R Value For Hearth Pad Under a Oslo F 500

My manual does not specify r-value. I can tell you the brick under mine gets pretty dang hot at times. We put down 4 layers of half inch durock and brick on top. I think that, with mortar, gave us around r=1.7. We did this to give us the r value required of the alcove installation just to be safe. Also, it will allow us a decent selection of other stoves in the future should we wish to change what we have, without ripping up the hearth.

kork said:

I can't seem to find it in the manual. Only listed for alcove install at 1.6. Anybody? Would appreciate any info .

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There is no specified R value requirement . . . only requirement is for "ember protection" according to my dealer.

I had the very same question when I was building my hearth . . . dealer said technically I could get away with sheet metal under the stove, but a) being in my profession I wanted to have a bit more protection and b) I knew my wife wouldn't be so keen on having a large slab of sheet metal in the living room.

So . . . in summation . . . pretty much any non-combustible floor protection will work . . . that said, in Bangor our Fire Inspector (the Authority Having Jurisdiction) requires some proof of listed floor protection so simple ember protection isn't enough in this City.

You can do a search to find out more details about my hearth, but basically I used two sheets of plywood (for rigidity) with a 1/2 inch sheet of Durock screwed and mortared to the boards with slate tile on top. It doesn't offer a lot of R value, but it does go above and beyond what is required by Jotul and meets the Code (and most Inspector's) requirements . . . plus I sleep well at night.

If you do build (or buy for that matter) your hearth I would strongly encourage building/buying larger than you need . . . having more of a hearth is nice for those little moments -- such as "Oops, I just spilled a bunch of embers out on the hearth and I'm really glad I have a larger hearth so they didn't end up on my hardwood floor" or "Oops, I just spilled a whole bunch of messy ashes on the hearth, but it's not a big deal since I can easily sweep them up" . . . plus the larger hearth will give you a place to sit stuff on next to the fire (i.e. your tools) and yourself for that matter . . . and as a final plus . . . your cats/dogs will appreciate the new "bed."

#1, there is no requirement

#2, my Oslo gets VERY hot underneath =- so much so that I am surprised that there is no requirement!

#3, I have 1 sheet of 1/2" plywood, 1 layer of cement board, and then ceramic tile.

The tile gets HOT. I am thinking of installing the bottom heat shield next year... it seems too hot too me...

The Dali Lima said:

#1, there is no requirement

#2, my Oslo gets VERY hot underneath =- so much so that I am surprised that there is no requirement!

#3, I have 1 sheet of 1/2" plywood, 1 layer of cement board, and then ceramic tile.

The tile gets HOT. I am thinking of installing the bottom heat shield next year... it seems too hot too me...

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Place an upside down cookie sheet on the floor under the stove, this should drastically reduce the temps of the flooring underneath it.

The Dali Lima said:

#1, there is no requirement

#2, my Oslo gets VERY hot underneath =- so much so that I am surprised that there is no requirement!

#3, I have 1 sheet of 1/2" plywood, 1 layer of cement board, and then ceramic tile.

The tile gets HOT. I am thinking of installing the bottom heat shield next year... it seems too hot too me...

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Did your Oslo come with a bottom heat shield? I thought that was standard for the Oslo . . . I put mine on and can tell you that it really isn't all that hot underneath . . . warm . . . but pleasantly warm, not hot.

Really... Are you using the normal height legs and heat shield that is supplied with the stove??

They installed my bottom heat shield and with the stove at 600 degrees my concrete hearth stays surprisingly cool. I do keep the ashpan full at all times though, so maybe that makes a difference... 8

With the stove running at 500F, the warmest place seems to be the four sq. ft. right in front of the glass. While it is hot, I'm able to stand on the tile bare foot.

Jim

Thanks for the responses! The stove has an optional bottom heat-shield. The floor gets pretty hot underneath and while it is no issue right now, I don't like the prospect of 15 years of intense heat on it so I may opt for the shield in the summer.

jbrown56 said:

With the stove running at 500F, the warmest place seems to be the four sq. ft. right in front of the glass. While it is hot, I'm able to stand on the tile bare foot.

Jim

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Same here . . . when it's wicked cold outside and I've just come inside standing (or sitting) right in front of the window is the place to be!

The Dali Lima said:

Thanks for the responses! The stove has an optional bottom heat-shield. The floor gets pretty hot underneath and while it is no issue right now, I don't like the prospect of 15 years of intense heat on it so I may opt for the shield in the summer.

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I suspect you would see a pretty significant change in temp with the heat shield installed.