Does adding plaster to drywall count?

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JRP3

Feeling the Heat
Hearth Supporter
Sep 17, 2007
343
NYS
For the wall near the wood stove in my garage I put up 1/2 inch drywall but it seems code is for 5/8, can I add 1/8 of plaster on top, or another layer of 1/2, or should I just add a layer of 5/8 over existing 1/2?
 
For the wall near the wood stove in my garage I put up 1/2 inch drywall but it seems code is for 5/8, can I add 1/8 of plaster on top, or another layer of 1/2, or should I just add a layer of 5/8 over existing 1/2?
A woodstove can never meet code in a garage in the USA regardless
 
not if there is anytime gas or gasoline etc. in there, whether in a car, lawnmower, or jerrycans.

IF you do it (you'd not be the only one), I suggest you look up Canadian code that does allow it - as long as the stove is set a certain height above the floor (1ft?).

What is the code for that specifies drywall thickness? (it's not clearances, as the paper on the drywall already is flammable...)
 
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The only car I regularly keep in it is electric. I don't store gas cans in there.

Google AI said 5/8 Type X drywall.
For a wood stove installation, you need Type X 5/8-inch fire-rated drywall, often used in multiple layers or with a heat shield (like metal/cement board with an air gap) to meet safety codes,
I also added a metal shield with spacers to the side of the stove. I think the firebox is more than 12 inches off the floor, the stove feet are on 8 inch cinder blocks.
 
The only thing that matters is how far the combustibles are from the stove - and that depends on the stove model (see its manual; for unlisted stoves its 3 ft ! - that can be cut to 1 ft using an approved heat shield spaced 1" of the wall and with a 1" gap at the bottom and open at the top to allow for convection to carry away the heat).

The paper on the drywall is the first combustible the heat sees, and the clearance distance is therefore the distance to the paper facing.
Add more drywall means your combustibles end up 1/2" closer to the stove each time. So that's not advisable.

Methinks Google AI is hallucinating.
 
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The clearance to combustibles is the determining factor. Adding plaster doesn't change this. What stove is this for, a UL listed stove or an unlisted old stove.

The electric car question is interesting one. Rules will be changing I think.
 
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A proper, ventilated, NFPA 211 wall shield will allow the stove to be within 12" of the combustibles behind that shield.
 
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I'd still add that 5/8 over the existing. Yes, the face is combustible, so you'd need something like begreen mentions, but when it comes to actually spreading a fire, the 5/8 drywall is going to slow it down much better than a half inch. 5/8 over 1/2 is even better.

That doesn't affect code clearance, just actual fire spread.
 
that can be cut to 1 ft using an approved heat shield spaced 1" of the wall and with a 1" gap at the bottom and open at the top
Can those gaps be larger than 1 inch? Since the stove is 14 inches off the floor and is only about 2 ft tall does the shield need to go from floor to ceiling, minus the 1 inch gaps, or can it be less?
 
Yes they can. Minimum of 1".

The shield does not need to go to the ceiling. I'm not sure what the exact requirement is, but I would put it 1 ft taller than the top of the stove. That is aesthetically acceptable imo.
 
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Thinking of something like this, stove is in a corner, angle top of the shield on the left to help reflect some heat into the room, back wall shield would be straight since it's further away. Green circle is a wood stove powered fan, pointed at the stove pipe in reality.

[Hearth.com] Does adding plaster to drywall count?
 
The angled shield won't make an appreciable difference imo.

I would not point the fan to the pipe unless you don't have a baffle in the stove (i.e. you're pushing too much heat up the pipe).

Then, your insurance may not pay out of something happens with the garage if you have a stove there. Just be aware ..
 
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I would not point the fan to the pipe unless you don't have a baffle in the stove (i.e. you're pushing too much heat up the pipe).
Stove only has a small baffle, and the fan isn't very powerful.
Then, your insurance may not pay out of something happens with the garage if you have a stove there. Just be aware ..
Yes that is a consideration.
 
If this is one of those small TEG thermal fans try to keep it away from the hottest parts of the stovetop. Getting them too hot can reduce performance permanently. Stick within the recommended operating temperature range.
 
Note that the reduction to 12" from combustibles with the shield applies to the stove.
If you have single wall pipe, that has a larger clearance.
I do not know if wall shielding (i.e. running it up to the ceiling) is okay to reduce pipe clearances?
@begreen ?
 
If this is one of those small TEG thermal fans try to keep it away from the hottest parts of the stovetop. Getting them too hot can reduce performance permanently. Stick within the recommended operating temperature range.
unless this is one with a bimetallic spring at the bottom that lifts off the fan from the stove top when it gets too hot :-)
Fool proof safety that really works!
 
Check the bottom. If it looks a bit like this, it has its own overheating safety:
[Hearth.com] Does adding plaster to drywall count?

That light strip is a bimetallic piece that bends when it gets hot. In doing so it lifts the bottom partly off of the stove top, allowing less heat in the metal frame and traveling up to the thermoelectric element.

Still, of course, if you have the rating of your specific model (rather than some generic one), that is the thing to go by.
Most of these die before 650 F (over time; not immediately), so I assume yours has the bimetallic piece.
 
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Note that the reduction to 12" from combustibles with the shield applies to the stove.
If you have single wall pipe, that has a larger clearance.
Looks like single wall needs 18" of clearance so with the side of the stove at 16" from the wall the pipe would be more than 18" away. Rear is set even further away from the wall.
 
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I got it at a garage sale years ago, it looks like this, which says it's good to 650F
That's a good one. Mine lasted for several years. I'm not sure about the newer ones but the original Caframos did not have thermal protection.

I just checked, one of my new Amazon (China) thermal fans has protection and the other does not.
 
I was curious so ran out to the garage, it's an Eco Fan Model 810, no strip on the bottom.
 
I see Durock cement board has no paper face and has a higher fire rating than drywall, I might use that to replace the drywall before putting on the metal shield.
 
If the durock is mounted on lumber studs, you only gain 1/2".

If you are meeting clearance, you can use any normal building material. Fine to use durock but not needed.

I don't even know what a "higher fire rating " means. What matters is that it's not combustible.
One can have an application temperature range but that has nothing to do with fire.