JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING 2021, VOL. 20, NO. 1, 1–11 https://doi.org/10.1080/13467581.2020.1782208 ARCHITECTURAL PLANNING AND DESIGN “Internal envelope”, a practical exploration of contemporary interior space regenerated in traditional buildings Li Guo and Chen Zhao Department of Architecture, School of Architecture and Urban Planning, Nanjing University, Nanjing, China ABSTRACT ARTICLE HISTORY Received 24 August 2019 Reviving historical towns and urban districts requires conservation and reuse of traditional Accepted 29 May 2020 buildings crucially in preserving the external form while introducing contemporary contents into the interior spaces. Short of contemporary comfort and efficiency, the traditional interior KEYWORDS unavoidably contradicts the preservation for according improvement of comfort as the crux. “Internal envelope”; Setting out from construction rule and characteristics of the traditional Chinese architecture traditional buildings; with reference to its European counterpart’s “envelope” feature, we propose “internal envel- adaptive reuse; interior ope” as a new interior implanted into the traditional interior, a freestanding container of self- comfort; regenerate bearing framework of up-to-date techniques that accommodates all needs from office, resi- dence to recreation. In ensuing practices, the “internal envelope” successively applied in a series of cases in the historical town of Cicheng, Ningbo, and each case designed in response to specific structure and scale of the courtyard and interior to ensure the desired comfort. As the representative one, Cihu Academy attested “internal envelope” thorough and successful realization from conception, scheme, construction to put into service, a full course that demonstrated its validity in its own right as well as significance to architecture the discipline in sound response to targeted problems. 1. The adaptive reuse issue of traditional to be adaptive reuse (hereafter referred as reuse) of buildings in historical towns and urban districts the traditional buildings of conservational values in a reasonable and effective way. It is also reflected in the In revival work of existing historical towns and urban content programming engaged with historical town districts, the most often confronted problem turns out revival, which demands in such terms from researches CONTACT Li Guo firstname.lastname@example.org Department of Architecture, School of Architecture and Urban Planning, Nanjing University, Nanjing, China “Adaptive Reuse is defined as the aesthetic process that adapts buildings for new uses while retaining their historic features. Using an adaptive reuse model can prolong a building’s life, from cradle-to-grave, by retaining all or most of the building system, including the structure, the shell and even the interior materials. This type of revitalization is not restricted to buildings of historic significance and can be a strategy adopted in case of obsolete buildings.” According to Chaoching Fu, “Western scholars and construction professionals use the same words to describe reuse. The most common words are © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the Architectural Institute of Japan, Architectural Institute of Korea and Architectural Society of China. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 2 L. GUO AND C. ZHAO in urban and architectural design. Especially, when it construction or simply restoration, difficult in dealing comes to buildings in historical districts of fabric con- with various “mismatches” between traditional build- servation in a large scale, the revival work of historical ings and contemporary needs. Thus, transformation of towns as a whole is directly determined as a success or “mismatches” into “matches” signifies the regenerating failure. operation of interior spaces in traditional buildings, Within the realm of historical building and cul- which not only falls on the architect’s shoulder but tural heritage conservation, it is restoration around also bears significance to architecture the discipline. particular/single historical buildings that sees rela- The traditional Chinese architecture features a tively better developed theories and practice. unique, systematic structure as well as construction Especially for those graded and prescribed by the logic, which continually developed into complete protection regulations of cultural relics, the content mature ways either brick-timber or earth-timber con- and function of reuse after repair/restoration are struction systems, the independent timber framework restricted strictly, mostly in museum or exhibition, comprising main components from column, beam, leading to tight and clear guidelines to follow for lintel to purlin and envelopes including wall and related design methods and technique application. roof. Therefore, taken under the contemporary stan- However, so far as the revival work is concerned, the dards, there are limits to the interior space due to its historical towns and districts shall be infused with own construction rules and spatial traits, “mismatch- various programming so as to become the container ing” in many aspects: (1) restricted height and span; (2) and place for contemporary urban life and produc- low openness; and (3) inferior thermal engineering tion no longer isolate entities. Such introduction effect, meagre lighting and weak sound insulation of from office, education to retailing, featuring in living the whole building envelope including wall, partition, if possible, namely residential and hotel, could on floor, lobby and roof in traditional construction. All in the one hand fully vitalize each single building up to all, the “mismatching phenomena” of traditional build- a whole district with continuity of time and patina of ings could be categorized into two, the interior space history and on the other demand higher from the and the interior environmental comfort. reuse ways in both design methods and technique Its effects as an important prerequisite for reuse of application than befitting the cultural relics, which traditional buildings that no unaffordable functions are necessitates breakthrough and expansion in particu- imposed upon and compatible use are conferred. lar technique and practice. Therefore, the regenera- Throughout the reuse, introduced contents such as tion of contemporary interior spaces in traditional office, studio, auditorium, meeting and dining could buildings owes its explorative practice to the need accordingly lead to exploitation of interior spatial for reuse and contributes to the revival of historical potential, reorganization of spatial layout and circula- towns/environment. tion and even removal of non-bearing partitions so as to accommodate the up-to-date criteria with a more open space. Though too familiar the skills are for archi- 1.1. Problems with traditional buildings for tects, it still poses a question as how to improve the modern interior space interior environmental comfort to meet contemporary needs, with the precondition fulfilled of main original Reuse of traditional buildings means conversion of the structural components under duly protection. Many existing usage or idle state, with the interior space cases of reuse seem neither watchful nor mindful of focused upon for the potential to exploit to transform the “mismatching” performances, copying notions of into a new life. Hence, it essentially differs from new renovation, rehabilitation, remodelling, recycling, retrofitting, environmental retrieval and extended use, reborn, adaptive reuse, etc. Among them, adaptive reuse seems the best way to express the concept of new use for old houses, also often referred to as reuse” (Chaoching Fu, “Institute of Architecture”). Yukio Nishimura, Translated by Huijun Wang, “Nourished on sanguinity and vigour of the effulgent era, the historical edification could well rely on reuse measures to pass each generation of owner’s emotion and effort input onto the next. Speeches and comic talk shows held in the stone warehouses and other historical buildings could count as a transcending conservation over the long-observed specimen-box mode and a concrete ‘new conservation manner’ practising the ‘historical building revival & reuse’, which proposed not only ‘displaying for the visitors’, but also ‘lively sight-seeing bustling with life’ . . . ” (Nishimura and Wang 2007, 37). Chaoching Fu, “Institute of Architecture.” Amos Rapoport, “My basic hypothesis, then, is that house form is not simply the result of physical forces or any single causal factor, but is the consequence of a whole range of socio-cultural factors seen in their broadest terms. Form is in turn modified by climatic conditions (the physical environment which makes some things impossible and encourages others) and by methods of construction, materials available, and the technology (the tools for achieving the desired environment), I will call the socio-cultural forces primary, and the others secondary or modifying” (Rapoport 1969, 46).: China Architecture Design & Research Group, Architecture History Graduate School, “It is an illustrative example of ‘Only fallen walls, no failed house’, an old saying that lauds the traditional Chinese architecture for the timber framework freestanding from the sheerly enveloping or partitioning walls, which greatly liberates material choices, fenestration, openness and enclosure, fitment and dissembling, partition and alteration, namely the layout and zoning” (China Architecture Design & Research Group, Architecture History Graduate School 2007, 163). Ulrich Knaack, Eddie Koenders, “The building envelope is the barrier between the interior and the exterior – the place where the energy flow is interrupted or deflected. Accordingly, the building envelope exercises a direct and significant influence on the interior space and its functionality as well as on the energy balance of the building” (Knaack and Koenders 2018, 11). Australia ICOMOS Incorporated International Council on Monuments and Sites, “1.11 Compatible use means a use which respects the cultural significance of a place. Such a use involves no, or minimal, impact on cultural significance” (The Australia ICOMOS Charter for Places of Cultural Significance 1999). JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING 3 redecoration or interior design and exercising sus- 1.2. Contradictions between conservation and pended ceiling, fixed air-conditioner, lighting and sani- reuse of traditional buildings tary fittings that inevitably impair existing There exist essential differences ranging from ideol- components, thus confusing the old with the new in ogy, terra, climate, construction and even technique one and the same way or even adding a final antique in between traditional Chinese architecture and its finish, highly intervening and irreversible, let alone the western counterpart. While the international charts ineligibility as exploration or exemplar. However, those and related discourses concern more with meaning aware of keeping the original envelope intact and and principle, barely operable for the Chinese sector improving the interior comfort cannot avoid high featuring brick-timber, whereas thanks to continuous energy consumption for the former’s poor thermal criticism and revision, the latest theories begin to insulation. transcend the general ethics on physical preservation So the real challenge lies in the effective improve- and replace it with a multi-purposed benefit optimiza- ment of interior comfort in traditional buildings. As tion, with the user’s need and expectation well time advances, both the lifestyle and modern facilities supported. in continuous updation and configuration could not Either as physical constituent to the urban fabric or follow the past behaviour. Contemporary contents and for the historic-cultural values as well as aesthetic sig- functions need a range of corresponding interior com- nificance innate, the traditional building demands so fort in thermal, illumination, acoustics, electrics and much as it deserves an intact dual presence of the sanitation, among which the thermal comfort ranks exterior and interior for social significance as well. as the utmost necessary yet intractable for improve- Taking the ambulatory Zoumalou and residence ment, namely heat preservation. The very absence of Baoshantang in Cicheng, respectively, renovated into hermeticity typical of modern architecture is due to the dining hall and tea- and meeting-room for example, envelope’s construction condition and definition role, the popularity attested the well-kept historical taste in meant mainly to differentiate the interior from the both layout and imagery that satisfied preservation exterior, taking the southern vernacular brick-timber and exhibition criteria, while the reuse strategy did structure, for example: the lightweight wall is both fail to reinforce thermal insulation as targeted against hollow in masonry and shallow in foundation; the energy consumption in heating and refrigeration, let floor paved with slates or bricks; the roof covered alone basic needs in lighting and sound insulation. with sheathing bricks and then blue roofing tiles; the And such cases are actually ubiquitous in all regions inward interfaces often seen as thin or even pattern- represented by Cicheng, doubtlessly suffering in revi- perforated panels; most joints in between too loose for val from interior discomfort and contradictions ventilation against moisture. Moreover, the few and between conservation and reuse. slight openings are mostly inward facing the courtyard, To keep the original envelope intact for historic and meagre in lighting, while the upper floors poor in artistic display, a new envelope may be implanted to sound insulation too. accommodate modern life and work without contra- Therefore, what a renovation could fit the existing dicting the existing openings and interfaces. Pay to envelope of traditional buildings to contemporary History what belongs to History – and Present what needs in life and work? Direct and tactless alteration belongs to Present, that is what we propose to tell one upon the original structure and envelope usually, out of the other in form and material for aesthetic respectively, end up in damage due to the overweight effect, like Carlo Scarpa’s legibility as imprint of time of equipment or perforation for pipeline and excessive through joineries of his old and new. Comprising a cost in addition to materials with no increase in insula- freestanding structure, the components directly inter- tion performance. What is more, lighting often calls for vene and alter the existing major ones such as column, more opening, to which again the envelopes involved beam, truss, wall and roof to such low extent that it in trouble, not to mention suspended ceiling that well fits in the minimum intervention principle advo- again puts the structure at stake, though moderately. cated in theory; meanwhile, the very materials chosen Witnessing the addition to and refurbishment on the among wood, bamboo and polycarbonate are all body prone to irreversible damages with hardly plea- reversible, accommodating likely changes in the sant effect, could we seek new possibilities for a pack- future. In the long run, all contemporary content and age solution to the interior environment? That is function are literally temporal when compared with rightly this research’s gist. Salvador Munoz-Vinas, “Contemporary ethics offers better answers than classical theories, but this does not mean that these are easy answers-quite the contrary. Contemporary theory says to anyone involved in conservation decision-making that things are not as easy as classical theories suggest: decision-making does not consist of deciding how to implement a number of well-known directives. Decision-makers are not just limited to studying how to enforce truth within the object. Contemporary ethics asks them to consider the different meanings that an object has for different groups of people, and to decide not just which meanings should prevail, but also how to combine them to satisfy as many views as possible” (Munoz-Vinas 2004, 213–214). 4 L. GUO AND C. ZHAO the historical, therefore demanding a prudent altitudes typical of European construction, which natu- attitude. rally leads to a high demand on airtightness against heat All in all, started from a clarification of the issue, the loss and moisture penetration in frigid weather. The tradi- research is committed to package-solved the interior tional European wooden architecture has developed a full comfort problems for contemporary life and work so as play of construction measures to reinforce airtightness in to achieve a sustainable and benefit-optimizing status the wall and roof. In the log buildings, an accurately fitted of conservation and reuse, which truly revives the kinning was decisive in sealing the joint. Between the traditional building. logs, grooves are packed with strong water-absorptive moss; atop the roof, curved shingles are produced in order to create a dense, enclosing envelope; the turf 2. Conception and background of “internal roof also features traditional insulation layer of birch envelope” 14 barks beneath the sods of grass on the roof. With the structure discharging internal dampness while impregna- In light of the discussion above, the authors set out to ble to the external moisture, heat preservation is well borrow envelope, the western term, based on full cog- ensured without compromising breathability. So does it nition of the Chinese counterpart, and propose internal in the contemporary as a guarantee for interior comfort, envelope, a conception creative in implanting a new with good physical properties consisting of the building interior featuring envelope into the traditional interior. envelope. Depending on the materials, construction and Thus, paralleled with contemporary needs for interior joints used, energy flows and humidity transport are comfort, it signifies a confluence of western architec- inhibited, limited or enabled, if so desired. Good insulat- tural terminology with Chinese reuse practice. ing properties allow keeping heat inside the building in winter and excluding it in summer. 2.1. Envelope as an architectural term In the western context, envelope usually refers to the 2.2. Proposal of “internal envelope” as a new skin of a building, or particularly the building envelope concept that barriers the interior from the exterior as we know and use, highlighting its wrapping role. It might date By contrast, as above-mentioned, traditional southern back to Gottfried Semper who theorized the skin fea- Chinese architecture has its outer envelope thin and less 10 15 turing fabric-coated walls as “dressing” and Adolf hermetic in joints as local climate allows, therefore see- Loos who emphasized the wall cladding’s key role in ing little such wrapping feature. It is not only due to local spatial enclosure in his theory of cladding as clothing, climate demanding more damp-proof and ventilation until Le Corbusier defined surface as “envelope” of the against summer heat and humidity but also owing to a mass that can “diminish or enlarge the sensation the wintry clothing habit that hardly exacts warmth from the latter gives us” in his Vers une architecture, which her- light timber framework. However, neither wintry burden- alded modern architecture, gradually distinguished some clothing nor summery fitful coolness seems able to envelope from the classic façade as surface, skin ensure an enduring comfort in both temperature and did. It is also noteworthy that Bernard Tschumi inter- humidity. preted envelope more from the perspective of social Therefore, it becomes most necessary and natural to context in his “Vectors and Envelopes”, followed by Greg re-devise a wrapping envelope meeting contemporary Lynn stating “Form can be shaped by the collaboration needs and functioning in thermal insulation that befits between an envelope and the active context in which it the interior environment, once the external ensemble is situated.” In this way, the abstractness and auton- of a traditional building has given way to its historic omy developed by envelope function as a reaction and values justifying conservation. In the case of being means of architecture in responding to current urban confused with the envelope usually external, a qualifier complexity and emerging societal needs that lead to is proposed, drawing out the new term “internal envel- new spatial cognition and form expression. ope” (Figure 1). Re-devised this way, it both respects The emphasis of envelope on wrapping could easily the existing interior spaces without transgression and find its explanation from the higher latitudes and also untangles the serial mismatching listed above up Salvador Munoz-Vinas, “Sustainability in conservation is similar to reversibility or minimum intervention, although it is a more complete notion as it more explicitly acknowledges the need to take future uses and users into account” (Munoz-Vinas 2004, 196). Kennth Frampton, “The empirical fact of this primordial shelter prompted Semper to propose an anthropological counter thesis to Laugier’s primitive hut of 1753. In its place, he proposed a more articulated model comprising (1) a hearth, (2) an earthwork (3) a framework/roof, and (4) an enclosing membrane. . . . . . . Thus, while he regarded clay as the primary moulding material or Urstoff , this did not prevent him from seeing facing brick or tile as a ‘dressing,’ a kind of petrified fabric and hence a transformation of nomadic textile forms into a more permanent material” Frampton (1996, 85–87). Leatherbarrow and Mostafavi (2005). Lynn (1999, 9). Zwerger (2011, 143). Oliver (2006, 40–41). Li (2015, 152–161). JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING 5 Figure 1. Conceptual diagram of “internal envelope” (drawn by the authors, March 2015). to a complete satisfaction, hence establishing a clear 3.1. Definition of the spatial scale old–new order for the historical interior, highlighting Restricted in the spatial organization and construction an incorporation of western architectural concept into rule typical of traditional buildings, the internal envelope Chinese reuse practice of traditional architecture. has its scale determined by number and scale of bays as well as the structural-spacing relationships between the beam and column. First of all, taking a three-bay porched 3. Strategy and features of “internal envelope” single building, for example (Figure 2), structurally it is in generating traditional interior spaces composed of four paralleled trusses, each of them linked The “internal envelope” strategy follows such princi- to its neighbour by longitudinal (along the frontage) ples: within the traditional interior, leaving the existing components, namely purlin and lintel. For an average components (beam, column, purlin, lintel and rafter) chuandou (penetrating and interlocking) structure, and envelope alone while employing ecological, light- every column in a truss shall end at the end, namely weight and good-thermal-performance materials to down upon the ground, only with partial exceptions construct freestanding and self-bearing frameworks where lifting-beam ways truncated the column between freestanding from the former interior interfaces. And the beams, which frees up the projections and enlarging the “internal envelope” generally unfolds from the the spacing across two steps or more. Generally, each bay aspects as below. spans over 3–4 m, while the depth is counted by the Figure 2. Prototypical diagramming of the “internal envelope” in a bay (left), a three-bay porched single building (right) (drawn by the authors, June 2014). Qinghua Guo, “‘chuandou’, post-and-tie construction: A type of building structure with purlins resting directly on posts, and with tie beams tying the posts together in the tranversverse directions; an archetype of the tingtang 1” (Guo 2002, 25). 6 L. GUO AND C. ZHAO bujia (steps), namely, the spaced columns that lift a taken into the envelope top as strip lighting, integrated truss, usually numbering from 4 to more than 10 by the into the envelope panel together with weak current spacing between 1 m to one and a half; below the roof, it facility and placed atop as vacuum reducer valve (VRV) is up to the level of horizontal components that counts as in accordance with interior air supply system. valid height, while beyond that, the triangular-sectioned In general, the “internal envelope” has advantages space barely meets any use and challenges heat insula- as follows: tion, which dictates an appropriate height range of the internal envelope between 2.5 and 3 m, well fitting (1) Freestanding framework, separated from the ergonomics. structural systems of the traditional buildings; (2) Reversible construction; (3) Easily operable dry-assembled construction with 3.2. Framing few wet operation and welding points; The framing of an internal envelope is based upon the (4) An integrated “shell” equipped with all devices column spacing, or step relationships within a truss finalized to the generation and maintenance of typical of the traditional building, as shown in Figure the thermal, acoustic and luminous comfort. 2. Takes a bay as a prototype, the vertical components are stepped back at both sides from each existing 4. Practical case of “internal envelope” column center by an interval of 180 mm, namely, the strategy in Cicheng traditional interiors maximum radius of the plinth. So, each step divides into two, 360 mm and the rest, which makes up the From 2006 to 2015, our atelier conducted practices internal envelope’s framing series. While it is bolt joints in Cicheng Town, Ningbo City, Zhejiang Province, that fix the vertical component to the cross and long- aimed at regeneration ways of interior spaces so as itudinal ones, among which the former, the cross ones, to revive the traditional town and environment. i.e. along the depth of the building, take the lap joint Cicheng Town, actually the Cixi County for over way to reinforce the freestanding framework. When it 1300 years, is overall integral and intact with rich comes to the materials, it needs overall consideration remains, which received ample restoration since that decides on lightweight and easily dealt and fixable development launched in 2002, and won the ones for structure, and again the strength criteria and UNESCO Honorable Mentioned in 2009. construction convenience further restrict the choices Once conserved and revived the old town of in rotary-cutting laminate and pinewood. In the light of Cicheng should keep the traditional configuration the span between 3 and 4 m, the vertical section is and environment while meet up-to-date urban determined at 90 × 90 mm, while the horizontal needs . . . The balance point being sought in 90 × 45 mm and 90 × 30 mm. between history and reality finds itself in how the old town locates its function in the developed future of a new Cicheng. With the latter taking on living 3.3. Envelope system and leisure and within the whole picture of Greater Ningbo, it naturally falls on the former for sightsee- In choosing the enveloping panels, the criterion proves ing, recreation and resort. The very significance to be lightweight and effective performance in heat raises a question as how to reinvigorate it with a insulation, especially for high summer and winter. urban clamour and glamour instead of dry and dull ‘curios’ for tourists, which demands us to present, Therefore, like wooden panels of high strength and besides what it is now as an old town welcoming lightweight, hollow polycarbonate sheet is also recom- sightseers for pleasure or leisure, a urbanism in time- mendable in vertical interfaces, especially for its light honored unique use in its own right. transmittance ranging from 10% up to 80%, ensuring lighting so well to be often dubbed as sunshine panels Therefore, it awaits resolution as how to take due use in China. Generally, the internal envelope has its open- of them and, if possible, introduce multiple program- ings, namely, doors and windows fitted into the exist- ming and functions matching the revival of Cicheng, ing ones, the sliding way of opening is chosen to save which in the end calls for an exemplar to reconcile the spaces from pulling and pushing radius. contradiction between modern working and living requirements and the traditional building. Between 2007 and 2015, we applied the internal 3.4. Equipment envelope strategy in several traditional building cases as As an incorporated carrier, the internal envelope is below: (1) Confucius Temple Studio, 2006–2007, on the obliged to solve modern facilities including lighting, western lateral courtyard of the County Confucius electrics and air conditioning, which are, respectively, Temple, intended to regenerate appropriate interior Qinghua Guo, “‘bujia’, A unit referring to building depth called bujia in Qing architecture, e.g. 4-rafter building; maximun, 12 rafters” (Guo 2002, 25). Zhao, Yan, and Duan (2006, 53–55). JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING 7 spaces where the relic-labelled buildings were devoid of The former Cihu Academy was first founded by significance for display and idle from particular use; (2) scholar Jian Yang in the Southern Song Dynasty (exactly Cihu Academy, 2013–2014, founded by a group of 1225–27) ashore Cihu Lake, the town’s back lake, and renowned scholars, to whose requirement on seminar nurtured literati ever since. On the eve of the Republic and lounge rooms we successfully implemented the from the Qing Dynasty, it is restructured and renamed internal envelope to highly acclaim; and (3) No. 67 Rd. into Cihu Middle School, lasting till this day. The Cihu Taihu Studio, 2015, where the top of the envelope was Academy, founded anew by a group of influential intel- experimented for ventilation optimization and the inter- lectuals, is a further education and training base of ior comfort promoted. Varying in size, scale and structural sociology. Located in the Taihu Road historical district type typically of traditional buildings, each case met a adjacent to Cihu Lake, it is replenishing the area with 2 2 readily adapted envelope in layout and framework. cultural vitality. It covers an area of 882 m , built 533 m . Featuring and functioning as an advanced seminary and forum of humanities, it would enliven and enhance the 4.1. Research and exploration fundaments of whole district’s cultural atmosphere and taste. “internal envelope” in Cicheng Confucius Temple It comprises five rows of buildings with four court- Studio, 2007 yards in between, among which the main building is five-bayed in frontage, two-floored and timber-struc- Situated in the north-western corner of The Confucius tured. It is expected of a meeting hall of 70 people, Temple, Cicheng, now registered as a Key Cultural Relics office and seminar for 8–15, two tatami-styled lounges Site Under the State Protection, the studio is relatively for teachers aside from middle hall, reception, kitchen, independent, comprising 3 three-bay buildings sequen- dining and sanitary facilities. In laying out the functions tially, forming two courtyards in between, formerly used and combing the circulation properly, one finds the as subsidiary rooms for the grand temple. Quite unitary in seminar room placed on the ground floor of the main content and function, the internal envelope inserted this building, the pair of teachers’ lounges separated from time is meant right for office or meeting, fully respecting each other by the middle stairs and communal space the existing layout while satisfying present requirements. on the upper floor. Based on an analysis of the user’s Though all taking up one single floor, the three each has behavior and activity pattern, the “internal envelope” is a variation of internal envelope: for Building A, all three applied in more frequented and heat-preservation- bays are internal-enveloped into one whole interior, demanded spaces, namely the seminar room and enabled by lifting-beam and eliminating-column ways lounges (Figures 3 and 4). to emerge and amplify the spaces suitable for an office; for Buildings B and C, the middle bay is excluded while both the end ones are internal-enveloped, only differing 4.2.2. Structural solution of “internal envelope” at the door for opening ways, the former serving as The seminar is placed in two existing connected bays circulation area connecting the front and back courtyards sized 7.8 m × 8.6 m together. The middle row of and also accommodating public activities. First experi- columns is both without partition wall and freed uni- mented on a case of grouped buildings, namely, the formly along with others in the general beam-lifting Confucius Temple Studio, the internal envelope was way. So the column spacing merges two steps into tested in a general structure of three bays and, by com- 2.5 m. In consideration of the column-beam configura - parison, tried choice of material and size of structural tion and truss-step grid, the framework was adapted to components and envelope system. As a design research, befit. Laid out rather evenly, the vertical components it rehearsed the internal envelope before implementation were sectioned by 90 × 90 mm, while the 90 × 30 mm in Cihu Academy. horizontal ones chosen as double beams, fixed with bolts that clamped the column within. Along the depth, grade beams (90 × 90 mm) were overlaid, 4.2. Practice of “internal envelope” strategy in then keels (40 × 40 mm) spaced by 510 mm and finally Cihu Academy composite bamboo flooring (Figure 5). 4.2.1. Founding background and exemplary The two lecturer’s lounges on the upper floor significance of Cihu Academy adopted a similar framework with a reasonable adapta- As a complete and comprehensive implementation of tion to the existing floor slabs of modest load-bearing; internal envelope the concept, Cihu Academy is then, each reinforced with an entire box structure that endowed with explorative and exemplary significance. also formed the programmed tatami. In the meantime, Putian Wu, Cihu Academy. (Open Times. 2015)(1). Academy called Shuyuan in Chinese, literally book-courtyard, flourished since the second millennium of imperial China, was actually a succession of the Buddhist monasteries in both classical studies and elite education, only replaced into Confucianism and more active to participative in local administration and charity. Qinghua Guo, “‘Lifting beams’, column-and-beam frame: A type of building structure characterised by the placement of beams on columns repeatedly till a ridge is formed. Its basic structural unit is a bay which is made of four columns and beams. When a large space is required, it can be achieved by manipulating the dimensions of the skeleton or expansion by adding structural elements either at the front, the back or both” (Guo 2002, 76–77). 8 L. GUO AND C. ZHAO Figure 3. Outside view of Cihu Academy (photograph by the authors’ atelier, March 2015). Figure 4. Section of seminar rooms and lounges (drawn by the authors’ atelier, August 2013). Figure 5. Interior view of seminar rooms (photograph by the authors’ atelier, March 2015). JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING 9 Figure 6. Interior view of lounges (photograph by the authors, March 2015). the upward structure was also lessened in weight by the envelope under the pitched roof, laterally ventilat- narrowing the sections, namely the vertical to ing by the height difference. 90 × 60 mm, the box structure panel to 18 × 290 mm, the latter right overlaid the existing floor slab (Figure 6). 4.2.4. Performance of the project Completed in 2014 and put into service in autumn in the same year, Cihu Academy has been since then the 4.2.3. Envelope and other construction measures venue for many an advanced conference and lectures, In the vertical direction, furniture was incorporated bringing remarkable vitality to the district and even into the internal envelope, where it was a seminar, it invigorating the peripheral courtyards with newly became an open bookshelf taken the coupling posts introduced contents from Airbnb styled hotel, work- offsetting the existing middle columns as its skeleton, shop, restaurant and cafe. and where it was a lounge, it is turned into a wardrobe Cold and wet as it is, a typical southern winter there likewise. As for materials, the branded oriented strand proved to be the high time to examine the thermal board and polycarbonate hollow sheet were chosen. performance of the internal envelope. In unheated All windows and doors were opened in the sliding way, days, the internal-enveloped seminar and lounge were and the window casements and door leafs were, chosen in comparison to bare rrooms for temperature. respectively, polycarbonate hollow sheet high in And the data collected in a passive way on 8 and 9 light-transmittance and oriented strand board. February 2015 for 24 h showed an obvious advantage Before the project, the ground floor was solid wood of the former group over the compared ones. In parti- over keels that harboured dampness causing many a cular, at 7:00 on 9 February 2015, when the outdoor damage, to which anti-moisture procedures were con- temperature was −1.5°C, the seminar room had its ducted with waterproof roll and cement pressure indoor temperature as 7.8°C in contrast to that of the board that meanwhile reinforced the load-bearing bare middle hall, 5.1°C; on the average, in the seminar strength. As for the flooring, it was keels and compo- and lounge, it was warmer by about 2–3 degrees than site bamboo upon the internal envelope’s grade the non-internal-enveloped interiors (Figure 7). For tem- beams on the ground, and box structures as tatami perature differences, at the veranda, it was 9.1 degrees, covered with pallets upstairs. To enhance the sound in contrast to the seminar where it was 1.3 degrees; the insulation usually low of wood floor slab, a 10-mm- considerably less temperature difference testified the thick damping cushion was added between the upper heat preservation effect of internal envelope, which flooring and the main structure. Atop the envelope means the necessary use of air-conditioner in high win- overhead the upper floor, the ceiling’s 10-mm-thick ter and summer will make more with less. polycarbonate hollow sheet that incorporated the strip lighting and electric pipeline. For air-conditioning, it is downsized into two minor VRV sets that facilitated 5. Conclusion the outdoor units to be hidden from view in the court- From the angle of architecture as design researches to yard. Usually sectioned by 70 × 50 mm, the square creatively solve spatial problems, the traditional build- refrigerant piping was lead inside beneath the eaves- ing is centered on contemporary interior space rafters, while the blower fixed on the stepwise top of 10 L. GUO AND C. ZHAO Figure 7. Temperature comparison graph (drawn by the authors, March 2015). regeneration, so as to respond to the dilemma in his- envelope is expected of further practice, promotion, torical towns/districts revival as successful reuse. To deepening and refinement. It promises substantial provide the optimal interior comfort up to date with- progress to make in analyzing and researching mate- out compromising the strictness in preserving and rial selection for applicability and behavior scale, displaying the traditional building in its full view and along with digging in detailed design, manufactur- forms intact, the concept of “internal envelope” came ing and construction. And once so universally right into being. Yet an assumption remains an accepted as to be methodologically interiorized in assumption unless it is implemented for real values. the restoration phase of traditional buildings for Therefore, despite a long lay-aside after first proposed reuse content and programme, it will make greatly in 2007 with related basic studies, it is fortunately for the construction phase in saving input. As its plunged into practice in 2013–2014 as a solution to values and potential promises, “internal envelope” Cihu Academy the project. Not only the conception will be continuously explored. and methods of the design were thoroughly effected but also the implementation strategy continuously Disclosure statement fed-back from the real conditions. The final outcome passed basic data examination in interior comfort and No potential conflict of interest was reported by the authors. received acclaim in public event accommodation. Thus, profound potential is to be anticipated in histor- References ical towns/districts revival with the help of internal envelope, now that well proved. Different from most China Architecture Design & Research Group, Architecture restoration researches concerning formal imagery and History Graduate School. 2007. Zhe Jiang Vernacular tectonic techniques as they are, the internal envelope Architecture. Beijing: China Architecture & Building Press. takes the new contents and activities in real context as Frampton, K. 1996. 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Journal of Asian Architecture and Building Engineering
– Taylor & Francis
Published: Jan 2, 2021
Keywords: “Internal envelope”; traditional buildings; adaptive reuse; interior comfort; regenerate