Raised hearth on concrete floor in split-level home...have some questions

[Z71Edge]

Hi everybody, I'm new the the forum and I have a few questions. I've been doing some research on added a wood stove of my split level home, mostly to use a secondary heat source to offset the propane bill.

My biggest question is regaurding the construction of my corner area raised hearth. I plan to run an Englander NC13, as my total house size is 1800 sq. ft. and I primarily just want to run the wood stove while down in the "mancave" watching TV and to offset the propane bill...down the road, I may possibly consider an NC30 or something similar, however right now, I think the NC13 will be plenty for me & the family. So, all that considered, I want to build the hearth to accomidate either one from the start.

Biggest confusing road block I have comes down to proper insulating the area for the R2.0 required by the NC13. Since my flooring underneath the metal framework is already concrete & noncombustable, is it necessary to make sure I am exactly R2.0? Or can I frame this area in like the link below and do this exact setup (3.5" airspace, 2 sheets Hardieboard, plus stonework)? I keep reading about people using Micore300 & such items, but usually this is because they have a wood floor underneath...mine is concrete. I could save a ton of money (as most of you know) by not using this Micore300 material if I don't really need it.

I want to build the my hearth to pretty much look exactly like this one ( https://www.hearth.com/econtent/index.php/articles/stove_hearth_construction ), except I am going to continue the stone work up to the ceiling and the pipe will be going out the sidewall of my house. The stove will be in the lower "sub" level of the split level, not in the basement. Since I am going to be going out of the sidewall, do I have to frame in some sort of a "firebox" inside the wall (along with running the proper duct work/cleanout of course)?

There's a lot of info in my first post, but I have a lot going through my mind with this setup, as I'm sure you all did too when you were at this stage of the game. Anybody with this setup or that has any tips of me would be greatly appreciated. I can post pictures if needed. Thanks!

 

[SteveKG]

Since your floor is noncombustible, are you wanting a hearth just for looks?

 

[Z71Edge]

Yes, mainly for looks...yet there is some function to it, being the rest of the room will be in carpet, I feel it will be a little safer having the stove slightly higher than the carpet...but maybe this doesn't make a difference?

 

[aansorge]

You could simply lay tile right on the concrete if you want. No need to raise it up unless that is the look you want.

 

[bholler]

there is no real functional gain of a raised hearth but if you like the look what i would do is just build it out of concrete block and then backer board and tile. As far as the walls go if you want to reduce the clearances you will need an air space if not you can just put backer on the wall and stone over it. I dont know what you are referring to as ducting do you mean your chimney? If so you will need to gat a wall pass through and frame the hole according to those instructions. Some pictures and a more detailed description of your proposed chimney setup will help us give you better info.

 

[begreen]

You can frame like the linked article shows as long as the carpet is removed in the hearth area first. Both these stoves have a shortish pedestal. If you want to raise it higher maybe use concrete blocks to bring it up 8"? Mortar in place and skin with Durock, then tile? Or just build up a couple courses of brick?

Also pay attention to the side and rear clearances. If doesn't hurt to build a bit large so that you have some extra wiggle room. What is the wall construction behind the stove where the thimble goes through the wall?

 

[Z71Edge]

Alright guys, sorry if anything I said was confusing...I attached a couple pictures. One shows the corner where I plan to put the stove...the other two pictures are proposed layouts of the hearth that I sketched up (basic 5ftx5ft square with the front corner trimmed off)...one shows with an NC13 dimensions and the other with the NC30.

Just like you said, I'm trying to give myself enough wiggle room incase I want to run an NC30 down the road. At the recommended 18" from ceiling, the wall construction where the thimble will be is just a plain exterior framed in wall that is on top of the concrete block wall of the sub level...there is no chimney built into the house.

For the floor, If I will be perfectly fine building up a block base and skin it with the Hardieboard, then thats what I will probably do. I was just unsure if there was any added benefit to framing it in like the above link. Also, since I do NOT have a chimney setup, I was unsure if it would be best and safer for me to frame in the wall and skin accordingly, rather than just skin over top the drywall and call it good...I would think the framed in setup would be safer for this area of the thimble and duct work to run through? But maybe I am wrong...

Hopefully this makes a little more sense and gives everybody a good idea of what I have to work with and wanna do.

 

[bholler]

Well before you do any framing for the thimble you need to decide what chimney you are going to be using and at least get the wall pass thru kit so you can frame accordingly. But it would be best to get the whole chimney system so you have it there and can read and follow all of the instructions. As far as the walls go if you are not trying to reduce clearances you can put backer directly to the studs over the drywall or whatever you choose. But you really need to figure where and how you are venting the stove before you go any farther that is way more important than the cosmetics and could possibly change your plans.

 

[Z71Edge]

Well before you do any framing for the thimble you need to decide what chimney you are going to be using and at least get the wall pass thru kit so you can frame accordingly. But it would be best to get the whole chimney system so you have it there and can read and follow all of the instructions. As far as the walls go if you are not trying to reduce clearances you can put backer directly to the studs over the drywall or whatever you choose. But you really need to figure where and how you are venting the stove before you go any farther that is way more important than the cosmetics and could possibly change your plans.

Are you talking about how I want to run the chimney stack outside? In that case, I will be coming out of the stove to a 90 and out the sidewall (yellow unpainted area in pic), 18" down from ceiling to top of pipe. I will then continue the pipe outside and up off side of the house, up to appropriate height above roof. That's the plan I had anyway. So, I basically need to get a wall pass thru kit and thimble so that I can frame all this in...this is where I started considering if I need to frame the wall out or not before I get ready to put down the backerboard.

 

[begreen]

You will need to box frame the wall kit for the thimble between the appropriate studs. Here is what the DuraTech kit contains. They have good instructions here under the literature tab:
http://www.duravent.com/Product.aspx?hProduct=1

 

[Dix]

We raised it a touch.

Thinking on it now, I'd be "why bother".

Mine is also on a slab.

Welcome to the forums !

 

[Z71Edge]

Thanks guys! I will check to see if my local Home Depot has any of those kits In-Stock yet

One last question...reguarding the setup I plan to run, is it necessary for me to hook up an outside airline to the duct on the back of this stove? The manual states that this is only "required" if you have a mobile home, but recommended for normal home. So what have most of you done?

The room is fairly large where it will be, so I would think It can pull enough fresh air from within the room without having the outside hookup...however, if I will benefit at all from it, I can run a line while I have the wall torn up when doing the through wall kit.

 

[begreen]

The need for outside air may depend on whether this is a negative pressure zone or not. Basement installs can have this problem especially if there are competing devices like clothes dryer, gas hw heater, gas furnace, bathroom fan, etc.. You could try it without, but it might be good to go ahead and install if there is potential for this issue.

If the sill is leaky then air may make it in and the stove will work ok, but in that case I would seal up the sill and insulate the joist space for better heating.