I am building underground root cellar/emergency shelter - (PSP like Mike Oehler) in northern Alberta, Canada - (Gets to -35C / -31F for least a week each year - No cozy 52F underground for me in the winter - I'm praying for no colder than 35F) - I'm about 8 ft down, may be deeper the more earth I put on top.
I have a question about installing a wood stove. I installed one in my cabin so I know how to do it in a regular roof - my question is if it is the same for underground? It would mean that my spiffy double walled pipe was surrounded by earth for a foot or two. I can see that it might not rust, but wouldn't it be bad for the pipes to be underground? not like I could poly hot pipes...anyone have any thoughts on this?
Thanks,
Meagan

Are you planning on using double, insulated, stainless steel stove pipe?

I would think it would not rust, but maybe moisture problems in the insulation inside the pipe?

One way to get around that is to make a bigger sheet metal "pipe" to surround the stove pipe and keep the soil off. That could be galvanized steel or sturdy aluminum. Then put a collar on the stove pipe where it comes out, to keep water and crud out of the space. Or fill the space with micafill, available at most big box builder stores. It's used as pour in attic insulation. It's an expanded mineral and is totally fireproof.

Lot of trickiness here to keep water out where it doesn't belong, and nothing combustible close to the pipe.

HTH,

troy

Yes, double walled insulated steel pipe...The custom made large pipe might work but you're right and it would be the moisture that is a problem. I'd really like to know what other underground house builders have done. I have seen pictures of underground structures with stove pipes sticking out of the grass.
I could make a mini attic 1' x 1' with wood or earth bags covered in pond liner to extend the collar to above ground. They sell a metal box that goes between storeys to provide spacing through floors - I could use one of these, I suppose, through the "attic" but pictures would show my stove pipe coming out of a wood box - so others must have done something different.
Thanks for the advice!

I would like to try and revive this post.

I am considering constructing a outdoor rocket mass heater bench style with large rocks from my property. I'd like to carve out half circles in the underside of large stones to surround the pipe on the top side and carve the same half circles in the top of insulating kiln brick and insulating fabric on the bottom side.

Then I want a diversion valve at the barrel that can send the heat through a 25' straight pipe with 8" pipe 3' deep under a garden bed.

A garden and sitting area with a rocket mass heater making the area entirely functional in the winter in southern Missouri. The lowest we see is zero fahrenheit and that's rarely.

But I don't know what kinds of pipe I could use for either totally exposed under a rock or buried three feet under garden soil.

Any ideas would be greatly appreciated!