Englander 30-NCH Hearth Pad

[Tio]

Long time lurker. Been trying to absorb as much information as I can. However, the time has come to come out of the bushes and make myself known.

My primary questions revolve around building the hearth pad. I am installing an Englander 30NCH wood burning stove. The required R Value is 1.5. My install location will be on the main level of the home that has a wood sub-floor (plywood on floor joists 16” on center). I see that a lot of people have used Micore in their pads. I am finding this very difficult to source. Yes, I can find it online, but I do not need 4 sheets of the stuff. So here are my plans/questions.

I am going to raise the hearth on some 2X4s. Should I use wood or metal studs? I have zero experience with metal studs. Does the “air space” created by metal studs count in the final R-Value calculation? I was then going to layer Durock on top of the 2X4s. The number of layers will depend of if the air space can or cannot be included in the R-value calculation. If not I think I need four ½” layers. The plan is to then tile the surface. What would be the maximum on center spacing needed to give adequate support for the Durock?

Thanks in advance for any advice and/or direction.

 

[begreen]

Welcome Tio. Yes, the air space has insulation value. If you put the metal studs on 12" centers they will support the Durock well. You could pop-rivet a sheet of 26 ga sheet metal to the top of the studs if you want to strengthen the support and add some heat radiation shielding. Then 2 layers (1") should suffice.

Here are a couple articles that should help out. The first article has an R-value table for various materials. The second has photos showing step by step construction. You can skip the metal lath if tiling.
https://www.hearth.com/econtent/index.php/articles/hearth_design
https://www.hearth.com/econtent/index.php/articles/stove_hearth_construction

 

[Tio]

Welcome Tio. Yes, the air space has insulation value. If you put the metal studs on 12" centers they will support the Durock well. You could pop-rivet a sheet of 26 ga sheet metal to the top of the studs if you want to strengthen the support and add some heat radiation shielding. Then 2 layers (1") should suffice.

Here are a couple articles that should help out. The first article has an R-value table for various materials. The second has photos showing step by step construction. You can skip the metal lath if tiling.
https://www.hearth.com/econtent/index.php/articles/hearth_design
https://www.hearth.com/econtent/index.php/articles/stove_hearth_construction

Thank you for the links. I had found the first one but not the second. It was very helpful.

What kind of R-Value can I expect from the air space created by using metal studs? In the table found in the first link there are multiple values for horizontal dead air space. Also the note about there being a debate about dead air space give one pause. I need to make sure I can demonstrate/document that I have met the manufactures specs for the insurance company. Of course they wanted it installed professionally. After speaking to them more they were "ok" with a DIY install as long as I can show that manufacture specs were met.

 

[begreen]

The horizontal dead air space is R=.97. Add two layers of Durock NexGen at R=.78/inch and you have well exceeded the mfg specs for the 30NC. Place the top layer of Durock at right angles to the bottom layer. Screw every 8". Note that metal studs come in different gauges. Get the heavier gauge studs.

Also, have you checked to see if there are any acoustic insulation companies in your area? Micore is used in cubical dividers as a sound proofing material. Another product that you could use with similar insulation value to Micore is called Fiberfrax. For Micore, call Building Specialties in Logan, UT to see if they stock or can order some for you. 435-792-4153

http://www.usg.com/where-to-buy.html#

 

[wit of a twit]

Hello guys,
I am also interested in the 30 nch to heat a draft 1500sqft home. However I have an existing fireplace in which I would like to install it. However the stove is too tall, and I was considering cutting down the legs by 3 inches to compensate, and fabricating legs. Furthermore the fireplace does not have the required clearance. I am assuming this clearance is for combustibles only. I will include an image of my fireplace in a later post, along with dimensions.

 

[BrotherBart]

There are six inch legs available on the Englander website. That is what I have on my 30 in the fireplace. A lot better than taking a chance on a busted leg dropping a 450 pound stove out into the living room with a fire in it.

Yes, it is just clearance to combustible material.

 

[Sprinter]

I'm curious. Do the shorter legs affect the required insulation value of the hearth?

 

[BrotherBart]

You would have to ask ESW, but I bet it doesn't. Back in 2005 when they started selling it that was the legs the thing had on it in the specs. In fact I bought it based on the published height and when I got it, it was three inches taller than the spec. Because they had changed to using 9 inch legs. So I have to think the UL test was done with the six inch ones. Or just on the ped.

 

[Sprinter]

That makes sense. This is sure to come up again.

 

[wit of a twit]

There are six inch legs available on the Englander website. That is what I have on my 30 in the fireplace. A lot better than taking a chance on a busted leg dropping a 450 pound stove out into the living room with a fire in it.

Yes, it is just clearance to combustible material.

View attachment 117364

That is the look I want! Though my other concern is regarding the rear blower. Does it get enough air flow? I have very little room for error w/ hieght. So, what is the total hieght of your 30 nch? did you paint your fireplace, as I was thinking about doing the same. If so, what did you use?

 

[blades]

Nix on paint, the 30 can get hot enough to bubble it right off, without over firing it unless you have it set using the clearances as a minimum number or add the side heat shields which are extra. rear heat shield is included. blower pushes air from floor up the back out over the top. but the variable speed/ on-off control is located right on the blower so for your installation you will need to get a bit creative in that deparment.

 

[stoveguy2esw]

You would have to ask ESW, but I bet it doesn't. Back in 2005 when they started selling it that was the legs the thing had on it in the specs. In fact I bought it based on the published height and when I got it, it was three inches taller than the spec. Because they had changed to using 9 inch legs. So I have to think the UL test was done with the six inch ones. Or just on the ped.

yes the stove was safety tested wearing 6 inchers,

 

[BrotherBart]

The fireplace interior is 1200 degree BBQ flat black.

 

[CenterTree]

The fireplace interior is 1200 degree BBQ flat black.

Just an FYI,,,, Rust-Oleum also makes a flat blk which boast 2000 degree protection,,,,for those who can never be TOO certain.
http://www.walmart.com/ip/Rust-Oleum-High-Heat-Flat-Spray-Paint-Black/17203457

I wonder if ya apply 2 coats,,,will ya get 4000 degree protection???

 

[BrotherBart]

I have never measured a temp over 235 degrees on the surface of those bricks in the fireplace with the stove running at full tilt. By the time they get to 1200 the stove will just be a puddle on the hearth.

 

[wit of a twit]

This is where I'd like to place my future nch.
Height of opening 26.5
Depth from rear to opening 24
Depth from rear to edge of fireplace 42
Opening width 34
Rear width 24.5
If the height of the nch is 26.75 with the 6 inch legs, i may still have to trim them. Then again, this may not be a problem as the front of the nch is shorter than the rear. I only wish i had my hands on one so I could properly measure it.