Installation Design Advice for a Small Cabin

[ChainsawDave]

Hi everyone! So I've got all the components for my install and have a couple questions about clearances.
My stove is an HQ issue tent stove (I know it's not ideal but i figure if I follow the advice for un-certified stoves, it can be done safely). The stove is in a corner but also partially boxed in on a third side by a counter. The drawing was made in sketch up so the dimensions are very close to actual.

My questions are:
1. Anyone see an issue using a flattened out 55 gallon metal drum for heat shield? I've burned the paint off, cut them apart, and driven over them to flatten them.
2. Is there any reason the heat shield has to be one contiguous piece? The way I've got things worked out, barrel steel, metal roofing and sheet metal can't be found in big enough sizes to completely cover the wall space required.
3. I've read the heat shield fasteners should be on the edges of the shield but what about my shield that protects the counter? The counters front facing edge is about even with the middle of the stove (hard to describe, see picture). Even the fasteners in the corner seem a bit close to the stove. My concern is conduction through the fasteners into the wood.
4. I've found different advice as well as read the NFPA 211 sections concerning heat shield size. If anything combustible within 3' needs a shield, that makes the shield way huger than anything I've ever seen. None of the diagrams I've checked are even close to scale and distort the reality of this. You can see in my pic just how large that makes the shield. On google image searches, I've seen many antique stoves where the shielding is not as large as this (maybe a lot of people just do it wrong). Woodheat.org says to go 18" horizontal from each edge of the stove and 20" above the stove height. That seems more reasonable to me. Both sizes of heat shield I'm comparing here are shown in the drawing.

I think that's it for now. I left some details out to try and shorten the post. Let me know if my posting style is annoying and what I can do to make it easier to get help.

Thanks!
Dave

 

[begreen]

Welcome Dave. Yes, the stove needs a clearance of 36" in all direction. A proper, ventilated NFPA 211 wall shield can reduce the rear and side clearance to 12". The wall shield can be made out of sheet metal which comes in 4 x 8 and 4x10 sheets. It does not have to be one continuous sheet. There can be a joint in the corner for example. The shield needs to be open at the top and bottom by 1" so that air can freely convect behind the shield. The counter end needs the same protection.

This setup is far from ideal. It would be good to consider another location for the stove, or moving or shortening the counter by a cabinet width.

 

[sprawlnstall]

Hi everyone! So I've got all the components for my install and have a couple questions about clearances.
My stove is an HQ issue tent stove (I know it's not ideal but i figure if I follow the advice for un-certified stoves, it can be done safely). The stove is in a corner but also partially boxed in on a third side by a counter. The drawing was made in sketch up so the dimensions are very close to actual.

My questions are:
1. Anyone see an issue using a flattened out 55 gallon metal drum for heat shield? I've burned the paint off, cut them apart, and driven over them to flatten them.
2. Is there any reason the heat shield has to be one contiguous piece? The way I've got things worked out, barrel steel, metal roofing and sheet metal can't be found in big enough sizes to completely cover the wall space required.
3. I've read the heat shield fasteners should be on the edges of the shield but what about my shield that protects the counter? The counters front facing edge is about even with the middle of the stove (hard to describe, see picture). Even the fasteners in the corner seem a bit close to the stove. My concern is conduction through the fasteners into the wood.
4. I've found different advice as well as read the NFPA 211 sections concerning heat shield size. If anything combustible within 3' needs a shield, that makes the shield way huger than anything I've ever seen. None of the diagrams I've checked are even close to scale and distort the reality of this. You can see in my pic just how large that makes the shield. On google image searches, I've seen many antique stoves where the shielding is not as large as this (maybe a lot of people just do it wrong). Woodheat.org says to go 18" horizontal from each edge of the stove and 20" above the stove height. That seems more reasonable to me. Both sizes of heat shield I'm comparing here are shown in the drawing.

I think that's it for now. I left some details out to try and shorten the post. Let me know if my posting style is annoying and what I can do to make it easier to get help.

Thanks!
Dave
View attachment 222067

Dave, I've burned many cords of wood with this stove in my Ice House here in Minnesota. The 55 gallon drum flattened out would probably work, but sounds like a lot of work. A piece of cement board would cost you 10 bucks and would do the job. Just an FYI before you install the stove. The piping is an odd size I believe 3 3/8 inch. A typical wall / roof thimble will not fit well. Also you cannot find extra pipe for the stove. I welded a 4 inch collar on the stove so I could use 4 inch pipe. The stove works great indoors but is marketed as an outdoor stove. You will want the stove close to the floor unless you are using a fan. Hope this helps.

 

[begreen]

Yes, it's actually against the law to sell it as an indoor stove.

 

[ChainsawDave]

Welcome Dave. Yes, the stove needs a clearance of 36" in all direction. A proper, ventilated NFPA 211 wall shield can reduce the rear and side clearance to 12". The wall shield can be made out of sheet metal which comes in 4 x 8 and 4x10 sheets. It does not have to be one continuous sheet. There can be a joint in the corner for example. The shield needs to be open at the top and bottom by 1" so that air can freely convect behind the shield. The counter end needs the same protection.

This setup is far from ideal. It would be good to consider another location for the stove, or moving or shortening the counter by a cabinet width.

Thanks for the reply Begreen. I still don’t understand why people say so many different things regarding clearances. I don’t see anything in the NFPA 211 that talks about shield extension above and on the sides of the stove. 36’’ in all directions makes sense considering radiant heat flow in all directions. However I just haven’t seen any examples of people going this far. Holding the tape measure up, it just seems ridiculously huge. I haven't seen any pictures of installs with shields this immense. Or maybe the pictures are just deceiving me.

For 3’ in all directions that makes the shield on one wall 5’ 9” by 5’. I understand there can be a joint in the corner but if the sheet metal is only 4’ wide, I’d need a seem closer to the middle on each side. This would place fasteners closer to the stove. I guess what I’m really worried about is the conduction through the fasteners. The fasteners on the edge of the counter would line up with the middle of the stove as well.

The reason I wanted to use the barrels is because they are cheaper than sheet metal, I already have a couple and I thought cement board didn’t allow for as much clearance reduction.

I’ve got everything positioned this way because the cabin is so small.

 

[begreen]

Don't worry about heat conduction through the fasteners. The heat will be dissipated by the sheet of metal so that the amount of heat conducted via the screw is trivial. Cement board works fine as a heat barrier, same clearance reduction. Use durock nexgen to keep the weight down. You can snap off 3" wide strips and double them up to create 1" thick furring strips that attach vertically to the wall studs as spacers.

 

[ChainsawDave]

Dave, I've burned many cords of wood with this stove in my Ice House here in Minnesota. The 55 gallon drum flattened out would probably work, but sounds like a lot of work. A piece of cement board would cost you 10 bucks and would do the job. Just an FYI before you install the stove. The piping is an odd size I believe 3 3/8 inch. A typical wall / roof thimble will not fit well. Also you cannot find extra pipe for the stove. I welded a 4 inch collar on the stove so I could use 4 inch pipe. The stove works great indoors but is marketed as an outdoor stove. You will want the stove close to the floor unless you are using a fan. Hope this helps.

Hi sprawinstall. Good to know someone else uses this stove in a similar way. I just don’t have the money for a proper tiny home stove. I’d go with the cement board but doesn’t sheet metal allow greater clearance? My cabin is really tiny.

For the stove pipe I’m planning on getting a 6” to 4” stove pipe adapter and then a stainless steel exhaust adapter to go from 4” to 3 3/8”. They make a lot of sizes of the exhaust parts and I figured if there was a small gap I could use stove cement on it.

 

[ChainsawDave]

Don't worry about heat conduction through the fasteners. The heat will be dissipated by the sheet of metal so that the amount of heat conducted via the screw is trivial. Cement board works fine as a heat barrier, same clearance reduction. Use durock nexgen to keep the weight down. You can snap off 3" wide strips and double them up to create 1" thick furring strips that attach vertically to the wall studs as spacers.

Thanks, that puts this issue to rest for me. Sprawinstall says put it closer to the floor in the post above. I was propping it up on cap blocks to get it 18” off the floor. I based on what I read in this link you posted on another thread a while back (Proper Installation, Operation and Maintenance of a Wood Stove). It’s hard to feed and tend being so low to the ground and 18" high reduces the the materials for the floor pad.

With 3’ to combustibles addressing the radiant heat, why is the floor not a part of this? The 18” of floor pad in front of the stove is not enough protection for the 3’ in all directions rule. If I put it closer to the ground it will be in the 6" to 18" range on the chart below. According to your expertise, should I just go with what this chart says?

 

[sprawlnstall]

As long as you have the stove resting on some sort of fire barrier such as concrete you shouldn’t have to worry about the floor getting hot the 18 inches in front is for spark protection. I originally had this stove 18 inches off the ground the problem was the 18 inches below the stove was around 30 degrees and the ceiling was 80 degrees. No joke.

 

[ChainsawDave]

As long as you have the stove resting on some sort of fire barrier such as concrete you shouldn’t have to worry about the floor getting hot the 18 inches in front is for spark protection. I originally had this stove 18 inches off the ground the problem was the 18 inches below the stove was around 30 degrees and the ceiling was 80 degrees. No joke.

Cool! Literally. Sounds like you have about the same amount of insulation as I do, which is none. Do you have any wall shielding?

 

[sprawlnstall]

I have some class 1 fireboard on the wall basically cardboard with a thin fire retardant surface. I’m not exactly how far it is away from the wall but I’m guessing a foot. My ice house is 7x10 with 1.5 inches of insulation in the walls and ceiling, none in floor. I have the stove in the corner similar to your pic. I have been very happy with the stove it puts out a lot of heat, I can easily get my fishouse to 90 degrees when it is -30 below. I have loaded it with dry seasoned oak and it has held up well. I got a very slight bulge on the top from burning it too hot but i can still cook on top. It does burn through wood, expect 2-3 hour burns.

 

[ChainsawDave]

I have some class 1 fireboard on the wall basically cardboard with a thin fire retardant surface. I’m not exactly how far it is away from the wall but I’m guessing a foot. My ice house is 7x10 with 1.5 inches of insulation in the walls and ceiling, none in floor. I have the stove in the corner similar to your pic. I have been very happy with the stove it puts out a lot of heat, I can easily get my fishouse to 90 degrees when it is -30 below. I have loaded it with dry seasoned oak and it has held up well. I got a very slight bulge on the top from burning it too hot but i can still cook on top. It does burn through wood, expect 2-3 hour burns.

Minnesota sounds brutal. I thought we had it bad with single digits for a few weeks. Thanks for the info. Nice to know the stove does the job for you in those conditions.