Newbie hearth question

[overjr90]

Hi everyone,

I'm going to be getting an Osburn 2000 wood stove installed this fall, and I'm trying to build a hearth pad for it. The contractor doing the install said it had to be 2 inches thick, not sure about specific r/k values. I also can't find anything in the Osburn manual that explicitly gives these numbers for the stove. Why would they hide this number? Does anyone know how to find this info for Osburn 2000?

Either way, my basic plan is to get a 1/2 in base of plywood (any particular kind?), then layer 1-3 1/2 in wonderboards with thinset in between each layer, then lay tile on top of the wonderboards. Do I need to use refractory mortar for the tiles? I'm obviously not great with terminology and I'm a computer guy by trade, so if anyone has any tips let me know.

 

[Grisu]

I took a look at the manual and it seems you need only an ember protection without having a specific r-value. It is my understanding that the 2 inch raised floor protection is required only for mobile homes. Hence, you may need to do much less work. I would call SBI (the Osburn manufacturer) for a definitive answer.

 

[Darl Bundren]

One thing you might consider is to raise the stove higher than the two inches. I built a hearth for my stove out of 2x6s, 3/4" plywood, and wonderboard and tiled it, and it raised the stove about six inches off the floor. Less stooping and easier loading. Good luck with the install.

 

[Jags]

Ember protection means just that. A non-combustible pad. Unless you live in a mobile home, the thickness is a moot point (and personal preference) assuming that you meet the non-combustible requirement.

 

[overjr90]

Thanks for your replies guys. I asked the manufacturer and they said the following: "We do not mention a specific R or K value because the floor protection does not need insulation on this particular model. It only needs to be made of non-combustible material (steel, ceramic, brick, hardy board, etc.). The 2” thickness is only required if you install the unit on legs in a mobile home. Is see you will order your stove with a pedestal, so you do not need that 2-inch thickness."

So I think my plan will still be to build a nice hearth pad and use wonderboard/durock just to be safe. I'm thinking of putting some 2x2s spaced along the bottom, then a layer of 1in plywood, then the backerboard, then the tile. It will be framed with 2x4s. Sound good?

 

[begreen]

Sounds fine. Screw down the cement board per directions. Use latex modified thinset to set the tiles (no adhesives). Take some shots as you progress.

 

[overjr90]

this may be more of a general question. i'm just wondering how i can get some cheap 2x2s. All I'm seeing are 2x2x8s for over $5 a piece at HD/lowes. at that rate it would cost at least $125 just to put 2x2s 1 foot apart across the bottom of the pad.

can i use deck deck balusters for this? should i just forgo the lower layer and just do the plywood/durock/tile layers?

 

[begreen]

That sounds much too high, they should be under $2. Are you sure they weren't finishing wood of cedar or hardwood? How big is this hearth going to be? $125/5 = 25 sticks. That's enough to make a 25' x 8' hearth! If you can't find 2x2s, just use 2x4's laid flat instead of on edge. If you are using 1" plywood, 16" on center is plenty.

 

[overjr90]

i think i will do that and just get 2x4s to lay flat 1 ft apart on the bottom....

 

[ScotO]

Make sure your local codes don't contradict the manufacturers install recommendations......maybe that's what the installer is referencing. Either way, consider doing a raised Hearth. Much easier to load the stove that way. I wish I had done a raised Hearth in my Napoleon 1900p install back when I built it several years ago, especially as I get older, it'd be alot easier on the back down the road.......I may redo that hearth a couple years from now.

 

[overjr90]

question for this helpful forum

i have most of the materials besides the "latex thinset mortar". the people in lowes had no idea what that was, but i see the following available at HD, that's what i want right? i would like to have some leftover as i will be doing a bit of tile by the front door as well (75 sq ft)

http://www.homedepot.com/p/Custom-B...Thin-Set-Mortar-MTSW50/100091767#.UgkN62SFTF8

so i have my layer of 2x4s, laid flat on the ground, 8 in apart. then i will have 1/2 in plywood. next i will put the cement board. i am just wondering if i will need to use some sort of mortar (the type above?) on top of the plywood and underneath the cement board layer, or if i can just screw the cement board into the plywood board. thanks everyone!

 

[overjr90]

anyone? thanks again!

 

[overjr90]

bueller?

 

[aansorge]

Just screw the durock to the plywood and use the thinset mortar to apply the tile.

 

[begreen]

Use 3/4" plywood to reduce flexing. 1/2" ply is too thin. 2x4s laid flat can be on 12" centers. No need for mortar between the cement board and plywood. Yes that thinset will work, but no need for white. Screw down the cement board with a screw every 8" using the proper screws for cement board.