r values?

[Andy99]

As you know I'm having a hearthstone homestead with the surround installed. IM sitting it on my fireplace hearth and running the stove pipe up the chimney. I have the 4 inch legs on the stove so the stove pipe will easily fit into the fire box. Now here is the problem. The place I'm getting the stove from does not seem concerned about the r-value and clearances. I want to make sure this will be safe for 24/7 burning. I'm going to sit the stove on my hearth. the hearth is raised about 4 inches and comes out 19 inches from the fireplace opening. Its a traditional brick hearth. I don't know what its sitting on but I have a basement. Now on top of the hearth I used thinset to glue on 5/8 inch thick granite tiles. Just past the hearth is hard wood floors. Now since the stove is sitting on the hearth its going to take up a good part of the 19 inches. Can I just put a semi circle hearth rug down over the hard wood floor or do I need something with an r-value? If I need something with an r-value is there anything I can put down that would be temporary and that I can take up in the summer when I'm not using the stove? I also have a mantel with legs. The side clearance is fine but from the top of the stove to the bottom of the mantel might be close but I find the spec on clearances on the homestead web site confusing when it comes to how high the mantel has to be off the top of the stove? Here is a picture so you can see what I have ....


what do you think???

 

[wellbuilt home]

The mantle looks close to me. It mite get cooked a little( turn brown) The floor should be ok but building code is 20" in front of stove for the harth . My dog would lay under my stove all day and she never burned up . Had some real dry skin

 

[Andy99]

I can raise the mantel about 6 -8 inches then I will have to build some kind of block to put under the legs to make them look finished and not floating off the floor...

 

[begreen]

You need to know what's under the hearth bricks. If wood, problem. If 6" of cement, maybe no problem. A hearth rug is not a heat shield. You'll need to honor the stove requirement for a hearth in front of the stove. This is where it radiates the most heat.

 

[Andy99]

You need to know what's under the hearth bricks. If wood, problem. If 6" of cement, maybe no problem. A hearth rug is not a heat shield. You'll need to honor the stove requirement for a hearth in front of the stove. This is where it radiates the most heat.

I went down in the basement and right under the fireplace there is a pc of plywood flush with the bottom of the beams and it seems to be filled with a type of concrete?

Is there are thing I can build using some of the extra granite tiles i have to put on the floor in front of the hearth that I can take up in the summer?

 

[webbie]

The stove manual should have an R-Value expressed for use with those 4" legs. Once you have that, you can work with it.....see if they sell an additional bottom heat shield.

Look at the basement under the fireplace area - sometimes you can see the bottom of the cement where it is poured in to create the hearth base. I have often seen plywood used on the bottom to "form this up".

The specs for the mantel should also be clearly stated in the manual.

The front hearth protection must also meet code - no hearth rug! There are UL approved hearth pads, or you can make up one yourself using matching tiles.

As to under the stove, your options are somewhat limited and you may have to talk to the factory folks......at first glance, it might work well if you have 8" plus of masonry (and I suspect you do) and then you make up a heat shield (24 ga sheet metal) which is somehow suspended 1/2 way between the stove bottom and the hearth. This will add tremendous R-Value to the assembly.

 

[webbie]

You need to know what's under the hearth bricks. If wood, problem. If 6" of cement, maybe no problem. A hearth rug is not a heat shield. You'll need to honor the stove requirement for a hearth in front of the stove. This is where it radiates the most heat.

I went down in the basement and right under the fireplace there is a pc of plywood flush with the bottom of the beams and it seems to be filled with a type of concrete?

Is there are thing I can build using some of the extra granite tiles i have to put on the floor in front of the hearth that I can take up in the summer?

OK, just as I suspected. Your hearth is probably 8-12" thick of various masonry materials. A conservative figure in terms of R-Value would be about 1.2, which I am sure is not enough for a stove on shorter legs. That said, this is not imminent danger. In fact, the existing fireplace was probably more dangerous than the stove, as heat transfer from that fire (direct on the hearth) could be more than the stove, which is protected by an airspace and the stove bottom etc. - Still, you want to be as safe as possible and up to factory spec.

I think the sheet metal shield will do the job, but you should confirm with the factory tech (Hearthstone is good with this stuff), and perhaps get a fax confirming this.

The hearth extension in front is lower, so the R-value can be less. The manual should also give an idea of this. You can definitely build an assembly which could be removed in the summer.

 

[STOVEGUY11]

The homestead has big clearances off of the top of it for mantel clearances. Off the top of my head I think its 36". You can use the optional surround and it cuts down to I think 22" or so. I usually have a tough time getting them in peoples fireplaces that have combustible mantels.

 

[Andy99]

I got this out of the owners manual.... How the hell does anyone get an r-value of 6.6! the hearth pad will have to be 2 feet thick....

Hearth extension with an "R"-value
and 8" beyond either side of the fuel and ash door openings.
of 2.5 or listed to U.L. 1618, extending 16" in front of glass

Non-combustible floor construction or floor protector
with an"R"-value of 6.6 beneath the stove.

You can make your own floor protector by stacking
together noncombustible materials from the following
table. Simply add together the listed R-values to attain the
necessary requirements for installing your stove.
Noncombustible Material Thickness R-value
Gypsum or plaster board1 1/2² 0.45
Wallboard, Wonderboard, or
Durock1
1/2² 0.20
Ceramic board (Fiberfrax or Micor)1 1/2² 1.10
Nominal solid clay brick1 1² 0.20
Ceramic wall or floor tile1 1/4² 0.01
Mineral wool insulation2 1² 3.12
Cement mortar2 1² 0.20
Horizontal still air2 * 1/8² 0.92
*Note: You cannot “stack” horizontal still air to accumulate
R-values; you must separate each layer of horizontal
still air with another noncombustible material.
To fabricate a floor protector for a wood floor with an
R-value of at least 2.5, consider the following examples:
½² ceramic board 1.10
1/8² horizontal still air 0.92
4² solid clay brick 0.80
Total R-value 2.82
½² mineral wool insulation 1.56
1/8² horizontal still air 0.92
1² cement mortar 0.20
Total R-value 2.68

 

[begreen]

Can we assume that this is for the 4" leg model? Agreed, that is a pretty high R value.

The most compact unit would probably be a metal framed cavity with sheet of durock on the bottom, then 2" of mineral wool, then another sheet of durock, a sheet of 28 ga metal, a sheet of durock and the stone or tile top.

 

[Andy99]

I just went to the store i ordered the stove from. They are also installing it and Asked if there was anyway we could use the unit with the 6 inch legs. Based on my measurements it would be tight but should work. Im waiting to hear back from them and to see if i can still change the order.

 

[begreen]

If 6" legs, then a bottom heat shield can be added and the hearth requirement drops to an easier to fabricate R 2.5. If you use 1" of micore, a sheet of metal, then 2 layers of durock or wonderboard and tile the top, you'd be there.

 

[Andy99]

I just heard back from the stove guy and he told me the current set up is fine of the stove with the 4 inch legs!
that my 6-8 inches of masonry is all i need. I told him I would really like a stove with the 6 inch legs and he is seeing what he can do...

 

[badger1968]

Hi Andy--
As you know, I'm putting in a Homestead as a hearth mount too. 4" legs. I was stunned by the 6.6 r-value required under the stove and 4" in front of the glass door. But as long as you have masonry and air underneath this footprint you are fine--as I believe is the case. Where I see a small problem is the 2.5 r-value you will need extending 12" beyond the 4" clearance from the glass door.
If your hearth is 19" from the opening, and you mount your Homestead flush with this opening then you have only 6" from the glass doors to your beautiful wood floor (Homestead is 13" deep). So, unless you partially recess the stove, you will need r 2.5 protection extending at least an additional 10" from the end of your hearth. I don't think you want to rip up that beautiful wood floor and extend the hearth, so I'd build a free-standing hearth extension (or buy a suitable hearth pad) to be used in the winter only with a 2.5 r-value.
Of course you could modify (shorten) these requirements by partially recessing the stove into the firebox.
I hope this makes sense and helps. Badger.

 

[Andy99]

Hi Andy--
As you know, I'm putting in a Homestead as a hearth mount too. 4" legs. I was stunned by the 6.6 r-value required under the stove and 4" in front of the glass door. But as long as you have masonry and air underneath this footprint you are fine--as I believe is the case. Where I see a small problem is the 2.5 r-value you will need extending 12" beyond the 4" clearance from the glass door.
If your hearth is 19" from the opening, and you mount your Homestead flush with this opening then you have only 6" from the glass doors to your beautiful wood floor (Homestead is 13" deep). So, unless you partially recess the stove, you will need r 2.5 protection extending at least an additional 10" from the end of your hearth. I don't think you want to rip up that beautiful wood floor and extend the hearth, so I'd build a free-standing hearth extension (or buy a suitable hearth pad) to be used in the winter only with a 2.5 r-value.
Of course you could modify (shorten) these requirements by partially recessing the stove into the firebox.
I hope this makes sense and helps. Badger.

I can fit the one with the 6 inch legs I just didn't know i could. I have 25 inch from the hearth to the top of the fireplace opening. SO the one with the 6 inch legs will work. The problem is the stove store already ordered me the one with 4 inch legs so now They are trying to change it. I think that since they are the pros and Im just a home owner they should have known all this I brought in detailed diagrams when i bought the stove and they sent someone to my house to measure. If i never bothered to download the pdf with the specs off of hearthstones web site I would have a stove that is unsafe in my house...

 

[begreen]

You'll also need to be sure that it has the bottom heat shield.

 

[badger1968]

I can fit the one with the 6 inch legs I just didn’t know i could. I have 25 inch from the hearth to the top of the fireplace opening. SO the one with the 6 inch legs will work. The problem is the stove store already ordered me the one with 4 inch legs so now They are trying to change it. I think that since they are the pros and Im just a home owner they should have known all this I brought in detailed diagrams when i bought the stove and they sent someone to my house to measure. If i never bothered to download the pdf with the specs off of hearthstones web site I would have a stove that is unsafe in my house…

When you say you have 25" you mean from the hearth floor to the lintel, correct? A Homestead w/ just 4" legs is 25.5" tall. Only the rear portion will fit under your lintel. So, regardless of 4" or 6" legs you will have "the main body" of the stove flush with the hearth face at best. So, you need to consider the r-value you need in front of the glass door bearing in mind the stove will protrude from your hearth face at least 13". If you haven't printed the entire user manual PDF and the dimensions schematic, I'd do it now.
As for the guys at your stove shop, if they are like the guys at mine . . . they are well meaning and friendly, but they don't know my situation . and I've got some bad advice depending on who I talk to. (They are always CRAZY busy selling pellet stoves!). I've had to figure out a lot of this on my own. Figure out how far the stove will protrude from your hearth face. Then make sure you have 4" from the glass doors above the existing hearth, and an additional 12" beyond that must be r 2.5. Hope that helps. I'll probably be tiling this weekend and sending you questions on the hour! Good luck!

 

[Andy99]

Im going to extend the hearth. My wife wants something movable so I can put it away in the summer since its going to really stick out into the room. I think I will frame a box with metal studs enclose it with durock and fill it with Mineral wool insulation and then tile over the whole thing with granite that will match my hearth.
What do you think?

 

[badger1968]

Sounds bombproof Andy! :coolsmile: Have fun with it.

I'm about to start tiling my new hearth. Thanks for all your advice!

 

[Andy99]

Sounds bombproof Andy! :coolsmile: Have fun with it.

I'm about to start tiling my new hearth. Thanks for all your advice!

SO how did the tiling go???

 

[badger1968]

It was one of those things where you know if you had another chance to do it you could really do a good job. It's not fancy, but it is functional. The rather plain ceramic tile was my wife's choice. She likes the simplistic, rustic, " old-timey" aesthetic. Many times I thought to myself "patience!" When it was done, I second guessed the pattern. I wonder if I should have used whole tiles to the edge and used cut tiles next to the hearth face--rather than creating a "border" around the edges with cut tiles. I'll tile over the fairly ugly painted bricks when I can, and create a transition at floor level with oak carpet transitions.

When can I grout? Tomorrow? Again, thanks for your advice--it really helped.

 

[Andy99]

you can grout the next day with no problems. The pictures a little small but from what i can see it looks great.