R-value insulation..HELP!

[Andy99]

The hearth I sat my stove on meets the 2.5 required r-value but does not come out far enough into the room.
I'm building a addition to the hearth that will be in front of the stove not under it. The Stove manual says I need an r-value of 2.5 for this part also. Now I have metal studs to frame out a box about 18x36 that needs to be placed in front of the hearth the stove is sitting on. Im using a backer board to enclose the box and Then im going to tile the top and sides to match my hearth. Now what do I need to fill the box with to get to the 2.5 r value. I was thinking rock wool? but I cant find it at Lowes or Home depot unless Im looking in the wrong spot. Can I use regular Pink panther type Insulation Since it says it has an r value of 13???

 

[Andy99]

I just thought of something else.

I was going to use Durock but its heavy and a pain to cut. Can I use a fiber board instead like hardy board?
Will this meet the heat requirement?

 

[Andy99]

Im giving this a bump I would like to get an answer soon since I wanted to start this project in the morning and was planning on trying to buy the supplies after dinner tonight.

 

[Vic99]

Hey Andy,

You must have the homestead with the 6 inch legs and the bottom heatshield (like me) for the R 2.5.

I was going to do something silmilar to what you are doing with slate, but I ended up buying a premade hearth pad and put it right over my original fireplace hearth (which was too small).

This chart will help you get to R 2.5. I love this guy's site and would use his shop if I lived in WA state.
(broken link removed to http://www.chimneysweeponline.com/horvalue.htm)

Don't use fiberglass insulation . . . when I researched this, I was told that it's considered combustible for the stove's temp. I note that rockwool is not listed on the chart.

Good luck, the homestead is a nice medium sized stove . . . I'm currently burning what's left of last year's pallets in it now.

 

[Highbeam]

Read your stove's manual. There is a section in there with a table that applies perfectly to your situation. You could do like I did and fill the space between those studs with ... air. Air is a great insulator.

 

[webbie]

Right - air might be the perfect insulator in this case. Maybe suspend a piece of sheet metal 1/2 way up between the studs (like a pan)....that will give you two air spaces plus the 2 or so layers of cement board on top (usually needed to make it strong)....that would do the job,.

 

[Andy99]

I might have to go with air. I cant find Mineral wool anywhere and Ceramic fiber board is also almost impossible to find locally. I dont know where else to try. I have one last place I want to call in the morning. Its a masonry Yard that sells fireplace supplies.

 

[begreen]

By all means use a pure cement board like Wonderboard or Durock. It's not that bad to cut. Just score it deeply with a utility knife on both sides, then snap it at the score line. It will break cleanly.

 

[webbie]

In our area, sheet rock (drywall) supply houses sell various types of rock and mineral wool. But, then again, air and sheet metal are cheap.

 

[Andy99]

I found Mineral wool

If anyone on Long Island is looking for it. Riverhead Building Supply has it. and it was only 30 bucks

Now I have everything I need. Wed Night is the Night I get to work on it!