Iron under hearth

[mattmania]

So I have a Englander stove...I made a platform out of it with some stacked cement board. Just wondering what the pluses and minuses of finishing the hearth with ceramic tiles versus iron/steel sheeting (say 0.20 inches thick or so). I like the aesthetic of black painted metal (satin), but I am just wondering if it has worse insulating properties than ceramic tiles...or whether it would be dangerous in general. The stove does have legs on it.

Any thoughts?

 

[D9H]

steel plate transmits heat much more than ceramic tile.
Cement board is not very combustible so...
you're (prolly) not gonna catch fire, but...

ceramic tile would be better

 

[begreen]

Tile has little insulation value. As long as the proper insulation value of the hearth is reached an iron cover should be ok. What brand and type of cement board was used and what Englander stove is this and how many layers?

 

[mattmania]

Tile has little insulation value. As long as the proper insulation value of the hearth is reached an iron cover should be ok. What brand and type of cement board was used and what Englander stove is this and how many layers?

I used a layer of cement board (Duraboard, next generation, and then over an inch of a cement/fireclay/perlite mixture, fiberglass reinforced (little strands of fiberglass in there). I figure I have over R2 with this configuration alone. I am just wondering if the iron will raise this R value, keep it the same, or lower it (only the latter being a problem).

 

[begreen]

I take it that this for the 13NC. Duraboard is not cement board. Did you mean Durock NexGen? What formula was used to come up with the R value estimate for the perlite cement mix?

 

[mattmania]

I take it that this for the 13NC. Duraboard is not cement board. Did you mean Durock NexGen? What formula was used to come up with the R value estimate for the perlite cement mix?

It is for the 13, yeah. It is Durock 2nd generation. The formula was about 15 percent perlite, 15 percent fireclay, 50 percent silika sand (super fine, clay like), and then 20 percent cement.

 

[begreen]

Interesting, hope you are taking pictures. What was the R value calculation for the perlite cement mix?

 

[mattmania]

Interesting, hope you are taking pictures. What was the R value calculation for the perlite cement mix?

Hmmm...well I actually didn't do a calculation...just a hinch I am working off of. I actually did a test run with a 3/4 inch piece, and heated it up with an electric coil stove on high. It did a surprisingly good job. One side was as heck, and the other just warn. How would I calculate R value?

 

[begreen]

LOL, that was my question.

 

[notshubby]

LOL, that was my question.

heres a short list of r values on some materials. I cant find the link I had to a much longer list. steel has virtually no r value so it wont be listed anywhere. but it is a noncombustible covering or radiant heat shield if installed with air gap behind or below it. btw the next gen durock is good for .39 per half inch. remember a 1" ventilated air gap is good for 1.43 and is probably higher r value than your perlite cement fireclay mix. key word ventilated the 1" air gap without airflow is .9 if I recall correctly. your steel will not raise or lower your r value.


(broken link removed to http://chimneysweeponline.com/horvalue.htm)

ohh yeah tiles r value is like .02 for each 1/4 inch not enough to say so.

 

[notshubby]

heres a short list of r values on some materials. I cant find the link I had to a much longer list. steel has virtually no r value so it wont be listed anywhere. but it is a noncombustible covering or radiant heat shield if installed with air gap behind or below it. btw the next gen durock is good for .39 per half inch. remember a 1" ventilated air gap is good for 1.43 and is probably higher r value than your perlite cement fireclay mix. key word ventilated the 1" air gap without airflow is .9 if I recall correctly. your steel will not raise or lower your r value.


(broken link removed to http://chimneysweeponline.com/horvalue.htm)

and I would think that calculating the r value of a mixture would require testing and be more complex than just averaging out the r values of all ingredients. your average building inspector might not know any better but I'm sure any wett inspector would fail an unknown mixture. my inspector looked up the required value and I showed him construction pics of every step and layer and rattled off the r values which added up to about 3 times the required which made him very happy but I also had the feeling he was clueless and I could have made up numbers and he wouldn't have known any better.