39. Two layers will have you well over the R=.59 requirement.

 

[fire_man]

Durock NexGen is the only usable USG cement board product you can buy now.

I don't understand this comment: Durock NexGen is the only usable USG cement board product you can buy now.

Are you saying Durock NexGen is the only cement board product you can buy now produced by USG?

"USG is North America's leading producer of gypsum wallboard, joint compound and a vast array of related products for the construction and remodeling industries."

• USG makes SECUROCK® and Durock®

There are other brands of "usable" cement board, although the R value may not be as good as the NexGen.

 

[begreen]

USG makes a couple of cement board products - Durock NexGen and another designed for showerpans and wet areas. I forget its name right now. The other product is with styrofoam beads and unsuitable for hearths. Securock is a gypsum/cellulose product. There are other companies that make cement boards. Wonderboard and Hardibacker are two other examples, but they are not made by USG.

 

[charly]

The original Durock was R=.26, but you can't get it anymore. Durock NexGen is the only usable USG cement board product you can buy now. It has an R value of .39. Two layers will have you well over the R=.59 requirement.

So is my hearth now under built because I followed Woodstocks hearth build specs? Were their specs wrong?

 

[begreen]

Ask Woodstock.

 

[charly]

Ask Woodstock.

For sure...

 

[mepellet]

The original Durock was R=.26, but you can't get it anymore. Durock NexGen is the only usable USG cement board product you can buy now. It has an R value of .39. Two layers will have you well over the R=.59 requirement.

Did you get a response from USG about durock nextgen?

https://www.hearth.com/talk/index.php?posts/1483618

Last I heard it technically was not approved for hearth use.

 

[begreen]

None yet. For sure I will report it when I hear from them.

 

[Philbo]

Just finished up laying the stone for my hearth this afternoon. I still have some work to do with adding trim around the base. I will likely match it to whatever trim I decide to use for the threshold, as we took part of a wall out partially to build this hearth.

I'm happy with how it turned out, considering this is my first attempt at stone work. Pics are chronological from when we bought the house a couple months ago.

I'll update when I get the stove setup and installed! Anybody got any good ideas/pics of useful shelving or racks that I could build and put to the right of my hearth to store things like kindling, gloves, fire tools, etc?

 

[Philbo]

Last 3

 

[charly]

Ask Woodstock.

Called Jamie today... With my new PH and optional ash lip , I'm good to go.. Thought at first I was looking at a now worthless 500 dollar hearth pad build.... So apparently I was under specs when I had the Fireview installed, but I did follow the requirements in the Fireview manual which stated only one 1/2 inch sheet of Durarock. Would have been sick to have to build another hearth when just a second sheet was needed...

 

[charly]

Just finished up laying the stone for my hearth this afternoon. I still have some work to do with adding trim around the base. I will likely match it to whatever trim I decide to use for the threshold, as we took part of a wall out partially to build this hearth.

I'm happy with how it turned out, considering this is my first attempt at stone work. Pics are chronological from when we bought the house a couple months ago.

I'll update when I get the stove setup and installed! Anybody got any good ideas/pics of useful shelving or racks that I could build and put to the right of my hearth to store things like kindling, gloves, fire tools, etc?
View attachment 107740
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I would have staggered { put the second short piece at the other end} the masonry board joints as to prevent any fine cracks from showing up on the finished surface. Probably be OK , but just for the sake of doing all that work... Looks great..

 

[Philbo]

Good tip. What's done is done now, but if I ever do it again I'll remember that. Thanks!

 

[fire_man]

It's definitely worth double checking the most up-to-date installation manual for your stove. The old Palladian manual (still on WS website) has no stated Hearth "R" value requirement. The updated manual requires R = 0.59.

I would have been REALLY bummed if I built my hearth based on the on-line manual, before the stove arrived with the new manual!

OLD MANUAL:



NEW MANUAL: