It’s essential that we develop architecture that adapts to climate change

Mass timber” building materials made from laminated wood, invented in recent decades, have made significant advances in terms of strength, quality, and possible applications.. Cross Laminated Timber (CLT), for instance, which was invented in Austria in the mid-1990s, has demonstrated great performance potential for the construction of large buildings. CLT-based structures are currently being used in buildings with up to 18 stories in many parts of the world. CLT generally consists of a number of wood layers glued together to form solid panels with a thickness normally ranging from 60 to 320 millimeters. The key to the success of Mass Timber, especially for modular prefabricated structures, lies in the material’s intrinsic sustainability, the rapid building process, and great flexibility of use. Equally importantly, wood materials store carbon, thereby minimizing negative climate effects. The building’s elements can also be easily disassembled and reused for other purposes, a circular solution which further minimizes the climate impacts that occur when new material is sourced and used. Mass Timber construction also provides a basis for shifting from carbon-intensive construction methods to low-carbon ones. Promoting the use of wood resources grown using regenerative forestry techniques, with many benefits to watershed and biodiversity preservation as well as carbon capture, can further reinforce a positive circular environmental and economic feedback loop. In many parts of the world, this could provide the basis for significant new sustainable economic activity while meeting pressing infrastructure and housing needs.

Traditional Japanese buildings were constructed almost entirely from wood. Because construction methods did not rely on nails or adhesives, they could be easily repaired, reused, or dismantled for relocation. Because the dimensions of rooms and building materials were modularized, minimal processing or reassembly was required to reuse individual building components elsewhere.. In fact, the obvious reuse of old building material is an honored feature of the Japanese building aesthetic. 

During the pre-industrial Edo period in Japan (1603-1868), the protection and regeneration of forest resources was given a very high priority, which meant that wood was used carefully and great effort taken to prevent its waste. Large wooden beams and columns were in high demand, and there were lumberyards in large cities that specialized in this kind of used building lumber. Floor boards could be easily refurbished and reused, and doors and windows called shoji and fusuma were standardized in size and could be removed from one building and instantly used in another. The same was true of tatami floor mats, made of woven grass and straw. Roofing tiles could be easily resold and reused, and metal hardware and fittings such as copper downspouts and iron hinges were particularly valuable, because metal production required metal ore which was in limited supply, and also tremendous quantities of wood fuel, which needed to be preserved. There was almost nothing used in a traditional Japanese building at that time that did not have at least one good subsequent use, and even otherwise unusable clay wall plaster could be returned to the soil as if it has simply been borrowed from nature for a few years. All of the biologically-based materials, including wood, bamboo, paper, and rope, could be used as fuel or ultimately be returned to nature or the agricultural cycle, to decompose as mulch.

In recent years, a movement known as “Buildings as Material Banks (BAMB) has emerged which promotes exactly the kind of “building for reuse” that was practiced traditionally in Japan. The concept is to preserve and protect the material used in construction so it can be used again when the building is dismantled. From Japanese experience it is clear that excellent and beautiful building design can be made which is intended to minimize material use and to maximize reuse. When this is allowed to become the society-wide norm, it can significantly minimize the negative environmental impact of the building industry itself.

Designs developed by societies prior to the influence of Western industrial culture often exhibit what is known as “appropriate technology.” That is, technical solutions are kept as simple as possible, in tune with the environment, available resources, and the priorities of the society. In the case of pre-industrial Japan, every aspect of design was developed to a high degree of sophistication while remaining “appropriate.” A prime example is the use of natural cooling techniques for buildings, which was a priority due to Japan’s hot and humid summer climate. Houses and other buildings were sited in ways which made use of trees to provide shade to the entire building, and to help control wind. The buildings had very deep eaves, which provided enough shade to the outside walls to lower the internal temperature several degrees. Floors were raised off of the ground as well, creating a layer of cool air below which could help cool the interior. Sliding doors and window panels were used to control natural both light and air circulation.

Gardens were an essential part of this approach but in dense urban areas this was difficult for common people to obtain. Their densely-packed houses were usually designed with small gardens in back, shaded by neighboring buildings as well as trees, and quite a few had gardens in the center. These shady and moist tsuboniwa gardens, many of which still exist, are two-story pockets of cool greenery, and they form a microclimate that performs a critical environmental control function. They provide a continuous supply of naturally cooled air that is drawn through the rest of the house with the slightest breeze. The tsuboniwa gardens also link the living space on the second floor into the overall air circulation scheme, so that with the deft use of sliding doors and shutters it becomes a highly controllable bi-level cross-ventilation system. When multiplied by the tens of thousands citywide, the genius of this natural climate control system for high-density urban areas becomes apparent.

These design features can be usefully applied in places which have a hot, humid climate similar to Japan’s. But similarly appropriate natural design solutions have been developed over the course of centuries in virtually every region of the globe. Whether the environment is temperate, tropical, desert, or tundra, indigenous solutions are available to learn from.