In 2021, the United Nations Environment Programme stated that the buildings and construction sector accounted for 36% of the world’s final energy consumption and 37% of energy-related carbon dioxide emissions. Figures from the National Energy Administration at Taiwan’s Ministry of Economic Affairs tell much the same story. These shocking numbers suggest that we can no longer follow the existing “cradle to grave” model, in which materials are extracted, manufactured, and then routed into consumer waste, and should instead plan from the earliest stages of product design to reuse resources or to break them down into “nutrients.”

The renovation of former official residences of Japanese military officers is giving new life to old wood, tile and glass. The passage of time has imbued these materials with a texture and patina that new materials can’t match.

Starting with materials

Taiwan is keeping pace with the international community in this area. Our first materials bank, the Tainan City Cultural Heritage Architectural Materials Vault (HAMV), was established at the Soulangh Cultural Park in Tainan’s Jiali District in 2017. HAMV collects old materials from all over Taiwan, enters them into a database, and supplies them to builders and renovators who need them. HAMV puts the concepts of circularity and sustainability into practice by ensuring that every brick, beam and tile gains new life in another building.

Chen Cheng-che, who heads the HAMV program, explains, “We are making materials ‘circular.’” While the concept is simple enough, it can be hard to put into practice. “Making old buildings and old materials circular is a really big challenge.”

First, where do you obtain old materials? Second, how do you extract these materials intact, and establish standardized procedures for coding the various items? Third, how do you get old materials to those who can use them? “You have to link all of this up to create circularity,” says Chen.

HAMV has received donations from all kinds of places, including public-sector entities such as the Tainan Judicial Museum, local government offices and school dormitories, as well as from private sources such as sanheyuan (traditional courtyard homes) and other homes undergoing renovations. It once even got a large amount of glass from a building supply company that was going out of business.

A lot of work goes into obtaining reusable building materials, and the process requires constant ­communication. For example, when the team learns that an old building is going to be torn down, it rushes to the site to inspect the structural timbers, and prioritizes collecting materials that can be reused, such as wooden flooring, doors, windows and roof tiles. Once heavy demolition equipment enters the site, the team befriends the workers by bringing them water and betel nuts, and then works with the backhoe drivers to suggest paths and angles of approach to the demolition in ­order to keep the reusable materials as intact as possible. Whatever the team salvages then has to be transported, cleaned, separated, organized and cataloged. The final step is bringing more people into the sustainability circle by making the community aware that materials are available and matching them with users.

The Tainan City Cultural Heritage Architectural Materials Vault collects every reusable brick, tile and piece of wood that donors provide, turning them into “nutrients” that will be reborn into a new life.

Reuse, not preservation

Chen gives us a tour of HAMV’s warehouse and tells us about the various materials. “We can take pretty much any building material from a structure, but wooden items have the highest level of reusability.” Outside, we see old China fir, Taiwan incense cedar, false cypress, and longan wood, all of which can be put to use as replacement structural members in future renovations. We also spy aluminum-alloy frames acquired from Taipei’s Songshan Tobacco Factory and dating from the US aid period, and onigawara (ogre-faced roof ornaments) of various sizes made by different manufacturers, all of which will be sorted before being sent out for reuse.

“Circular reuse like this also fixes carbon,” says Chen, linking HAMV’s approach to a hot topic. He explains that HAMV can calculate the amount of carbon fixed in wooden materials based on their volume, enabling the organization to calculate how much carbon its work fixes, and potentially winning it a carbon neutral designation.

The bank has previously had people donate secondhand furniture in hopes of preserving it, but Chen says, “The bank’s objective isn’t preservation, it is reuse. Once items come into the bank, they are broken down into materials that can be reused.” People wishing to use these materials for heritage sites, old buildings, social welfare projects or artworks can all request them free of charge.

“The goal of recycling materials is circularity,” says Chen. “You don’t recycle to save money, you do it to improve the environment. Plus, good-quality old materials improve the quality of buildings.” The team therefore has frequent conversations with designers, building firms and craftspeople in its efforts to persuade architects and builders to incorporate secondhand materials into their plans and projects.

Chen takes us to see a number of former official residences for Japanese military officers in Tainan’s North District that are now undergoing renovation. The restoration team has used a variety of old materials from HAMV, ranging from wood and onigawara to glass and fasteners, to renovate the clapboard siding, doorways, roofs, catwalk flooring, traditional Japanese windows, and balcony railings. Chen Zhixian, a member of the construction team, says that reusing old materials tests their skills on the jobsite and requires a lot more work. “But reusing materials in an old building has its own significance and value, and gives us a real sense of achievement.”

Chen Cheng-che says that every item at HAMV has a history and a story.

Making materials part of the circular economy requires the HAMV team to spend significant time communicating, networking and matchmaking. (courtesy of HAMV)

The crafts of the past

Old building materials have already adapted to Taiwan’s climate. Stable, weathered down to their essence by the passage of time, they have a texture and patina that new materials can’t match.

Old building materials are also a kind of historical record, preserving construction data and technologies from the time of their first use, embodying the stories of their era. Chen Cheng-che points to an ox-eye window taken from the Tainan Judicial Museum. It is too large to have been crafted from a single piece of wood, and when we look closely, we can see that its round form consists of four pieces joined by rivets. The window is also sheathed in a layer of copper to protect it from the rain. Since ox-eye windows are no longer ­produced in this way, this one provides us with a tangible example of the carpentry and craftwork techniques used in the day.

In addition, secondhand materials are often marked with the name of the company that produced or imported them, which can be informative for those involved in restoration work. Extant materials can also provide an understanding of frequently seen techniques like mortise-and-tenon or rattan-bound joints between beams and columns.

All the materials stored at HAMV are awaiting their chance to be matched with a new user.

Recycled materials have contributed to the renewal of any number of buildings. The photo shows the Needed Bookstore at the Shueijiaoshe Culture Park in Tainan’s East District.

The Yichang Rice Mill in Tainan’s Houbi District “inherited” materials from a rice mill in Madou District, as well as some of the fond feelings attached to the latter.

Stories of reuse

Shortly after HAMV was founded, Longgang Primary School in Tainan’s South District let it know that it was going to tear down a Japanese-era school faculty residence and donate the materials to HAMV. When renovators working on an old home in Yanshui District requested materials, the HAMV team strove to provide wood donated by the school for use as the home’s trusses. “It was as if the old Yanshui home inherited a big gift from the Japanese-­era residence,” says Chen.

Chen then tells us another story of passing on a material legacy, this time involving two rice mills. When the Hexing Rice Mill in Tainan’s Madou District became obsolete, its owners, the Chen sisters, decided to donate the mill materials to HAMV. The HAMV team carried out a historical inspection, surveyed the site, and built a 3D computer model of the mill before matchmaking the materials with the Yichang Rice Mill, then undergoing renovation, in the Jingliao neighborhood of Tainan’s Houbi District. The Hexing Mill’s beams, columns, doors, windows and mechanical components all contributed to the rebirth of Jing­liao’s rice mill. Chen Cheng-che says that the five Chen sisters occasionally get together to visit Jing­liao the way they might visit their parents’ home. “Our work doesn’t just facilitate the sustainable reuse of materials. It also sustains people’s feelings.”

Over the five-plus years since the founding of the materials bank program, it has contributed materials to more restorations than it can count, including those of the Shen clan ancestral hall in Baihe, a lecture hall at the old Tainan Presbyterian Middle School, the San­chuan Hall of the Zonggan Temple, the Needed Bookstore at the Shueijiaoshe Culture Park, the Old Julius Mannich Merchant House, and a Japanese-era residence for officials of the Tainan Prefecture ­admin­istration.

As the sun sinks low in the sky, we snap a photo of the HAMV team in the yard where they work so hard sorting materials, and we gaze at the fruits of the labor, the items quietly awaiting their perfect match, looking forward to embarking on a fantastic voyage that will see them once again become part of a building.

An artist’s use of discarded window grilles to create an installation demonstrates another application for secondhand building materials.

The team at HAMV is working to build a sustainable future.