Glenn Herbert

I would consider a layer of light sraw-clay for modest insulation needs. Build a cob wall as thick as structurally necessary but no more for the inside, then apply a layer of LSC which dries rigid, then plaster over that. The LSC can be sculpted as desired for the outside form.

I would guarantee that 16 gauge would be strong enough to hold up without waffling or buckling. 20 gauge would probably be strong enough. It depends in large part on the span between bends - what is the width of your planned bell?

I would recommend galvanized steel for the sides at least, to minimize rusting. High-temperature stove paint might protect plain steel well enough. The top will get hot enough over the riser to burn off galvanizing, so heavy steel or stainless steel would be the way I would go for that.

The speed of heating up is pretty much irrelevant - any sheet metal gauge is going to be hot in minutes. My 1/8" steel access panel in my bell gets warm within a few minutes of starting a fire, and it is mostly below the level of the riser top.

I love the name "fally downy building", even though it seems to be doing a good job of not (yet) falling down. When my wife wanted to add a roofed deck and future animal space to the back of her house, the then 4 or 5 year old grandkids called it the "barn house"... it is still that.

I think the building is good enough to save, but not enough to spend a lot on upgrading. The beams and rafters are ridiculously badly done; the beams need to be reinforced and possibly straightened, while the rafters can probably work for a long time without modification as long as bounciness is not a major problem.

If you want to straighten the beams for looks or to protect the (replacement) roofing panels, you can make a crude but effective jack with a stiff post just an inch or two longer than the distance from floor to desired height. Put a strong smooth plank on the floor in line with the beam so that you can position the jack post at an angle while touching the center of the beam bottom. Fasten it to the beam so it can't slip but can bend. Hammer the bottom of the brace along the plank to slowly raise the beam to the desired height. Two braces working in opposite directions may make this easier and more secure. Once the brace has straightened the beam, sister on a 2x10 or 2x12, or a pair of them on each side of the beam, depending on how strong it needs to be. You might need to temporarily disconnect the diagonal braces so the beam can flex freely, then reattach them to the new sister beams.

You can use the same method to temporarily raise and support any posts that need to be repaired at the bottom. Lifting the post base just clear of the footing will allow you to clear or replace rotted wood, reinforce the concrete if necessary, insert flashing on top of the concrete, and lower the post back onto the footing. With a small hammer drill you can sink lag bolts into the concrete to tie the posts to the footings. The structure is light enough that this process should not be dangerous.

Once the structure is firmed up, you can determine if the existing roofing can be repaired or if it needs to be replaced.

Excellent idea! I don't know how practical it would be in real life, but worth exploring. I would try a drainback system, where the water all sits inside the house until the collector is warm enough to give net heating. Then a pump circulates water through the collector and back to storage. No water is exposed to freezing temperatures.

You can build an energy-efficient house anywhere, as long as you match materials and techniques to the environment. In your case, that would first mean making the house higher than ground level. How much this requires depends on the specifics of your location in the flood plain. I am sure you could build an earthship starting with a mound and adding earth around the sides, but that would probably not be the most energy-efficient method of construction in your circumstances. Obviously you will not be able to dig into the south side of a hill. Aside from that, I don't think there is anything specific to advise that is not primarily based on your geographical and cultural region. I don't think coastal Maryland has long-established climate-specific traditions as some regions have, so I would look to literature on effective methods and designs in general. That can give much more thorough advice than a forum thread can.

Since I am not experienced with root cellars yet, I will bow to accumulated knowledge about floors and humidity. I presume you would want moisture/vapor resistant materials to keep humidity from affecting the floor structure above.

Radon investigation would be a good starting point, but if that does not prove to be an issue, I would start with a floor slab in the cold room (no deeper than you need for headroom) and put up a concrete block wall to main floor slab level. Many concrete companies have minimum batch delivery sizes and you would not have to pay a premium for a small amount of concrete. Interior basement walls that are relatively compact and not subject to frost heaving do not need to be reinforced concrete. Running vertical rebar in a few cores spaced across each wall and filling those cores with concrete will give plenty of strength for insurance. I like dry stacking block and surface bonding on both sides - as strong as ordinary mortared joints and much faster. Then backfill around the finished cold room walls (with vapor barrier) and pour your main floor slab.

Downward fire needs something forcing it to move downward, like a vertical chimney which creates draft. I cannot imagine that a fire would start in a cold system and move downward.

12 years ago there was much made of the idea that an RMH does not need a chimney; this was the case in Ianto Evans' location on the Oregon coast with a constant prevailing breeze in one direction and the exhaust on the downwind side, but will not be true in most locations in the world.

J-tube combustion cores are indeed reputed to be tricky in 4" sizes, but batch box combustion technology does scale up or down reliably, and moreover gives considerably more heat in the same burning time than a J-tube system of the same size.

If you can't or won't run a vertical chimney through the roof, which gives the best results, I would go through the wall as high as you safely can to increase your chances of success. A long cold exterior chimney can cause cold plugs in certain circumstances and make it impossible to get draft started without going outside and preheating the chimney.

Once you confirm that the flue does not leak and is sound, I think you will be good to go. The exhaust temperature will be much lower than a standard wood fired combustion unit, so it should be safe.

I think the practicality of wood burning for heat depends on what your house and equipment are like. If you have a big leaky house and a big stove that is not very efficient, the work involved could be overwhelming. If you have a well insulated house and a very efficient stove or best of all an RMH, the wood processing could be easily manageable.