hearth tile underlayment

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lmei007

Member
Nov 12, 2007
120
Boston MA
I finally removed the raised wood stove hearth and ready to make a new hearth which will be flat with the hardwood floor. But I found the hardwood floor is directly on top of the floor board and the floor board is directly on top of the joists. That means there is no room for cement board for the new hearth.

I have used the Schluter Ditra on my basement bathroom tiling. I don't know if it is good to use it here. Is there any special requirement about the material of the hearth underlayment?
 

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That is all determined by the stove you are planning to install.
 
Yup, need to know the stove's hearth requirements first. Or just let the hearth rise above the floor a bit. If in a traffic area it can have a beveled wood surrounding frame.
 
I don't know a stove that is able to installed on anything less than a regulation hearth pad which should be at least 4" masonry . I would lay brick or something down that is equal in thickness before putting stove on top . I know Olympia sells hearth pads for around 130$-$270 dollars depending on style throw that down
 
No way does any common stove require a 4 inch thick masonry under it. Many, if not most, require no more than ember protection. As Begreen said, read the manual for your stove. It will specify exactly what is required. Ceramic tile over a 1/4 inch Durock will give you that much and probably be close to the thickness of your flooring.
 
Once the R rating is established for the hearth you need to make the sub floor as solid as possible, another sheet of 5/8 plywood or cement board with not a million, but a zillion screws to keep it from flexing, if it isn't solid the floor could flex and the end result is cracked tiles / and cracked grout lines.
 
I don't know a stove that is able to installed on anything less than a regulation hearth pad which should be at least 4" masonry . I would lay brick or something down that is equal in thickness before putting stove on top . I know Olympia sells hearth pads for around 130$-$270 dollars depending on style throw that down
26 gauge sheet metal is approved for hearth protection on most new stoves, in fact it's mentioned as an example in most manuals. There are actually only a few being produced out there that still require R-value, if his stove does require R-value brick sure ain't gonna get it. It offers almost no R-value.
 
Common brick has an R value of .2 per inch. On the short 2 1/4" side that equals R=.45 and on edge it is R=.735. That's why it's approved for a 33% wall clearance reduction in NFPA 211.
 
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