The Tectonic Potential of Design for Deconstruction (DfD)

Søren Nielsen, Olga Popovic LarsenThe Royal Danish Academy of Fine Arts, Institute of Technology, Copenhagen Denmark

AbstractAlong with the implementation of high standards for energy saving in new buildings furtherresource conserving action must focus on strategies for prolonging the lifetime ofbuildings, their parts, components and materials. Spatial and technical strategies must bedeployed to increase buildings' capacity for transformation according to change. Design forDeconstruction (DfD) is a technical strategy enabling changes in building configurationwithout generating waste. DfD has primarily been described as a technical matter, e.g.reversible connections and layering. However, the architectural potential is considerable,and actualises the concept of 'tectonics'; architectural expression by means ofconstruction. By systematically investigating the relationship between technical guidelinesof DfD and tectonic articulation, resource conserving necessity may turn into an attractiveinspirational source for architects. Through a number of case studies, relations are mappedand tectonic potentials are registered. Hereby, the architectural potential can be detected,documented and categorised as tectonic motifs.

Keywords: Resource conservation, Design for Deconstruction (DfD), tectonics, assemblydiagram, motif

1.0 RESEARCH AIM AND CONTEXTOn the background of a future agenda ofconserving resources, architectural designpractice is facing a shift in its technicalparadigm: From designing for permanence todesigning for constructive reversibility.This change will stimulate the technicalcore competencies of the architecturalprofession, actualising the concept oftectonics; artistic expression by means ofconstruction.The study described in the followingattempts to point out ways to describe theconnection between Design forDeconstruction (DfD) and architecturaldesign strategies. The motif generatingpotential of DfD is demonstrated throughtechnical and tectonic analysis of caseexamples.

1.1 The resource agendaToday in most European countries, thelowest hanging fruits of energy saving have

been reaped by saving energy for buildingoperation. To reach further goals,lifetime processes and embodied energymust be addressed as a design parameter.Though 50% of demolishing waste isrecycled, little is prepared for reuse andlarge amounts of resources are lost.The reuse ratio could potentially beraised drastically and huge amounts ofresources could be saved if buildings andcomponents were designed fordeconstruction. Technical guidelines mustbe taken into operation by buildingdesigners but the potential is far fromonly technical as cultural value tobuildings might be added simultaneously. While resources can be assessed by life-cycle assessment (LCA), the culturalassets of building identity cannot becalculated quantitatively, and yetidentity has the capacity to become themost critical factor of longevity, as

buildings that lose their cultural statusare more likely to be demolished.

1.2 Solution strategiesDfD, as technical solution and asarchitectural strategy, must be seen inrelation to the three main strategies forresource preserving: Longevity of buildings: Minimizing resourceconsumption for building interventions e.g.replacements, conversions, additions andmaintenance. This can be obtained byadaptability, e.g. versatility,convertibility and scalability 1, by meansof robust spatial composition: large freespans, generous ceiling height and surplusstructural capacity. Longevity of components: Avoiding wastegenerating and downcycling by technicalstrategies, e.g. refitability, movabilityand adjustability by designing fordeconstruction (DfD). DfD covers a widerange of guidelines and recommendations.Based on previous research 2 a short setof technical design rules of particularrelevance to architectural design,comprises:1. Reversible fixations, enabling

deconstruction without damage ofmaterials. This implies in generalmechanical assembly rather than chemical(cast, glued).

2. Hierarchical assembly according tocomponent lifetime, enablinginterventions with a minimum ofinterference in components with longerlifetime.

3. Accessibility of fixations, enablingdeconstruction without damagingcomponents.

4. Parallel assembly, enabling localexchange of single components.

5. Handleable size and weight ofcomponents, enabling changes anddeconstruction without crane-lifts.

6. High generality (modularity,homogeneousness and uniformity)increases the reusability of components.

7. Minimum of mechanical degradation, e.g.cutting, carving and penetration,minimises waste and increases thereusability of components.

8. Orthogonal geometries (rather thanskewed or curved) minimises waste andincreases the reusability of components.

9. Minimal number of component types easesas well the deconstruction as thesalvaging process.

Cultural value: longevity can be pursuedthrough cultural value by achievement of aprotecting 'lovability' 3. As only aminority of buildings will achieveprotection or even conservation, DfDconstitutes a 'safety net strategy' byensuring the possible salvaging ofbuilding materials for reuse at end oflife. By cultivating DfD to increasecultural value, e.g. by exquisitedetailing, a double, strategic 'safetynet' can be held under the buildingresources. 2.0 TECTONICSHow can DfD be deployed in order toincrease buildings' cultural value?Constructive reversibility, as the primarycommand of DfD, highlights thesignificance of bringing constructiontechnology into the very centre ofarchitectural design. In this respect, thenotion of tectonics might be a key toevoke a new resource saving buildingculture.Tectonics can be defined as 'a certainexpressivity arising from the statical resistance ofconstructional form' 4 and correspondingly: 'theatectonic: visually neglecting or obscuring the expressiveinteraction of load and support'. The followingcases represents an approach to linktectonics with DfD in a systematic way bydemonstrating how DfD is simultaneously anengineering discipline and anarchitectural strategy: Architecturalmotifs are generated from hierarchicalassembly according to lifetime layers andfrom features of mechanical assemblyenabling such as bolts, brackets, screwsor springs.

3.0 METHODOLOGYThis study is based on investigation andanalysis of four case studies chosen amonghousing schemes, the functional categoryconstituting 75% of the total built area:Two high-profiled demonstration projects,

and two ordinary low-cost residencesdisplaying deconstruction as an inherentpart of industrialised constructionsystems. The cases below are all designedto meet contemporary regulatory standardsfor building insulation.

3.1 Analytic toolsCases are analysed in parallel:Technically, by assembly diagrams, andnarratively, by denotation of the tectonicprinciples behind the architectural motifs.Assembly diagrams

The assembly-diagram translates actualtechnical solutions into visualisations ofcomponent placement in a layered structure.By analysing the assembly structure, theactual capacity for deconstruction isdocumented by ensuring that disassembly cantake place without interference in morepermanent neighbouring layers. From theassembly diagram it is possible to map thelogistic and technical functionalities thatconditions the tectonic motifs.Detail drawings

Narratives attached to the technicalsolution unfold in the scale of the detail5, making the 1:5 drawing the primarystudy object, fig. 1. On the technicallevel, constructions are describedaccording to the functionality of thecomponent, and the delineation between DfDand non-DfD parts are marked and similarlyare marked a boundary between off-site andon-site construction.

Figure 1: Principle diagram; parallel studyof technical principles and tectonicmotifs.On the tectonic level, constructions aredescribed as actions of designing, such as'hanging', 'clamping', 'penetrating', etc.,and denoted by pictograms. These actionsrepresent architectural motifs attached tothe assembly technique. By identifyingbasic form principles from actual designs,an 'alphabet' of tectonic categories can bedeveloped.

3.2 Case presentation

Case 1: Bolig+ by Vandkunsten 2009 is ascheme for an open building system withenergy consumption below zero obtained bymeans of passivehaus technology andintegrated renewable energy sources.Spatial versatility and reversibleassembly technique are employed as long-term resource-saving strategy.In order to separate the more volatileskin layer from the permanent structurallayer (prefab concrete elements), nonthermal-conducting intermediary consolesof fibreglass are attached to the slabedges, resulting in a gargoyle-like motif,fig. 2, onto which additional applicationscan be mounted such as balcony element,sunscreens or windshields.

Figure 2: Vandkunsten Bolig+: consoles forconnecting climate shield and applicationsto structural layer.

The separate structure and skin layers arevisibly displayed in the interior, fig. 4,as a double framing motif enforced bydifferent materials: concrete and wood. Inthis, the motif appears as a combinationof two layers. The console elementexemplifies how mechanical connections canbe designed as autonomous componentsrendering an architectural motif, figs. 2-6.

Figure: 3: Vandkunsten Bolig+, assemblydiagram.

Figure 4: Vandkunsten Bolig+, proposal forzero-energy residences 2009, interior withexposed layering of facade elements.

Figure 5: Vandkunsten Bolig+, proposal forzero-energy residences 2009, section offaçade.

Case 2: Kvistgård by Vandkunsten is a scheme forlow-dense, low-cost residences built withprefabricated panel-elements. The buildingsare assembled in a way that enablesreversible action. By turning the cladding

board from vertical (pre-mounted) tohorizontal (mounted onsite) the assemblyconnections between panels are manipulatedinto a characteristic motif of two layersof boxes sliding on top of each other,figs. 7-8. As the stud-frame structure isatectonically hidden by cladding on bothsides, all visible motifs appear in theskin layer, fig 9.

Figure 6: Vandkunsten Bolig+, façadedetail.

Figure 7: Vandkunsten 2007 Kvistgård.Photo by Adam Mørk.

Figure 8: Vandkunsten Kvistgård, low-denseterraced housing 2007.

Figure 9: Vandkunsten 2007 Kvistgård,façade detail.

Figure 10: Vandkunsten 2007, Kvistgård,assembly diagram. Structural members andthe complete skin layer are integrated inprefab panel elements except for the on-site façade cladding covering theconnections. Case 3: Almen+ by Vandkunsten is a scheme for low-cost terraced housing based on prefabvolumetric elements with stud-framestructure and cladding of hard, fibre-reinforced gypsum. While connections between volumes arehidden, the secondary construction for thefaçade cladding comes to define thedominant exterior motif, figs. 11-14:Pitched boards, reflecting the on-sitemounting process where boards are placed inposition from a lift. By using stock-

measured board modules and frictionalfixation screws, instead of drilledpenetrations the cladding construction isdesigned for disassembly. Rhythmicallyplaced steel hooks generate acharacteristic motif.

Figure 11: Vandkunsten, Almen+, section offaçade module.

Figure 12: Vandkunsten 2009, Almen+, blocktypology.

Figure 13: Vandkunsten 2009, Almen+,assembly diagram.

Figure 14: Vandkunsten 2009, Almen+, façadedetail.

Case 4: The Loblolly house is a single-familyholiday residence designed for a maximumdegree of prefabrication. The structure isa patented scaffolding system of extrudedaluminium profiles assembled with steelconnections forming a 3D framework in whichwooden stud-frame volumes are inserted.In Loblolly House a series of motives aredisplayed in parallel, each one of themconnected with the respective constructivelayer: The structure designed by the

Figure 15: KieranTimberlake, LoblollyHouse, assembly diagram. The constructionperforms a full DfD-design as even thefoundation can be dismantled.

Figure 16: KieranTimberlake, LoblollyHouse 2008, exterior. Photo by UlrikStylsvig.

manufacturer (Bosch) becomes an adoptedmotif, whereas the fragmented sections ofpre-fabricated wooden façade claddingstand out as an original, individuallydesigned motif. In terms of layering, thewooden boards constitute a mere surfacefunction of the skin layer, locating thebuildings' exterior identity in the mostvolatile part of the assembly hierarchy.

4.0 INTERPRETING DFD-RELATED MOTIFSFrom the cases analysed above, thatexemplifies how reversible assembly and

tectonic motifs correlate, a number ofphenomena can be found.In all cases it is the structure and skinlayers that are subject to articulationefforts, whereas service, space plan layersappear atectonic due to hidden connections.In other buildings motifs might be foundemerged from those layers.

Figure 17: KieranTimberlake, LoblollyHouse, facade detail.The motifs found in the four cases arerelated to the DfD-principles as displayedin the matrix below, fig. 18. From thematrix a number of characteristic featurescan be found:1. Unexploited potential: The matrix makes itvisible to what degree the DfD guidelineshas not been a vehicle for architecturalexpression.2. All DfD guidelines are potentially motif-generating:Motifs are found with all categories ofguidelines.

3. Mechanical, connections are most rich in motifs:Mechanical, accessible connections,typically found with steel and aluminiumjoints, produce significant motifs oftenwith ornamental and decorative qualities. 4. Super-motifs: Some motifs are found torelate simultaneously to a multiplicity ofguidelines, e.g. the sliding motif inKvistgård and the frame-structure ofLoblolly. 5. DfD-related motifs are found along with non-DfD-related motifs: Even when DfD principles arefollowed consequently motifs emerge withno reference to DfD. At the level ofvolumetric composition motifs are foundwhich are not specific to DfD thoughproduced by DfD assembly methods.6. Scale: Tectonic articulation, by means ofreversible assembly details, materialisesat different levels of scale. Assemblydetails can generate motifs in macro-scale. In the Kvistgård case thedisplacement of volumes is narrated as anevent of sliding on the ‘rail’ of thehorizontal cladding. Loblolly’sscaffolding grid attains a three dimensionplug-in motif at the volumetric scale.Motifs such as stacking, sliding,segmenting or cantilevering are found tobe scale independent.

7. Lifetime layers Constructive layering initself can produce significant motifs atmultiple scale levels as found in theframe-and-filling motif of Loblolly andthe double frame motif of Bolig+.

Figure 18: Matrix showing tectonic motifs'relation to DfD guidelines.

In insulated constructions the mostidentity constituting elements can be foundas highly peripheral parts of thestructural hierarchy, which confirms thatthe narratives of modern architectureunfold at the surface level as aconsequence of technical independencybetween façade and structure 6. Within aDfD regiment buildings become 'paper-dolls'allowing the exterior identity to be easilychanged by tacking façade element tointermediate structures. This strengthensthe buildings' robustness but challengesauthorship by assigning influence to usersand second-generation designers. 5.0 CONCLUSIONThe DfD building technique is capable ofbeing integrated in architectural design asa resource of motifs that can be used foradding individual identity to buildings.The relationship between technicalguidelines and motifs can be decoded asattempted above and a multiplicity ofarchitectural expressions is revealed.

5.1 Architectural potential

Architects may on the one hand dismisstectonic opportunities in DfD in thestructural layer when members are

integrated due to insulation thickness,but numerous motifs can be created withinand between the more volatile layers. Thisimplies an increased focus on buildings'details, including assembly logistics thatare, however, somehow peripheraldisciplines in much architectural designpractice. Bringing the methods of DfD intothe core repertoire of design practicemight change this picture and result inlong-term resource savings. Though thecommitment to technical reversibilityimposes some new restrictive conditions tothe design framework, new means forexpression occur from finding constructivesolutions to the challenge.

5.2 PerspectivesBy incorporating DfD in the repertoire ofarchitectural profession as a means ofexpression, the development towards aresource-gentle building practice can bepushed forward. While there is a developedbody of knowledge on the technical aspectsof DfD, the architectural potentials ofDfD are still relatively unexplored,partly due to the lack of empiricism.Further research in e.g. the potential ofspecific materials, technicalfunctionality or architectural themes canexpand the field.

The architecture of DfD might eventuallyhave a cultural perspective: DfD may changethe ways buildings are conceived into a

more dynamic direction, since DfDtechnically allows an increased influencefrom users and other_stakeholders.

1 Schneider, T. and Till, J. 2007: Flexible Housing, Elsevier Oxford2 Addis, W. & Schouten, J. 2004. Design for deconstruction. Principles of design to facilitate reuse and recycling. London: CIRIA, Durmisevic, E.2006: Transformable Building Structures, Doctoral thesis, Technical University Delft, Sassi, P. 2008: Closed Loop Material Cycle, Doctoral thesis, Cardiff University, Nordby, A.S. 2009. Salvageability of building materials. Doctoral thesis NTNU3 Eberle, J. in: Nerdinger, W. (ed) 2007: Baumschlager+Eberle, Recent Projects 2002-2007 Architecture, People and Resources, Wien, Springer4 Eduard Sekler, "Structure, Construction & Tectonics" in Structure in Art and in Science,New York, 1965, pp. 89-95.5 Frascari, M. 1984: The tell the tale detail – in Via7, University of Pensylvannia p. 23-376 Leatherbarrow, D. and Mostafavi, M. 2002: Surface Architecture, The MIT Press, CambridgeMassachusetts