Kevin Olson

Eric -

Have you seen the Richard Hill Stickwood boiler?  This was from the bad old days of the oil crunch.

He was a professor at University of Maine, and developed a wood fired atmospheric boiler under a US Department of Energy grant.  It was quite similar to a J-tube, but used both forced and induced draft.  The best quality scan of his DOE report that I have found is here:
https://web.archive.org/web/20260122141201/http://www.hotandcold.tv/resources/woodfiredfurnace.pdf

He does give some details of the water tube boiler.  He batch fired the burner, stored the heat in two used fuel oil tanks, then pumped the hot water through his heating loop for a couple of days before firing again.  He had a small expansion tank in the attic, open to atmosphere.  This might give you a starting point for the boiler side, but using a J-tube as the burner.

I am currently investigating whether adding a home brew biomass burner - either pellets or cord wood - to a low pressure steam heating system (under 2psi, and with the new Vaporstat, maybe under 10 oz/in2) is possible - or wise.  I know I could do it by converting to a vapor system, but I am trying to come up with something that is a longer term off-grid solution.  I the power is out for a week because there is a big ice storm or the local substation in non-operative due to a mishap, I'd rather be the one with the house where all of the pensioner neighbors can keep warm than the one who is freezing right along with them.

I may end up just running a parallel heating system - RMH, or similar.

The Project Highlander YT channel has a discussion of these heaters:


He has a lot of other stuff likely to be of interest to Permie or Permie-adjacent types of folks, from log building to growing potatoes,

What about Erica Wisner's Caddis Fly design, here (about halfway down the page)?
https://ernieanderica.blogspot.com/2015/10/pyronauts-in-montana.html
or on Archive, in case of future link rot:
https://web.archive.org/web/20231001000000*/https://ernieanderica.blogspot.com/2015/10/pyronauts-in-montana.html
I think it's fair to characterize it as a pocket rocket with thermal mass.  She intended it for just such applications, though I don't know that she did any further development work on it after the initial collab at Wheaton Labs with Peter Van den Berg and others.

This is somewhat akin to a half-pint pönttöuuni, a Finnish heater built of bricks and/or fire bricks fitted inside a cylindrical steel skin, discussed in this thread, among other places:
https://permies.com/t/40876/ntt-uuni-metalcontainer-wood-burning

There were also small masonry heaters of quadrilateral footprint (as compact as 2X2 bricks - perhaps 16 to 18 inches or 400 to 500 mm square, depending on the size of bricks), apparently somewhat common as heaters for upper floor apartments in parts of the Eastern Bloc, which were built of common red bricks and sometimes fire bricks or specially shaped pre-cast refractory blocks, with a steel angle tension frame and having sheet steel skins slipped between the bricks and frame.  Since these were usually single skinned, due to the space constraints, the sheet steel shell gave some additional protection against leaks due to eventual cracks in the mortar joints.  David Lyle shows a plan for one or two of these small stoves in the appendix at the end of his masonry heater book, as I recall.  Some of the Soviet stove building manuals also detail such small masonry heaters, but I don't have the references at my fingertips.  With adequate framing, these might withstand some shifting and shimmying in a van.

Gustaf Edvard Asp also shows several smaller form factor masonry heaters built into steel shells in his book "Uuninmuuraaja" (I have a scan of the 1948 edition), though he does not appear to envision these in mobile applications (!).  There are both two and three pass contraflows shown which aren't far removed from Erica's Caddis Fly, give or take some height and a fuel door.  Erica's version is simpler, smaller, lighter and would be cheaper & easier to build.

Here is the scan of Appendix 3 of James Mitchell's book on Short Log and Timber construction, giving dimensions for various beam loadings, with a brief tutorial on computing simple loads.

Nate -

OK, so no snow loads to speak of until the next glaciation, but significant episodic wind loading.

James Mitchell gives scantlings for beams (i.e. rafters and purlins) in a table in Appendix 3 of his "Short Log and Timber Building Book".  I can probably scan that next week on the flatbed scanner at work (my flip phone doesn't take good enough pictures for legibility).  But, Mitchell is primarily concerned with snow loads, not wind loads.  Where I live, snow loads - up to 100 pounds per square foot, nominally, before all of the fudge factors are applied - are the primary consideration, as well.  He also has a good discussion of, among other things, foundations for permafrost locations (clearly not your principal concern either!), and computing roof loads for sod roofs.  His bog/swamp foundation discussion, though short, is worth a look and might be of interest in your neck of the woods.  This is a pretty accessible (non-specialist) reference, despite the fact that most of the book is about building modular post framed log buildings.  Used copies abound from the usual suspects and quite cheaply, since it's gone through multiple printings, so if you decide it's one for your bookshelf it shouldn't be too difficult to get one.

I also have an older edition (1974?) of the American Institute of Timber Construction's "Timber Construction Handbook" which gives some equations for wind load calculations as a function of wind velocity, roof slope, relative wind direction, etc.  It also has 50 and 100 year isotach maps, showing design wind speed for load calculations for the US.  Wind loads can either be positive (a push) or negative (a pull), and could be both a push on one side of a roof or wall combined with a pull on the other.  However, for open structures like your pavilion, the "Timber Construction Handbook" refers to a second publication, which I haven't yet tracked down.  So, I may need to dig a bit and see if I can hunt that one down.  External reference to a separate railroad engineering publication is also made for timber railroad trestles and the like.  But, I should also be able to scan the wind load calculation pages from the book I do have.

If you're in a hurry to get a reliable answer, directly consulting a structural engineer might be a good course of action.  But, my curiosity is now piqued regarding wind loads on open structures, so I'll see what I can find.  This might be generally useful information for others here on this forum, as well, for outdoor classrooms, carports, machinery sheds, hay storage, etc.  Or, even for buildings which will be constructed in stages, e.g. a timber framed structure which will subsequently have cob, adobe or cord wood infill, but will remain partially or fully open while the walls are closed in.

Please note that I am not a licensed professional engineer (PE) and none of the foregoing information should be taken as engineering services.

On the hunt...

Kevin

Another thought: perhaps the PER SQUARE FOOT values originally quoted are for LATERAL rather than VERTICAL loads (sorry for shouting, I am just trying to emphasize the differences!).

The quoted values are in what appears to be a reasonable range for lateral loading calculations when determining the embedment depth of poles for a conventional pole framed building, for a silty/clayey soil.  This would be for resisting wind loads, perhaps seismic loads, etc. for frames which have minimal diagonal bracing and rely on the pole embedment for racking strength.

However, I am pretty sure the values originally quoted in the units specified are too low for soil bearing strength.  Heck, rigid extruded polystyrene sheet insulation is good for 25psi, which is 3600 pounds per square foot (multiply the 25 by 144) compressive loading.

N.B. I am neither a civil nor structural engineer, and I don't have a Professional Engineer (PE) license.  Take all of this with a grain of salt.

Nate -

What are your nominal snow loads?  Any special wind loading considerations which attend this site?

Kevin

This paper from the British Medical Journal suggests that a regimen of one-legged hopping increases bone density in post-menopausal women, without exacerbating existing arthritic conditions:
https://onlinelibrary.wiley.com/doi/full/10.1002/jbmr.3867
There's a link to download a PDF, but I couldn't get it to load on my laptop.

However, women with very low bone density were excluded from the study (presumably, the risk of fracture was too great if the bones were sufficiently weakened), as were women with existing injuries or excessive BMI.

Table 1 of the paper enumerates the 6 month long protocol used in the study, gradually progressing from lower intensity to higher.

But, polka dancing would probably be more fun!  Or, hopscotch...

As I'd alluded to in the comment on the Livestream YT video, here's the scan of the table of soil bearing capacities from Seddon's 1985 book "Practical Pole Building Construction".

On further edit, here's the link to the livestream, for ease of access:

My comment shouldn't be too difficult to find there , but here's the copy/paste of what I wrote there, to make this thread more stand-alone, should the YT comments evaporate or something:

"I think there's likely a units problem in the soil bearing capacity specs being quoted, though I don't know where the error crept in.

I checked my copy of "Practical Pole Building Construction" by Leigh Seddon (mine is the first edition 1985 copy write).  In Table 5-2 (page 57), the soil bearing capacities range from 1500 to 6000 pounds PER SQUARE INCH, depending on soil type.  For the rocky soil shown in the photos, I'd think the bearing capacity would be close to the higher limit, but a soil analysis - even just shaking up some of the soil with water in a glass jar and letting it settle for a few days - might give a more definitive answer regarding soil composition and thus allow better inferences to be drawn regarding the safe bearing capacity value for this design.

In any case, I think the 1500 pounds PER SQUARE FOOT is off by a factor of 144 (that's how many square inches are in a square foot), and probably by some additional factor due to the local soil having higher bearing capacity than poorly drained plastic clays and silts to which the lower 1500 psi value applies.

Seddon says that typical pole loading is usually between 6000 and 12000 pounds.  So, the 19000-ish pounds is high, but not crazy high.  A large enough diameter pole of a decent (structural) grade should be able to safely take that load.

Many historic New York City high rises are built on wooden pile foundations, "driven to refusal", somewhat like pushing down on the poles with the excavator, though a pile driver is typically used when driving piles for foundations.

I'll try to post a scan of Seddon's Table 5-2 on the Permies forum in the thread, for reference."

Hopefully this is helpful to someone, whether building a wofati, boat house or pole barn.

Brownberry Health Nut and Orowheat were mentioned upthread, and I definitely remember those.  After I was a bit older, my mother could sometimes get the Health Nut bread from the returned bread store.  Sometimes slightly stale Egekvist doughnuts, too, though not very often.  Also English muffins from the returned bread store, If I recall correctly.

My mother did make bread "from scratch" - mostly white, sometimes "whole wheat", meaning store bought whole wheat flour, so not truly whole meal - and later, when she had more kids to wrangle (and I'm sure I needed more than my fair share of wrangling!) and less time, the frozen loaves of dough from the freezer section at the supermarket, to be thawed, raised and baked at home.  I remember having the "heel" toasted, with butter, cinnamon and sugar, as an after school snack.

She often made quick breads from scratch: corn bread, sometimes in a muffin pan, sometimes baked in an 11X13 pan; muffins (banana nut, with pieces of walnut and made with overly ripe bananas) or quick bread loaves (less monkeying around than with greasing or lining the muffin pans); scratch made pancakes or waffles (waffles often had a white gravy, with chicken or tuna, onion and small green peas - only rarely with jam or syrup).  Baking powder biscuits were also pretty common, sometimes with the white meat gravy, as for waffles.  I think she mostly used Bisquick for biscuits when I got older, but I am fairly certain they were made "from scratch" when I was younger, because I remember the "Clabber Girl" can.

My paternal grandmother always had Siljan Rye Crisp when we visited her.  Rye crisp still takes me back to those days.  After I had graduated from university with an engineering degree, I worked nights at a grocery store, stocking shelves (engineering jobs lying pretty thinly on the ground, in those days), and I would buy a loaf of cocktail rye and make a zillion tiny rye bread and sharp Cheddar cheese sandwiches - so good!  With or without caraway, I'm a fan of rye.

These days, I'm on a low carb/keto diet for a specific health reason, so I don't eat bread very often, though I am hoping to get back into making whole meal bread from home ground whole meal flour.