Uncompleted Octagonal Void
Tainan, Taiwan, 2025
This is a restoration project of a modern church, originally completed in 1960 and designed by the German architect Gottfried Böhm. The first phase focuses on the restoration of the ceilings in two core areas of the sanctuary. Prior to this, we had completed the restoration of several smaller churches, experiences that shaped the way we perceive the coexistence of old and new. Our approach is guided by three principles: respecting the original design intent, responding to the progress of the times and new functional needs, and integrating the interfaces between past and future interventions. Between restoring the building according to its original design and introducing new measures for sustainable use, a certain misalignment inevitably emerges. It is precisely from these gaps that new meanings after restoration can overflow.
In 1951, Böhm visited the United States, where he came into contact with Ludwig Mies van der Rohe and Walter Gropius. This journey had a profound impact on the design of his own residence, completed in 1955. Situated on the riverside of Köln-Weiß, the house emphasized openness and fluidity of space, organized around a central courtyard. Rather than strictly adopting Mies’ minimalist language, Böhm combined massive load-bearing brick walls, steel framing, and large glass windows into a coherent whole. The courtyard floor was paved with red brick, and in the following years, expressive concrete sculptures and arched frames for climbing plants were added atop the flat roof. Several of his subsequent churches continued this design method: using load-bearing brick walls in tandem with framing systems to form horizontally flowing spaces, paired with conical towers—a spatial typology repeatedly appearing in this period. This church can be regarded as the first work in that series of experiments.
The floor plan follows a 60 cm modular grid system, with a structural span of 240 cm. Slender concrete columns with a cross-section of about 20 cm, together with 30 cm thick load-bearing walls, create horizontally ordered colonnades and the sanctuary. Three cones of different sizes and one square pyramid are placed at key positions, structuring the whole. The seating area belongs to the horizontal domain, with its ceiling integrating air conditioning and lighting to express the grid order. The altar area, in contrast, belongs to the vertical domain: its original octagonal pyramidal ceiling is restored to full height, integrating ventilation, lighting, and waterproofing, symbolizing the sacred and the mysterious.
The church’s exterior features an 18-meter-high square pyramidal tower clad in silver aluminum panels, creating a vertical sacred presence within the flat rural landscape. Inside the cone lies a 10-meter-high octagonal pyramidal space, directly above the altar—the sanctuary’s most sacred core. The gap between these two geometries produces an annular, functionless structural void. As part of the phased restoration plan, the octagonal pyramid required waterproofing. We concealed its wooden structure to eliminate visual distraction, allowing the abstract, pure, oversized silver geometry to confront the steel frame of the outer tower. This opposition reinforces both their relationship and their individual significance. A previously overlooked, functionless void was thus formalized as public and sacred—we call it the “new symbolic space.”
In early July 2025, on the eve of final inspection, Typhoon Danas devastated the Chianan Plain. The roof of the church’s main square pyramidal tower was severely damaged by strong winds, exposing the internal steel structure and the silver octagonal geometry, which now gleamed in the fields under the blazing sun of southern Taiwan. We added the words “Uncompleted” in front of the original name “Octagonal Void.”
這是一座現代教堂的修復計劃，原建築落成於1960年，為德國建築師Gottfried Böhm設計，第一階段計劃為聖堂兩個核心區域的天花修復。在此之前，我們已經陸續完成幾座規模不大的教堂的修復工作，它們影響我們如何看待新舊事物並存的關係。我們以三項原則為修復基礎：尊重原始設計意圖、回應時代進展與新使用需求、整合未來修建計劃新舊介面。在按照設計者原意恢復原貌與永續使用的新介入之間必然產生一種錯位關係，修復後產生的新意義將從這縫隙中溢出。
Böhm曾在1951年造訪美國，旅途中和Ludwig Mies van der Rohe及Walter Gropius有過接觸，這趟旅程的經驗深深影響了他於1955年完成的自宅設計。住宅位於Köln-Weiß的河畔旁，注重空間的開放與流動性，住居空間圍繞一中庭布局，他並未完全使用Mies的極簡主義語言，反而結合磚承重厚牆、鋼構框架與大面玻璃窗架構整體，中庭地面以紅磚鋪成，並於後續幾年內，陸續在水平屋頂局部增加表現性十足的混凝土雕塑與拱形框架供植物攀爬。其後數座新建教堂延續此設計手法，以承重磚牆搭配框架結構成為空間流動的水平性空間，和幾座錐塔並置成為這時期重複出現的空間型態，本教堂可說是這系列嘗試的最初作品。
平面遵循60公分模矩的網格系統，結構以跨距240公分，斷面約為20公分的混凝土細柱與30公分厚的承重牆構成水平性的柱廊空間與聖堂；三座大小形狀不一的圓錐與一座四方錐座落於幾個關鍵位置，架構起整體。座位區屬於水平性的空間，上方天花整合空調與照明，展現網格秩序；祭台區屬垂直性的空間，復原原正八角錐天花高度，整合通氣、照明與防水，象徵神聖與神秘。
外觀高十八公尺面覆銀色鋁板的正四角錐塔，在水平鄉野地景中產生垂直向上的神聖感，錐體內包覆一個高十公尺的正八角錐狀空間，它位於祭台正上方，為聖堂最核心的神聖空間，兩者夾擠出一個環狀無機能的結構空間。因應分期修復計劃，正八角錐體需具備防水功能，我們隱藏了正八角椎體的木結構，去除結構的視覺干擾，抽象純粹的超尺度銀色幾何體與錐塔內的鋼結構產生對立感受，強化兩者彼此關係與各自存在的意義，這個原本被忽略的無機能空間終被正式公共化與神聖化，我們稱之為「新象徵性空間」。
2025年七月初，工程驗收的前夕，丹娜絲颱風重創嘉南平原地區，聖堂主四角錐塔屋面受到強風嚴重的破壞，內部鋼結構與銀色八角幾何體完全裸露於田野之上，在南臺灣的烈日之下閃耀光芒，我們在原本的命名「八角虛空」（Octagonal Void）前面，加上了「未完成」三個字。
Location: Tainan, Taiwan
Program: Church
Design: 2024
Completion: 2025
Photo: Studio Millspace
業主 : 天主教台南教區
基地位置 : 臺灣臺南市
主要用途 : 教堂
設計時間 : 2024
完工時間 : 2025
攝影 : 揅空間工作室