Pleasant Hearth clearances.

[Koda6966]

I am doing a corner install on a Pleasant Hearth LWS-127201-B that the manual says to maintain a 12" distance from combustibles for the back wall. If I install with a 1" air gap and 1/2" durarock/tile, will I still need to follow this guideline or would that be considered a non-combustible wall and I could reduce it? I plan on doing it with either hat channel (if I can source it) or step it up a little and use metal studs on their sides.

For the hearth, I plan on building it with wood 2x4's for frame work, with plywood and then two sheets of 1/2" micore, followed by durarock and tile. The micore on its own should get me above the 2.0R rating the stove manufacturer calls out.

 

[bholler]

No you usually cant reduce below the 12". But check the manual it should tell you

 

[Koda6966]

Found a tidbit in the manual that says if I install a non combustible covering on the wall I can go to the manufacturer of whatever wall covering's guideline. Durock says I can use a 2/3 reduction. Idk if I'd go that far but it should allow me to move it back far enough to keep a 5x5 hearth. Insurance company says OK.

 

[begreen]

Found a tidbit in the manual that says if I install a non combustible covering on the wall I can go to the manufacturer of whatever wall covering's guideline.

The stove docs are misleading with this statement. The text from Durock sounds like it is out of context. Durock can be used to make a ventilated, NFPA 211 wall shield that will provide a 66% clearance reduction - from 36" to 12". The stove docs are correct that you may be able to get a variance from your local building inspector. If that person is willing to sign off on the reduced clearance in writing, then it should be ok.

Note that you can also achieve your hearth requirements with one 1/2" sheet of micore and then 2 sheets of Durock NexGen. That would be a stiffer base for the tile.

 

[Koda6966]

I found the expanded document from Durock that had the information I was reading. The short bit that I found on another post left out that the minimum is 12."

What I read - "Used as a wall shield DUROCK cement board reduces by two-thirds the manufacturer specified clearance between the room heater or stove and a combustible wall surface."

What USG's actual document says - "The reduced clearances (minimum 12) with a wall shield of Durock cement board are shown below. Check the graph for the exact reduction you can make in the manufacturer’s specified clearances and calculate the floor space you can reclaim." blahblah

I'll be safe stick with the 12" distance. It's just surprising that the stove manufacturer would use the minimum clearance to a combustible with a wall shield as their minimum clearance to combustibles.

 

[bholler]

I found the expanded document from Durock that had the information I was reading. The short bit that I found on another post left out that the minimum is 12."

What I read - "Used as a wall shield DUROCK cement board reduces by two-thirds the manufacturer specified clearance between the room heater or stove and a combustible wall surface."

What USG's actual document says - "The reduced clearances (minimum 12) with a wall shield of Durock cement board are shown below. Check the graph for the exact reduction you can make in the manufacturer’s specified clearances and calculate the floor space you can reclaim." blahblah

I'll be safe stick with the 12" distance. It's just surprising that the stove manufacturer would use the minimum clearance to a combustible with a wall shield as their minimum clearance to combustibles.

That is because they already have a radiation sheild on the stove. Doubling them does not help much

 

[Koda6966]

All of this is new to me. I lived my entire life with a woodstove that just sat on an inch and a half slab of bluestone.

 

[Koda6966]

So in other words, building a ventilated wall shield is redudant in this situation.

 

[bholler]

So in other words, building a ventilated wall shield is redudant in this situation.

Yes exactly