Every building technology is ultimately a compromise. Hundreds of factors weigh in. Faced with similar situations, vastly different cultures will reach the same conclusions: take the thatched roofs of the N. Atlantic Hebrides and those of Jeju Island in the Korea Strait for ex.
Both areas are characterized mostly by strong winds and relatively meager soils. Hence roofs were thatched (which grows amply on poor soils) and built with a low angle (nearly flat) with an oblong shape weighed or tied down with a net of rope to minimize the effect of winds.
Normally the primary purpose of a roof is to shed water but here that job had to take second place: longevity is sacrificed in order to ensure that roofs can survived hurricane or typhoon strength winds. Rain permeates the thatch so in the case of Jeju, they only last 1-2 years.
The short lifespan of a Jeju roof is no problem. Nature has provided it so neatly that the thatch used is best cut in December when agricultural activity is at a nadir. Anyone can help, technically simple, the ropes of an average roof for example take four people one day to make.
Another bonus is that the thatch is perfect in the hot and humid summers with cold winters on Jeju Island: the thatch keeps the summer heat from penetrating into the interior of the home and in winter it isolates the heat from people and stoves.
When the roof is relaid the bad parts are thrown out and the new thatch easily spread over the existing roof. Nothing goes to waste: the old thatch is thrown into the household pigpen where it mixes with manure and is then carted to the fields and gardens to make free fertilizer.
But the final bonus is that the very act of thatching a roof becomes a communal village event where people get together and help each other, strengthening the ropes on your neighbor's house literally strengthens the bonds between your families. This is mostly a lost art today.
The houses of Jeju Island are interesting: clustered together in villages as walled family compounds. The walls are to keep cattle and wind out, for gardening purposes. One house is the the young family and a rear house is given over to the older generation.
The walls are built out of black volcanic rocks with the local red soil as a clay mortar. The gates have three poles: one pole in place means the household is out for little, two means out for the day, three means out for a long period of time.
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It is well known warehouses built in earth plaster using inoculated fermented straw and soil keeps fruits, vegetables fresh longer and inhibits mold and microbial growth on paper, books, clothes, antiques etc. Hence Japanese "Dozō". But you can build miniature storage boxes too.
A Japanese master plasterer designed boxes built exactly like regular earthen warehouse walls, except he reused wooden wine crates. He sells kits, or you can use your own materials to make your own if you feel up to it.
These boxes are intended for grain, vegetables and fruit that you would normally keep in a "dark and cool" place. And they work. Here is a comparison with a polystyrene box and three mandarin oranges after 45 days. The blue box is more like what most modern homes are built like.
The practical skills in thatching can be difficult to acquire by videos or books alone, especially how to find materials and the binding. In Finland there is a traditional thatching technique that uses only easy to find reed and no binding: just spread it out and weigh it down.
A bound reed roof is far steeper and thus lasts longer, but it requires more skill to do correctly. Reed is often available for free and in vast quantities anywhere it grows, harvesting it is doing nature a favor. All materials used in a reed roof are compostable, all hand tools.
For a standard roof of say 100m² you need to harvest about three hectares. You can harvest that by hand in about a month, or in a day if you have a reed harvesting machine. In Finland you harvest in March, April.
Maybe one of the oddest professions in Japan is that of the bokka (歩荷). Porters who carry supplies to remote mountain guesthouses inaccessible to vehicles. A bokka uses customized wooden ladder frames to carry 100-165kg of supplies on day long marches (walk up, run down).
The job is popular: not surprisingly veteran bokka routinely tests as fitter and healthier than elite athletes. Both men and women take on the job, the average weight of a bokka is 60-70kg.
Still not much of a chore compared to what some farmers used to handle.
Iriairinya (入会林野) is the Japanese term for "commons". In the West the term "commons" are usually meant as fields for grazing but Japanese commons were traditionally the mixed grass and forest lands between mountains and flatlands usable in agriculture.
Iriairinya are typically from a couple of hectares up to 50-60 hectares. Still a valid legal concept, village's who manage commons also have the option to incorporate them (as modern organizations), to make them more compatible with modern legal practices.
Commons were meant to be vital lifelines for rural villages, providing its members with food (forage), feed (for livestock), fertilizer (leaves), fuel (wood, charcoal), building material (roof thatch). When modern lifestyles took over in the 1970s commons were mostly abandoned.
The miracle of Usami: at 11:58 A.M. Sept. 1st 1923 a great earthquake struck the Tokyo region. Near the epicenter was Usami village, where no one was killed or injured while neighboring villages each had hundreds dead and wounded. How?
The villagers of Usami had an exceptionally long memory. Records, monuments and tales of a huge 1703 quake had been preserved and stories of what happened was still in vivid memory. The locals acted unbelievably fast, evacuations started as soon as the trembling stopped.
An 8m tsunami struck the seaside village only 5 min after the quake. Locals were already arrived at and safe within historical evacuation grounds: temples, bamboo thickets, stands of trees, where their ancestors had marked out safe spots centuries before (circle: 1703 tsunami)
The post town Tsumago-Juku (pop 400) in Japan was founded in 1601. In 1960 it took a unique decision to dedicate itself to its own preservation by three golden rules: "No selling, no letting, no destroying." Every renovation or rebuilding even of private homes is done in common.
The town's main income is obviously tourism, but in order to preserve the town the locals figured out a method where they build and renovate as much as possible by themselves, together. One ex. is the town's six remaining "ancient style" ishiokiyane: shingle roofs held by rocks.
The roofs are made of wood shingles, only the bottom row nailed, the rest held down by horizontal battens and rocks. They are relaid every few years, broken shingles discarded, leaks fixed etc. Work is led by the most skilled townsperson while a team of 5-20 volunteers help out.