Early in the history of Israel, God promised to lead his people through a pillar of cloud by day and a pillar of fire by night.  As a visual medium to signify his presence, yet one that was transitory, it could be said that the pillars of cloud and fire were the first biblical examples of ephemeral ecclesiastical architecture. The cloud and fire were certainly temporary; they indicated a designated meeting place between God and his people, and they exemplified architecture in its broadest sense—materials arranged for a specific meaning and purpose. Over time, other constructions became important to the Old Testament experience of the divine—altars, the tabernacle, and eventually the temple.
Fast-forward several thousand years and consider such nineteenth-century structures as revival tents or mail-order churches made of corrugated metal, which served ‘a shifting population swollen by itinerant workers who had no other access to formal worship and spiritual guidance’.  Societal upheavals, it will be noted later, often create a gap which ephemeral ecclesiastical architecture can fill in imaginative ways.
Embracing the idea of impermanence may teach the modern church about transcendence. There is no doubt that the grand cathedrals of Europe are architectural masterworks which have inspired those who enter them to worship or visit. But there is a definite earthbound nature inherent in massive stone edifices that—despite the appeal of a soaring Gothic arch or an expanse of brilliant stained glass—can invoke a vision of earthly—not heavenly—glory, of terrestrial permanence through sheer weight and size. Ephemeral ecclesiastical architecture approaches the idea of God meeting man in a completely different fashion. Its lightness hints at transcendence, and its temporality is indicative of the church’s emphasis on eternity.
Ephemerality synthesizes time, movement, and material. Robert Kronenburg observes of ephemeral moments that
it is almost automatic to assume that such fleeting experiences are relatively inconsequential. However, though they may be temporary in duration, their impact can be lasting. . . . It is therefore the power of the experience rather than its duration that is more important in gauging its meaning and effect. 
Movement is also key to understanding ephemerality. Richard Giles traces the development of ecclesiastical architecture from ancient sacred stones to today’s megachurches. He sees the dynamic nature of worship as a metaphor of a journey: ‘the primitive concept of holy place is given a new dynamic in the complementary concept of God journeying with his people to meet them wherever they come to rest’. 
As for materials, ephemeral architecture frequently ‘borrows from other non-architectural fields’, and its lighter footprint means that ‘proposed objects often seem suspended somewhere between the corporeal and the ethereal, the real and the virtual’. This transitory nature forms a ‘hybrid architecture, an architecture that acknowledges or provokes this emerging human condition of a being in a state of flux’.  Contemporary society is challenging and changing the notions of ownership, citizenship, and stewardship. Headlines about pop-up commerce, the sharing economy, disrupted business models, refugees, immigrants, displaced persons, sustainability, ecological design, and responsible building practices crowd newspapers, journals, and websites.
Three churches embody the ethos of ephemeral ecclesiastical architecture. One of the churches no longer stands, one has been disassembled and reassembled in a new location, and one is intended only as a place holder until its permanent replacement can be erected. Most interestingly, all three were built in response to dire need. The philosophical concerns of the architects and the resourceful methods used to build the churches serve as model methodologies for designing and constructing ephemeral ecclesiastical architecture.
Rainer Senn’s Chapel at St. André
‘This is what can be done in fifteen days with 60,000 francs, three men, and box springs as scaffolding. Provided, of course, one can find a master worker who feels right and is somewhat of a poet’.  Such was the glowing description of a primitive chapel (Fig. 1) built in 1955 by the Swiss architect Rainer Senn (1932-2016) for a community of ragpickers living at St. André, just outside Nice, France. The congregants were part of the Emmaus community, founded in Paris in 1949 by Abbé Pierre to help the homeless. The charitable organization still exists at St. André.
The square chapel, 12 meters on each side and topped with a pyramidical tarpaper-covered roof, was put together using rough-cut boards and without a poured-concrete foundation. Illumination came through a skylight and randomly placed gaps in the wall cladding.  One author has described how this construction allowed ‘a surprisingly solemn light to penetrate into the interior: shelter and temple in one’.  A photo of the chapel’s interior (Fig. 2) shows an altar made of unfinished boards and what appear to be cinder blocks, a semi-circular arrangement of mismatched chairs (probably cast-offs gathered by the members of the community), and a pattern of light beams stretching across the dirt floor. 
Senn, who was 23 at the time of the chapel’s construction—his first building project—writes how the design came about:
The person in charge, Pierre Tarteaut, explained in a few words how he conceived this chapel: a place where the community gathered to listen to the word of God. He did not envisage a longitudinal assembly, the lines one behind the other, but a community gathering around the priest who explains the word of God, as was the custom in the early days of Christianity. 
It is interesting to note that this arrangement of the congregation arose, according to Senn, from Tarteaut’s desire to unite in a symbolic circle the people ‘whom society had rejected’, and in this way restore them ‘to the protection of a community: of the Christian community’.  Indeed, Senn had to embrace the idea of community as his two assistants for the building project were untrained volunteers. The three used materials at hand and improvised as needed.
Senn had the advantage of working at a time of new horizons in architecture. In Europe, following the destruction that occurred during World War II, an opportunity emerged for rebuilding on a massive scale. Modernism was at its height, and no structure was immune from its design rationale, which prized minimalism and functionalism. Peter Hammond, in Liturgy and Architecture, describes Senn’s modest structure (along with some other contemporary examples) as having ‘an absolute truthfulness of artistic language, an extreme economy of means, and a high simplicity informed by a sense of liturgical function’, and he labels the chapel ‘one of the most completely successful symbolic structures of our time’ with ‘a poetry that springs from the purest sources of Christian tradition’. 
The profound paradox of the humble chapel designed to elevate the spirits of the oppressed remains its greatest achievement, a motif which reveals the potential of ephemeral ecclesiastical architecture. As an anonymous critic wrote soon after its construction, ‘In truth the means have little importance. What matters is the spirit in which they are used’.  Senn would likely agree; in 1961 he wrote that ‘poverty is a very fertile ground on which spiritual freedom can grow’.  This freedom is evident in architecture as well as human lives. Reflecting on the lasting significance of his buildings, Senn mused, ‘I would say this is more important than the individual buildings that have arisen. It is the human aspects that interest me’. 
This ethos of placing a greater focus on the people who would use it rather than the building itself prompted the author of Senn’s obituary to reflect that his ‘work as an architect was not designed for a great external effect. The purpose of his work was fulfilled in the everyday life of a community that could unfold in its rooms’.  Later in his life, when questioned about the significance of the chapel at St. André, Senn enthused, ‘It is the absolute key work!’  Though the chapel no longer stands, the simple but heartfelt approach which built it has appeared in the work of another notable architect.
Shigeru Ban’s Paper Church and Cardboard Cathedral
If Senn’s wooden chapel for the ragpickers was born from an economy of means for those in poverty, perhaps it can be said that Shigeru Ban’s paper churches are born from an abundance of technology for those impacted by crisis. The fundamental belief the two architects share, however, is their desire to design for society’s marginalized populations.
Ban’s innovative use of paper tubes appeared early in his career, in fact as a consequence of his first project, where he used screens of fabric to form partitions in a design exhibition. He explains, ‘The fabric was delivered on cylindrical paper tubes. I thought it was wasteful to throw the tubes away and took them back to my office in hopes of making use of them later on’.  It was a while, however, before the tubes could be employed as structural components with the approval of building officials, but once this was granted, Ban used the tubes to construct his Paper Church and Cardboard Cathedral, among many other projects.
One writer pinpoints the unique nature of Ban’s architecture:
In many ways, Ban’s thinking stems from the context of Japan, a place with a rich architectural history, a forgiving climate, contractors willing to take a chance, and an acceptance of physical ephemerality. Blending this knowledge with local conditions results in buildings characterized by clean-cut logic, environmental responsibility, and unbridled creativity. 
The Paper Church (Figs. 3 and 4) ‘is modelled roughly after Bernini’s wide, elliptical chapels’ . Built in 1995 in Kobe, Japan, after a massive earthquake left extensive damage to the city, the church became a symbol of hope to its congregants. The 58 paper tubes, 330 millimetres in diameter and 5 metres high, are arranged in various patterns, some close together and others
set more widely to facilitate the flow between the interior and exterior. Light enters through the PVC membrane used for the roof, and through the spaced paper columns. The interior can be closed off using 19 pairs of doors inset with polycarbonate panels set in a steel outer frame. 
The overall impression of the church is that of ‘a graceful presence’, one that gives ‘a feeling of grandeur even in such a modest construction’. Most importantly, as Ban says, ‘The experience in this small temporary building is in no way inferior to that in a large, magnificent cathedral’.  Later, Ban designed and built a permanent church in Kobe, and after 10 years, the Paper Church was disassembled and donated to a congregation in Taiwan which had lost its church in an earthquake.
The Cardboard Cathedral (Fig. 5) was built in 2013, also in response to an earthquake, this time in Christchurch, New Zealand in 2011. In addition to paper tubes, eight shipping containers form a base to support an A-frame roof and a colourful stained-glass window. Even the interior furnishings, like chairs and candle holders, are made of cardboard and wood.
Ban’s innovative mind is combined with a charitable heart. He believes ‘the way architects serve society, particularly minorities, may be an important factor in determining the character of this [21st century] era’. His humanitarian stance is evident not only in his designs, but also in the type of legacy he wants to leave behind: ‘I want to move people and to improve people’s lives. If I did not feel this way, it would be impossible to create meaningful architecture and to make a contribution to society at the same time’. 
In 2007, a chapel on wheels appeared in a nontraditional location—among the market stalls which pop up after football games in Lustenau, Austria. The wooden chapel ‘fits into a standard parking space . . . making it suitable for temporary stays at other locations also. Its gable roof in the form of an equilateral triangle symbolizes the Holy Trinity’. While many people in the twenty-first century might be baffled by the Christian belief that God ‘has pitched his tent among us’, seeing this chapel in a parking lot they would certainly understand the metaphor of God dwelling in the midst of his people. The diminutive sanctuary serves an evangelistic role as well: ‘For larger gatherings the side wings and the front can be opened by means of pneumatic springs to form a cross pattern, resulting in a covered outside area. The chapel then becomes the altar, while the stadium acts as the main body for the corresponding “church”’. 
Pope Francis has highlighted the fact that cities by their very nature call for a unique response from the church. He writes,
We need to look at our cities with a contemplative gaze, a gaze of faith which sees God dwelling in their homes, in their streets and squares. God’s presence accompanies the sincere efforts of individuals and groups to find encouragement and meaning in their lives. … This presence must not be contrived but found, uncovered. God does not hide himself from those who seek him with a sincere heart, even though they do so tentatively, in a vague and haphazard manner. 
Reflecting on the enormous cultural changes that occur in cities, he comments, ‘This challenges us to imagine innovative spaces and possibilities for prayer and communion which are more attractive and meaningful for city dwellers’, and he laments the fact that ‘what could be significant places of encounter and solidarity often become places of isolation and mutual distrust’.  The United Nations reports that 66 percent of the world’s population will live in urban areas by 2050,  so these concerns are not trivial, especially as increasing numbers of city-dwellers are migrants, displaced for political, economic, or religious reasons.
Like Pope Francis, Dan Hill stresses the importance of urban renewal, and his view of pop-up architecture is informed by notions of societal transformation. He writes, ‘At face value, pop-ups are not exactly a powerful agent for social or spatial change in the city’. Hill bases this belief on the inability of pop-up structures to influence building regulations and the fact that the structures are often ‘a parasitical form of organisation, best suited to inhabiting existing structures rather than creating new ones’.  However, he also believes that architecture can be part of
a clear relationship between the street, between co-opted spaces, with temporary structures, with communication technologies, with transient formations of communities of interest and propinquity, and with a wide variety of cultural activity inhabited by all of the above. 
In the current era, perhaps adopting attitudes informed by postmodern or post-Christian philosophies can lead to a more developed form of ephemeral ecclesiastical architecture. Weak architecture, related to Vattimo’s concept of weak thought, is ‘situational, contingent, elusive, and provisional’ as well as ‘reactive, dynamic, reflexive, and biomorphic, rather than mechano-morphic’. 
It is intriguing to align the terms used to describe this architecture with the values of the church—is it not meant to be situational, provisional, reactive, dynamic, and reflexive?
Ephemeral ecclesiastical architecture provides an imaginative and theologically inflected way for the church to meet the needs of diverse and fluctuating congregations, in addition to its economic and environmental sensitivity. The church is notorious for being a lugubrious institution, and while this cautious approach is consistent with its role as a guardian of eternal truths and immutable doctrines, it is often at odds with the ability to envisage new ways of ‘doing church’.
It is interesting to note how often religious vocabulary appears in writing about secular ephemeral structures. ‘They appear and disappear, because they adapt and inspire’.  The same should be said of the next generation of sacred structures.
 Exodus 13:21-22.
 Nick Thomson, Corrugated Iron Buildings (Oxford: Shire Publications, 2011), 2.
 Robert Kronenburg, ‘Ephemeral Architecture’, Architectural Design 68, no. 9-10 (1988), 7.
 Richard Giles, Re-Pitching the Tent: Re-Ordering the Church Building for Worship and Mission, revised edition (Norwich: Canterbury Press, 1997), 17.
 Nicholas Anastasopoulos, ‘Frontiers and Territories in the Architectural Discipline’, in Ephemeral Structures in the City of Athens. Book 2: Hermeneutics, ed. Maria Theodorou, Mark Cousins, Ole Bouman, and Lina Stergiou, Athens D.O.E.S. Series (Athens: Cultural Olympiad 2001-2004, 2003), 47, 48, 48.
 ‘Saint-Andre de Nice’, L’Art Sacré no. 5-6 (January-February 1957), 26.
 Rainer Senn, ‘Kapelle der Chiffonniers d’Emmaus in St-André de Nice’, Werk 43, no. 2 (1956), 34.
 Dorothee Huber, ‘Rainer Senn (1932-2016): Nachruf’, Werk, Bauen und Wohnen 103, no. 7/8 (2016), 58.
 Robert Maguire and Keith Murray, Modern Churches (London: Studio Vista, 1965), 104.
 Rainer Senn, in ‘Saint-André de Nice’, L’Art Sacré no. 5-6 (January-February 1957), 24.
 Peter Hammond, Liturgy and Architecture (London: Barrie and Rockliff, 1960), 158, 164.
 ‘Saint-André de Nice’, 26.
 Huber, 58.
 Reto Geiser and Martino Stierli, editors, Im Gespräch: 8 Positionen zur Schweizer Architektur (Basel: Standpunkte, 2015), 199.
 Huber, 58.
 Geiser and Stierli, 197.
 Shigeru Ban, ‘Introduction’, in Shigeru Ban, ed. Eugenia Bell (London: Laurence King, 2001), n.p.
 Naomi Pollock, ‘The Architecture of Shigeru Ban: Blurred Lines and Ambiguous Boundaries’, in Shigeru Ban: Humanitarian Architecture, ed. Mary Christian (Aspen: Aspen Art Museum, 2014), 32.
 Riichi Miyake, ‘The Birth of Paper Tube Architecture’, in Shigeru Ban: Paper in Architecture, Shigeru Ban, Riichi Miyake, Ian Luna, and Lauren A. Gould (New York: Rizzoli, 2009), 54.
 Phyllis Richardson, New Spiritual Architecture (New York: Abbeville, 2004), 202-203.
 Ibid., 203.
 Ban, in Bell, n.p.
 Christian Schittich, ed., Small Structures: Compact Dwellings, Temporary Structures, Room Modules (Basel: Birkhäuser, 2010), 108.
 Catholic Church and Francis. Apostolic Exhortation Evangelii Gaudium of the Holy Father Francis to the Bishops, Clergy, Consecrated Persons, and the Lay Faithful on the Proclamation of the Gospel in Today’s World (Rome: Libreria Editrice Vaticana, November 24, 2013), accessed July 27, 2017.
 ‘World’s population increasingly urban with more than half living in urban areas’, United Nations, http://www.un.org/en/development/desa/news/population/world-urbanization-prospects-2014.html, July 10, 2014, accessed June 8, 2017.
 Dan Hill, ‘A Sketchbook for the City to Come’, Architecture and Design 85, no. 3 (May 2015), 35.
 Ibid., 39.
 Enn Ots. Decoding Theoryspeak: An Illustrated Guide to Architectural Theory (London: Routledge, 2011), 209.
 Pilar Echavarria M., Portable Architecture and Unpredictable Surroundings (Barcelona: Structure, n.d.), 16.
Figure 1. Chapel at St. André. ‘Kirchenbauten von Rainer Senn, Basel’, Schweizerische Bauzeitung 77, no. 52 (December 24, 1959), 854.
Figure 2. Interior of chapel at St. André. Ibid.
Figure 3. Paper Church (Kobe, Japan). http://www.shigerubanarchitects.com/works/1995_paper-church/index.html.
Figure 4. Interior of Paper Church. Ibid.
Figure 5. Cardboard Cathedral. http://www.shigerubanarchitects.com/works/2013_cardboard-cathedral/index.html