Questions: Hearth base for Englander NC13

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stoichiometry

New Member
Oct 31, 2010
19
Near the ADKs, NY
Ok ... so I have some confusion about the manual for Englader NC13. There seems to be some discrepency here.

The manual states, "The type board you
choose should be U.L. rated and listed. After
examining the area you plan to place your stove
and determining it requires a board, the next step is
to select the proper size. The stove you choose will
determine the size board that is required. The
approved protector board should be large enough to provide a minimum of eight inches (8”) behind
the unit, eight inches (8”) on either side and sixteen inches (16”) in the front where the door is
located."

Most UL listed boards have an R-value of about 1.0 ... [a well made/respected brand advertises their one inch pads having an *impressive* 0.84 K value - this is just over an R=1.0]

And later in the manual, "If the appliance is to be installed on a combustible floor or a combustible floor covering, it must be
installed on a 1” thick non-combustible millboard floor protector or a durable equivalent, with a “R”
factor of no less than “2.”"

So ... I'm a bit confused [does it have to be a 1.0 or a 2.0]? More exactly, does my englander need to be on a hearth pad w/ a R=1.0 or should I build one with a R=2.0? The problem is that if I build one w/ R= 2.0, I think I'll need 5 inches of durorock (1/2 duro is advert as about R= 0.2) ... LOL.

THanks for any help.

-M
 
Hi

I have the 13 NCI and it needs R 2.00+ under the insert. I have the insert in the fireplace on the fire brick above the hearth. That is one of the problems with the Englander inserts as the r value for the bottom is very high. You will hear from others soon. I had to call Englander and get a clarification for my install they will answer your questions timely. Hope you don't have to have the 5 in. of durorock.
 
You can get commercial ceramic insulation sheets from refractory supply companies or maybe a refractory company in your locality. This what is used under the fancy hearth pads in the $400-700 range, It is not cheap but beats 5" of durorock. Also with the durorock , if you go that route, make sure you do not purchase the stuff with the Styrofoam beads in it. They due this to lighten the weight factor. I am lucky as we have to companies that repair and construct kilns here in town, so I was able to get the ceramic insulation boards through them.
 
For insulation board, ask for Micore, Rescor or Fiberfrax. One inch of this stuff and you are golden. Be sure to put a layer or two of cement board on top, screwed thru the insulation board for the tile or stone substrate. If no insulation board is available, you can also create an air space under the hearth using steel studs instead of wood to build the hearth.

If you can, use pure cement board like the original Wonderboard or Durock. FYI, USG states the beads in their NextGen product are not styrofoam, they are perlite. For sure you do want to avoid using their Permabase product.
 
I am having a hard time finding micore or rescore in northern new york. Seems most of the people up believe that one half-inch of durorock is 'more than sufficient' ....

it's frustrating ...

-M
 
Yes, this stove has tough hearth requirements. If insulation board really is not available, then make the hearth out of metal studs, pop rivet a sheet metal skin on top, then cover with a couple layers of cement board (rotate top sheet so seams don't align). Leave a 1" gap on front edge and at the back so that the air space can ventilate freely.
 
I came in here with the same exact question about the same exact stove. Definitely not something that I want to skimp on.

Anyone have any success finding Micore, Rescor or Fiberfrax? I live in a big city and still can't find any local distributors on the internet.
 
If you give tech support a call they should be able to send you a PDF document of a nice, tidy construction method for getting the R-value required.
 
I had the same question a few years ago. Had a difficult time finding micore etc.. I ended up using paperless drywall, topped with durock, then my granite tiles. Got it up to R2. 3 years, some raging hot fires in the stove, no problems whatsoever. The paperless drywall worked fine and is cheap and available at lowes.
 
My problem with using 2X4s to create an air space is that they are a combustible surface.

Also, using metal studs doesn't seem like a good solution because metal easily conducts heat.
 
alleghenyman said:
My problem with using 2X4s to create an air space is that they are a combustible surface.

The 2x4's are just around the sides and front. To support the middle I made a couple of piers out of drywall with the paper removed. I have the over minimum 8'' on the side and the 16" in the front clearances.
 
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