Any region blessed with a high-quality building material in abundance, be that timber, stone, clay, etc., will naturally develop extraction, processing, and other value-adding commercial industries around this resource, for ‘export’ to surrounding regions and further afield. In isolated mountain villages and on remote islands, however, there may be no economical or practical way to get the resource or its products out to the wider world. This ‘landlocked’ condition, combined with the resource’s abundance, may mean that it has little or no commercial value, and so it will only be used locally, and in ways that might be considered wasteful in other circumstances, because there is no economic motivation to maximise yield and therefore profit. This has historically been the case in some regions of Japan in regards to timber, and has resulted in a floor framing method known as dai-neda-zukuri or о̄-neda-zukuri (大根太造り), ‘large joist construction’. In this method, the time-consuming work of rip-sawing and finishing many standard-dimension bearers (大引 о̄biki), joists (neda, 根太), and stumps (yuka-tsuka, 床束) is foregone in favour of fewer, larger-section joists, notched into similarly oversized, beam-like bearers which require fewer or no stumps to span between walls. Thick floorboards or planks are then fixed to these bearers and joists.
Floor framing showing large-section, beam-like bearers with few or no stumps supporting them, notched out to receive thick joists, which have been removed in this image.
An interesting comparison to о̄-neda-zukuri construction can be made with another variation in floor framing, this time a modern one only developed in recent years, known as neda-resu (根太レス) or neda-non (根太ノン) construction. Here, joists are entirely absent, replaced by 24, 28, or even 32mm thick structural plywood sheets fixed directly to a ‘lattice’ of bearers at 910mm centres in both directions.
On the left: standard modern Japanese floor framing consisting of bearers-joists-floorboards. On the right, a recent innovation, ‘joistless’ construction: thick structural plywood sheets laid directly on bi-directional bearers.
These two floor framing systems represent solutions to what are essentially inverted material and technological conditions, and could further be taken as representative of a characteristic difference between pre-industrial and industrial worlds. Whereas the conditions that gave rise to о̄-neda-zukuri method were the abundance of a resource (high quality, large-section timber) and the lack of technology required to fully exploit it (specifically the lack of technology required to extract and transport the timber economically), in the case of neda-resu construction, it is the scarcity of the resource, and the presence of the relatively sophisticated technology (peeling lathes, defect scanners, modern adhesives, hot presses, etc.) required to produce the structural plywood that makes the system both possible and economical.