# Combustible ----> Non-Combustible Wall



## DangerMouse (Jul 17, 2008)

ok, i'll bite.... why?

DM


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## Sammy (Mar 11, 2007)

Brick...


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## Termite (Apr 13, 2008)

Yeah, I'm going to have to ask why as well. Is the intent of the noncombustible wall to separate two adjoining residential spaces (duplex, etc) or separate occupancies of another sort (house from a business)? 

I'm well versed in firewalls and fire separation assemblies but need to know exactly what you're doing. The question is just way too vague.


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## bjbatlanta (Jul 16, 2008)

KC, is plaster considered combustible or does it not have a fire rating?? Just for my own edification....


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## DangerMouse (Jul 17, 2008)

i didn't think plaster burned neither. i wondered the same thing.

DM


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## nap (Dec 4, 2007)

bjbatlanta said:


> KC, is plaster considered combustible or does it not have a fire rating?? Just for my own edification....


 
there is a difference between a wall being fire rated and totally non-combustable. A fire wall is not neccessarily completely non-combustable. It is merely rated to restrict fire travel for a specified period of time.

OP needs to clarify what he needs and why.


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## bjbatlanta (Jul 16, 2008)

Very true, nap. Even the face paper on the drywall and the tape on the joints is "combustible". And cart1081 did specify "completely non-combustible". Sammy may be on the right track......fire brick??


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## DangerMouse (Jul 17, 2008)

yeah, he could just put up steel barn siding.... that's pretty well firePROOF... need more input

DM


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## Termite (Apr 13, 2008)

I wouldn't think that plaster has any combustible properties to it...
But you don't see much plaster in rated walls in these parts either. A fire protection engineer could certainly specify plaster when determining a wall assembly's fire rating, although I've never seen it done, and am unaware of any UL or GA fire rated assemblies that incorporate it. 

NAP is correct, noncombustibility is not usually an issue in residential (type 5) construction, the assembly of wall board, insulation, and framing in a certain way lends itself to resisting passage of fire and protection of structural elements. 

Sheetrock is fire resistant, but the paper face is in fact combustible. Sheetrock's ability to withstand heat and fire comes only from the moisture content of the gypsum core. When the moisture is cooked out of it, the panel fails.


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## bjbatlanta (Jul 16, 2008)

Thanks KC. It was my own curiosity that sparked the question. Common sense says plaster would be a "fire resistive" substance. Since it is not commonly seen/used, I was interested to see if you were aware if it had any "rating". Didn't mean to get the thread off track. Understand that it's probably not a "cut and dried" answer, and here the key word was "non-combustible" not fire rated. Looking forward to more info from cart0181 to see how this plays out. The fire marshal always holds the "trump" card when it comes to getting a C.O., so it's nice to have as much knowledge of ratings/codes as possible to keep up.


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## Termite (Apr 13, 2008)

I'd say that plaster would definately be noncombustible. Remember that materials themselves don't really have a "rating". In order to get a rating you've got to combine materials. What I mean is that sheetrock or plaster alone are pretty worthless in a fire without other means of support (studs, joists, etc), creating an assembly.

There is a big misconception out there that sheetrock has an hourly rating...Like 5/8" type X gypsum is 1 hour. Not true. To get the one hour rating, the rock has to be fastened a certain way with certain screws or nails to certain framing members at a certain spacing. Fire is laid to the assembly for an hour, and then the assembly is hit with a firehose stream. Even if the assembly survives the fire, it may fail due to the hose stream portion of the test. Every UL and GA assembly you see have passed that test.


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## DangerMouse (Jul 17, 2008)

well, this guy could be a 'fire artist' that uses a flame-thrower to do his art, for all we know! until he comes back to tell us why, all we can do is speculate! but it's interesting anyways....

DM


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## cart0181 (Oct 26, 2008)

Wow! Okay, I've definitely found the right forum here! Thanks everyone so far for your responses. I apologize for not checking back on this sooner. I didn't expect such a great response.

The application I'm talking about here is for a wood-burning stove. Unfortunately, I haven't been able to identify the manufacturer of the stove because I got it "as is" and I believe it is very old, maybe even antique. If I knew the manufacturer, I could follow their guidelines if they had it UL listed, but that option seems out at this point. That being said, I can follow the "Standard" clearances set forth by the NFPA section 211. http://www.nfpa.org/freecodes/free_access_document.asp?id=21103 These codes require a clearance of 3 feet in all directions from *ANY* combustible material (yes, the lath boards qualify, as do the wood studs they're mounted to) unless you use some sort of "clearance reduction system," which reduces the clearance to 1 foot. The clearance reduction system is basically a non-combustible wallboard such as Durock spaced out 1 inch from the combustible wall using non-combustible spacers of some sort. That would be no problem, but unfortunately, 1 foot isn't quite close enough for me.

So the problem remains. How can I get closer than 1 foot? *It seems to me* the only way to do it is to *eliminate all* *wood* from this wall by re-building it entirely with non-combustibles. As I already said, I do _want_ the wall where it is and I believe it to be *load bearing*. Unless someone else here can think of another sneaky way to do it?

I'll post some pics also to make it more clear what's going on.


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## cart0181 (Oct 26, 2008)

Here's the pictures, just click the thumbnail for a larger size.









The stove is positioned exactly 1 foot from the combustible walls in the pictures. Unfortunately, it's not where I want it to be. I need it a little closer so it will be out of the walking path. There will also be a pad which must extend 18" from the front loading door which would put it half way into the hallway. Totally unacceptable!


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## DangerMouse (Jul 17, 2008)

it's POSSIBLE a half-brick wall could be put behind that cute lil' thing! but full brick may be necessary, or worse..... even 2 or 3 inches from the brick, it'll still be in the way, and if it gets too hot on the outside.... no-where else you can hit the chimney? the other side is probably not an option as you'd have to turn it around and that design probably isn't on both sides, or is it? can you put it perp to the wall? too much in the way there? our woodstove is only 6 inches from the wall, but it's floor to ceiling brick for the whole wall. chimney hidden between 2 closets in the master bedroom.

DM


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## bjbatlanta (Jul 16, 2008)

3 feet in ALL directions? What are you going to do with the floor?? You can rebuild the wall out of metal studs (you can get load bearing at a drywall supply) and hang your durock..... There's probably a better way though. I'm sure there will be more responses.


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## DangerMouse (Jul 17, 2008)

if that thing radiates heat, that back wall will need to be able to take the punch. and there is no way i can see that you'll fit an 18" apron in front of the loading door, even if you had it 2 or 3 inches from the chimney. is that chimney drywalled over? painted brick? can't tell from the size pics. it'll need to be able to take the heat too. maybe if the archway is large enough, you could make it a bit smaller to make the wall longer? 

DM


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## cart0181 (Oct 26, 2008)

@bjbatlanta - The floor will be to code once I put in the hearth pad, that's not a problem. I'm just hazy as to _how_ to go about rebuilding the wall. You say I can get load bearing metal studs. Okay, I'll look for those. Would they have those at a standard home-improvement center? Also, how would I support the structure while I remove the wooden studs? Do I have to use a jack or something? Or is that unnecessary?

@MdangermouseM - The castings do appear on both sides of the stove, but the other side of the wall is inside a closet, so I can't put it on that side of the chimney. As for the "left" side of the chimney, it would require me to re-route my gas furnace's return air duct down in the basement. As for "in front" of the chimney, the stove would be way out in the center of the room. As for perpendicular to the wall as you suggested, that might actually work. I'll have to look at that more carefully. I worry about slowing down the "draft" in the chimney, though, and I was really hoping to go straight in (perpendicular would require a 90 degree elbow in the stove pipe followed immediately by a 90 degree tee up into the chimney). Trust me, I'm pretty sure this is where I want it and it's _almost_ there. I think if I can get it about 6 inches closer it will be great. I'm not worried if the pad extends _part way_ into the hallway, but just not the full 18 inches. I have a plan for a very "low profile" hearth pad so people won't stub their toes on it as they walk past. I like your idea of modifying the archway to extend the wall slightly if I have to. The chimney _is_ plaster/lath over brick. I'm not sure yet if the brick was painted before being plastered, but we'll find out soon enough. I'm planning on most likely leaving it exposed brick or covering in durock if we decide it's too ugly or doesn't look right. No, I think we should be able to leave a 6 inch clearance around the back and pipe side. After all, we want some circulation around it so it can heat the room. Now, in your first post you mention a half brick or full brick wall. Could you please elaborate on that part?

*Thank you* for your responses! Anyone that can offer help on this, it is _much_ appreciated! You wouldn't believe the time I've spent trying to figure this out. If you're in the Duluth, MN area, I'm definitely willing to *pay* to have this done. I can only hope. I've already tried the "yellow pages" route and can't seem to find competent help. Not surprising in this town, lol. So, thanks a million!


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## DangerMouse (Jul 17, 2008)

i'll just hop on my private jet and come there and help, no problems..... =o)

DM


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## Termite (Apr 13, 2008)

cart0181 said:


> You say I can get load bearing metal studs. Okay, I'll look for those. Would they have those at a standard home-improvement center? Also, how would I support the structure while I remove the wooden studs? Do I have to use a jack or something? Or is that unnecessary?


You won't find them at home centers. You'd need to go to a drywall and steel stud specialty supplier...Just about any average city has one or two to service commercial construction needs. 

Personally, I don't think that replacement of wall framing with steel studs is the way to go for most DIYers unless you have some very compentent assistance. To answer your "how do I support..." question, a temporary wall is normally built a couple feet away from the bearing wall to be removed/replaced, on either side of it. That wall will support the floor/roof above if done correctly. 

I wish I could offer a solution other than the addition of refractory firebrick with refractory mortar to the wall, but I can't.


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## DangerMouse (Jul 17, 2008)

mornin' kc! this is not that big of a problem, and there are lots of options to use. makes it much easier. =o)

DM


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## bjbatlanta (Jul 16, 2008)

Again, a drywall supply will have or can order the appropriate gauge studs (probably 16 ga.) As KC pointed out this may be a bit more than you want to take on as a DIY'er. Temporary support walls, are a MUST. You won't cut heavy gauge studs with tin snips.....you'll need a cutoff saw of some sort. Self tapping screws to hang the durock. Have you contacted your local building inspector or , even better, fire marshall for input?? They can tell you exactly what's required. If you're going to the extent you're considering, you should permit the job anyway. If for no other reason, to cover yourself from liability on down the line when you sell.


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## DangerMouse (Jul 17, 2008)

cart0181 said:


> @MdangermouseM-- I like your idea of modifying the archway to extend the wall slightly if I have to.


i meant to say if they go this route, there will be no need for the support wall, however, you all know my views on pulling a permit and having it inspected properly!

DM


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## userchuck1650 (May 27, 2009)

*DSA Inspector*

The flue pipe clearances needs to be considered also. The GA Fire Resistance Design Manual has a lot of valuable information.


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## sandeep (May 29, 2009)

:furious: refractory firebrick with refractory mortar is the only soultion.

wall can be supported by normal supporting soultions


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