Clearance To Combustibles / Wall Heat Shield ???

[Peter B.]

I'm still burning in an antique stove that's been internally modified (including a catalyst) for improved efficiency.

This will be the twentieth winter I've used the stove in the same location. Only recently have I become concerned about the clearance to the combustible wall (painted wood wainscoting) behind the stove.

The clearance is only 20 inches, when for a non-UL listed stove, I believe a nominal 36 inches is recommended.

I've read here that (roughly) 185* degrees is the highest wall surface temperature allowed when stove manufacturers set their minimum clearance recommendations... and that 185* is about 50* above the threshold at which you can comfortably hold your hand on the surface.

With a good hot fire going, I can still rest my hand on the warmest part of the wall without discomfort.

Should I be concerned? Enough that a heat shield should be installed? Even after twenty years without a problem?

If so, I'm not clear on the common materials used. Are Durock and cement board the same thing? Are either/both commonly available at lumber yards and such? Are other materials preferable?

Northern Tools has a wall heat shield listed for about $60. Will I do a LOT better buying 'raw' materials instead?

Thanks for your time...

Peter B.

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[begreen]

If the stove has been burning hot for hours and you can still hold you palm against the hottest wall spot for a while without any discomfort it is probably very safe, or you have gloves on. ;-)

However, if you want peace of mind, then a wall shield won't hurt. For tiling, cement board sold as durock or wonderboard brand are the preferred underlayment. But it can be metal as well. Perhaps you could find some old tin ceiling tiles and mount them with an air space?

 

[Peter B.]

Thanks BeGreen...

(You being very strict about install considerations, I might have thought you'd shoot me down.)

Nope, no gloves, no sleight of hand... and yes, the wall is hot, but (again) not so hot I can't rest my hand on it.

I'll continue to monitor the wall 'by touch temp' and see what it's like when the stove has been at max for a longer period... but I think what I tried is representative.

And I don't need more heat today... from just below zero last night to 20* currently... with sunshine on the south wall... easy street.

Peter B.

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Edit - Nice thought about the tin ceiling tiles... a friend used some a number of years back.

Some form of wall shield is not out of the question in future... I just didn't want to worry about it so much this winter.

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[fossil]

NFPA 211 says 36", but that's a "standard", not a "code", unless adopted as such by the local Authority Having Jurisdiction. The standard goes on to detail proper construction and installation of a wall heat shield. There are a number of options on exactly how to do it. I, too, thought of the stamped steel or tin ceiling tiles when I was thinking about your old stove. Myzamboni has a very elegant and simple shield of a single sheet of stainless steel spaced from the wall (buys him a 66% reduction in CTC). I find it stunning, but you might not like that look with an antique heater. I'd say keep an eye (or a hand) on it and if a wall shield of some sort would make you more confortable, then work out a design that will please you and git 'er done. The possibilities are almost endless when you start looking at ceramic or porcelain tiles over Durock. Rick

 

[begreen]

Thanks BeGreen...

(You being very strict about install considerations, I might have thought you'd shoot me down.)

Nope, no gloves, no sleight of hand... and yes, the wall is hot, but (again) not so hot I can't rest my hand on it.

I'll continue to monitor the wall 'by touch temp' and see what it's like when the stove has been at max for a longer period... but I think what I tried is representative.

And I don't need more heat today... from just below zero last night to 20* currently... with sunshine on the south wall... easy street.

Peter B.

--

Edit - Nice thought about the tin ceiling tiles... a friend used some a number of years back.

Some form of wall shield is not out of the question in future... I just didn't want to worry about it so much this winter.

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I figure any guy that's been burning in the same stove for decades must know what he is doing. Especially when he's performed some pretty elegant mods and upkeep to bring the stove up to modern age standards without destroying its good looks.

Based on the hand on the wall test I would guess it might be somewhere in the 120-140 deg range. Some of that tin is not cheap, but if you shop around who knows what you might find. A sheet of blued sheet steel might look great too.

get out the paint remover:
http://www.goantiques.com/detail,100-square-foot,2123528.html
or the wallet :
(broken link removed)