Thoughts on my "Controversial" install

[E Laszlo]

We recently built a house that was designed to accommodate my wood stove (woodstock fireview). This was not installed when the house was built, i am doing it now. Like many installations, clearance and space are issues - mine included. However, after years of research and planning, i believe my setup is fine... but there may be others that disagree and i'm open to suggestions and opinions. Really, I'm looking for reassurance! Here's what i have going -

1. Corner installation. As required by Woodstock, I have 12" clearance from the corners. Hearth pad is constructed per specs from Woodstock for the Fireview..

2. I'm running class A chimney straight from the stove (woodstock approved this) through a non structural and non combustible wall comprised of 20ga metal studs, hardibacker board (not durock because it breaks down at 200 degrees and max's at 10lbs sq/ft - whereas hardibacker maxes at 15lbs sq/ft with no heat limitations) and a limestone veneer. The stove connects behind the wall (yes i have access for clean out) to the main chimney and runs inside the house through an enclosed chase in the corner with proper 2" clearance (through my bedroom) and penetrates the roof near the highest point. Based on my research, this is textbook (except stove should be centrally located).

However, here's where my installation is controversial (although it shouldn't.. right?) - The non combustible wall (see terrible diagram below) is located a FEW INCHES from the rear heat shield. This is extremely close, but if a wall is non combustible it shouldn't matter, right? Also, I'll have a 1" air gap (top and bottom) for ventilation which should also act as additional heat shielding. (Hopefully?)

My biggest concern is the heat buildup in the corner and the non combustible wall. How hot will this wall get? Does it matter? Am I overlooking anything? Thoughts, opinions, reassurance ?

Thanks, Eric

 

[Jags]

Hmmm...interesting. Yes - non combustible is non combustible - but at some point does the non combustible wall connect up to one that IS combustible? Heat transfer would be my concern here.

 

[Highbeam]

It's not controversial at all. Ctc means clearance to combustibles period. You don't need any air gaps.

Is hardi noncombustible though. It looks like cardboard.

 

[Jags]

Is hardi noncombustible though. It looks like cardboard.

Hardiboard is different than Hardibacker. Hardibacker is a cement board similar to Durock.

 

[Chimney Smoke]

What is the non-combustible wall for? If you have your 12 inch corner clearances you don't need that back wall.

 

[rwhite]

I think your good. Hardibacker will conduct heat but is non combustible. Your air gaps should dissapate the heat. Sounds like an interesting install. I'd like to see some live pics of it.

 

[jetsam]

It's not controversial at all. Ctc means clearance to combustibles period. You don't need any air gaps.

Is hardi noncombustible though. It looks like cardboard.

It looks like paper-plywood dipped in cement, but it is almost all cement. JH has a stove install reference here. It is a lot more pleasant to work with than durock or wonderboard, but I am not sure which of the above is rated to higher temperatures. JH, for example, lists a jillion fire certifications, but no spec sheet with max allowable temperature.

 

[E Laszlo]

Great, thanks! This is the reassurance i was looking for. I became concerned when i got into a battle with a local fireplace store about the install. I was shocked by their ignorance, arrogance, and contempt for my install. He laughed at my Woodstock Fireview and said i shouldn't buy a no name stove. Not to start a debate, but in my opinion, Woodstock is the greatest company in this country! How could they not know Woodstock? I left and will never go back. Too bad, i wish i had a local wood store to go to.

Anyway, to answer a few questions - Yes, heat transfer is also a concern of mine. I hope the ventilated non combustible wall will dissipate enough heat.

The purpose of the wall is this - The WIFE! She wanted a fireplace with a mantel and I want a wood stove! I told her i could hide the chimney behind a wall and install a mantel. Yes, due to clearance issues, the mantel will be kinda high, but.whatever... it's there!

I have pictures of the install and will post very soon. Thanks, and stay tuned!

 

[E Laszlo]

It looks like paper-plywood dipped in cement, but it is almost all cement. JH has a stove install reference here. It is a lot more pleasant to work with than durock or wonderboard, but I am not sure which of the above is rated to higher temperatures. JH, for example, lists a jillion fire certifications, but no spec sheet with max allowable temperature.

Great link. It does say max temp of 100C... or 212F. That's not very high. When i spoke with them on the phone, they were quite vague and said not to worry. But 200 is not very high. Any idea How hot this wall could get? Any guesstimates?

 

[maple1]

I don't know how hot the back of a Woodstock Fireview gets - but I do know that radiant heat from a stove can make a wall very hot. That link also specs 100mm (4 inches) clearance to the stove - so as long as you meet that, I would think you're good?

How tight is the space behind it? Maybe you could add some discreet vents top & bottom to get air flowing behind the wall?

 

[bholler]

no problems i can see at all either the store was full of it if the wall is non combustible the stove could touch it with no issues. As long as you have your clearance to combustibles otherwise there is no issue.

 

[FTG-05]

We recently built a house that was designed to accommodate my wood stove (woodstock fireview). This was not installed when the house was built, i am doing it now. Like many installations, clearance and space are issues - mine included. However, after years of research and planning, i believe my setup is fine... but there may be others that disagree and i'm open to suggestions and opinions. Really, I'm looking for reassurance! Here's what i have going -

1. Corner installation. As required by Woodstock, I have 12" clearance from the corners. Hearth pad is constructed per specs from Woodstock for the Fireview..

2. I'm running class A chimney straight from the stove (woodstock approved this) through a non structural and non combustible wall comprised of 20ga metal studs, hardibacker board (not durock because it breaks down at 200 degrees and max's at 10lbs sq/ft - whereas hardibacker maxes at 15lbs sq/ft with no heat limitations) and a limestone veneer. The stove connects behind the wall (yes i have access for clean out) to the main chimney and runs inside the house through an enclosed chase in the corner with proper 2" clearance (through my bedroom) and penetrates the roof near the highest point. Based on my research, this is textbook (except stove should be centrally located).

However, here's where my installation is controversial (although it shouldn't.. right?) - The non combustible wall (see terrible diagram below) is located a FEW INCHES from the rear heat shield. This is extremely close, but if a wall is non combustible it shouldn't matter, right? Also, I'll have a 1" air gap (top and bottom) for ventilation which should also act as additional heat shielding. (Hopefully?)

View attachment 169688


My biggest concern is the heat buildup in the corner and the non combustible wall. How hot will this wall get? Does it matter? Am I overlooking anything? Thoughts, opinions, reassurance ?

Thanks, Eric

Where in the world did you get that information about Durock? It is noncombustible per ASTM E136 tests. See the data submittal sheet here: https://www.usg.com/content/usgcom/...nderlayment/durock-cement-board-next-gen.html

 

[maple1]

I don't think he said Durock was combustible.

 

[begreen]

I would also appreciate knowing the source of the breaking down at 200F, though there is no pressure load per se on a vertical wall. Also, which Durock product is that data for?

 

[begreen]

I'd also appreciate knowing the source of the breaking down at 200F, though there is no pressure load per se on a vertical wall. Also, which Durock product is that data for? I have not heard of any issues or failures with a proper Durock installation. Not a big fan of Hardibacker due to the cellulose filler in the product but I haven't heard of a failure with it either.

 

[E Laszlo]

I'd also appreciate knowing the source of the breaking down at 200F, though there is no pressure load per se on a vertical wall. Also, which Durock product is that data for? I have not heard of any issues or failures with a proper Durock installation. Not a big fan of Hardibacker due to the cellulose filler in the product but I haven't heard of a failure with it either.

I called usg direct and spoke with a technical specialist. They did not have "any products that met the needs of my installation". For me, the lack of strength (per sqft) is the real problem.

 

[skinanbones]

When you say that your going straight from the stove. Do you mean straight back into a tee and up? If so my only concern would be if the tee is certified for an interior installation. Some brands of chimney require special components when putting a tee inside a home

 

[pdxdave]

I personally wouldnt worry about that install. Common sense says you have plenty of clearance.

 

[burnbabyburn139]

You could also look into a product called skamotec 225.

 

[E Laszlo]

So here it is from the beginning. House was being framed and I stepped in acting like I knew what I was doing.

First, I dropped a plumb line (from the roof chimney chase) all the way down the interior of the house. Thankfully the chase was installed correct.

Now that I know where the chimney will be, I framed the hearth accordingly.

 

[E Laszlo]

Here's my framed hearth with my fireview stove template... Much easier to move this piece of drywall around then a 450lb pig! Now I just wait for drywall.

Drywall installed (by the worst drywall company ever. Don't ever cheap out on the drywall guy) Now that dropped in 30-35' of chimney, I noticed my outlet wouldn't line up... So I used a bottle jack out of my truck and lifted it! Worked perfect.



The chimney runs along the garage wall, Instead of a clean out access panel on my basement stair wall, I chose to do it in the garage.


Garage view



Not exactly roomy, but enough access to get the job done.

 

[E Laszlo]

So the real fun begins. The stone I'm using is fond du lac castle rock by Buechel stone.... 1500-1600lbs? I crated three templates for the hearth and walls that will be "stoned". After weeks and weeks of hammering, chiseling, cutting, grinding, swearing and drinking, the stone should be ready for installation.

 

[E Laszlo]

Back to the hearth and walls- starting with the hearth, I built it to woodstocks specs; sheet metal, 1/2" cement board and the stone.


20ga Metal studs with backer board.



Metal lathe. (Bloody hand not shown)



Scratch coat

 

[E Laszlo]

Well, placing dry stones on a template on the floor is really easy... Sticking these m f'ers to the wall is a whole new game. I have lots of experience tilting, bu not setting 25lb stones. The result... Crap results... So I tore em down!



After a few practice stones I found my rhythm (sp).



That's where I stand as of this last post. Hopefully, I can finish in the next week. We'll see.

 

[jatoxico]

Nice! Keep 'em coming!