Mario Carpo

Publication History:

“Point Blank.” Essay and book review of Jennifer Bonner and Hanif Kara, Blank. Speculations on CLT.  New York Review of Architecture, 29-30 (summer 2023), 34-35.

The text posted here is an earlier draft and it is different from the published version. Please only cite from copy in print.

Timber is popular these days—hailed by some as “the new concrete” and the future of construction. This is mainly due to the environmental qualities, and carbon benefits, of natural wood: trees absorb carbon dioxide from the atmosphere and convert it into various organic materials, including wood, where CO2 remains sequestered so long as the wood in question doesn’t rot or burn. Additionally, if a tree is felled, and its wood is used to build a house on the same spot, the embodied carbon of that wood, when turned into a building material, is close to zero.

The problem with wood is that, as often happens in nature, trees tend to all be different from one another, so when we chop one down we cannot tell in advance what kind of timber we will get out of it. Artisan builders of old knew how to deal with the random variability of natural materials; they also knew how to adapt construction to the materials they would come by. Modern engineers on the contrary, working as they do by remote control—by design and notation—need all building materials to be calculable and predictable. So they have invented over time a range of “engineered” timbers, obtained from wood that is carried from a forest to a factory, dismembered and reduced to layers, particles, or pulp, then glued and pressed and served to builders as an industrial material, in standard, performance-tested formats.  

Plywood was the first and most successful engineered timber; apparently an Austrian invention and in use as of the early 1990s, cross-laminated timber, or CLT, is a more recent development of the same principle. Think of it as sturdy structural plywood with thick layers glued together in alternating directions, to obtain an almost isotropic (if not really elastic) panel with equal structural performance on the x and y axes, so the same panel can be used for axial and bending loads alike—quite unlike plywood, which has no structural resistance of its own. CLT panels are large (around nine by fifty feet, though smaller panels can be recut on demand inside this frame) and entirely prefabricated: digitally milled to specs, with all openings (doors, windows, rabbet edges, and perforations for panel-to-panel connections) cut into the body of the panel, they are delivered flat-packed and numbered for assembly: Jennifer Bonner’s Haus Gables in Atlanta (2018), a single-family house, and a seminal and striking demonstration of method, was made in full out of eighty-seven such panels. 

CLT panels used to be called, in the technical lingo, “blanks,” but—and this is the gist of this book—their blankness becomes here, metaphorically, an aesthetic value, part of a core architectural agenda. That is not to say a new architectural agenda: the book—edited by Bonner, a designer, and engineer Hanif Kara, and comprising essays, design projects, art installations, and student work—is the latest emanation of an architectural trend that has been around for some time now, which happens to have found in CLT the perfect building material to match its aesthetic ambitions, thus offering a conduit to advance and promote a certain architectural style.

Nobody knows for certain why many young designers in the last fifteen or twenty years started cherishing collage-looking but digitally made compositions, particularly of a rough, disjointed, angular, and conspicuously fragmentary kind. Originally, a commonsense motivation could have been the rejection of the smooth and fluid style of digital streamlining and hyperrealistic computer graphics, often seen as a sign of the digital turn in architecture.  But collages in art have a confusing, multifarious lineage: a modernist invention, they were originally devised as a commentary on and a critique of the machine-made environment; Braque’s, Picasso’s, and Gris’s collages were assemblages of printed or stenciled typographical characters, of mechanically printed wallpaper, or of actual newspaper pages. In 1959 Clement Greenberg, the pontiff of high modernism, wrote a famous essay, still required reading in departments of art history around the world, extolling collage as the core theoretical trope of modernist art. 

Yet, inexplicably, as of the late 1970s and early 1980 collages became a post-modernist battle cry and almost a PoMo obsession, loaded with ideological, sometimes reactionary political connotations (particularly in the historicist version advocated by Colin Rowe), and occasionally inspired by post-structuralist linguistics (see Julia Kristeva’s and Roland Barthes’s coeval invention of intertextuality—a theory whereby all texts are seen as the reassembly of preexisting fragments, or citations). So from today’s post-digital perspective, the revival of the cut-and-pasted, cut-out compositional style may betoken, alongside a visceral aversion to today’s technology, a nostalgia for either high or late modernist machinism, or for historical, neo-Luddite postmodernism—or, oddly, all of the above.

Be that as it may, it stands to reason that designers who have long been aiming at drawings and buildings that appear to have been cut and pasted (regardless of how they are made and what they are made of) should now be fascinated by a building technology that promises to deliver cut-and-pasted buildings—in this instance, literally: as the CLT blanks are digitally cut in a factory then mechanically pasted on site (even if nuts and bolts are more frequently used for assembly, hence Nelson Byun’s essay on Matisse’s pinned-up decoupages). CLT blanks can be used to build actual buildings that look like blown-up balsa-wood scale models, where all the usual structural components—walls, columns, and beams alike—are replaced by flat, flimsy planes, crisply milled and intersecting at sharp angles; and as CLT blanks, being planar surfaces, are ready for use as load-bearing walls, floors, and ceilings—but cannot be easily turned into columns, pillars, and beams—the tectonic logic of the ideal CLT building favors a cellular structure of stacked, shoebox-like, seamless enclosures. 

This is exactly what modernism, thanks to steel and reinforced concrete, was supposed to do away with and deliver us from—hence the neoplastic and cubist break-up of load-bearing perimeter walls and angles, and the invention of free plans, curtain walls, and other staples of twentieth-century architecture. All this is now put into reverse motion by this stylistically driven adoption of CLT technology—in this respect the expression of a clear antimodern stance, as Kara himself does not fail to notice. But anti-modernism was not invented yesterday, and Bonner is right to point out, very perceptively, that Aldo Rossi would have loved CLT, had he lived to see it; and Sean Canty’s edge-cutting geometries (which, by the way, for the most part cannot be built in CLT, due to their curviness) appear similar in spirit and form to some of Valerio Olgiati’s early work (except that Olgiati’s most memorable monoliths were built in single-cast concrete).

But this is only part of the story, because CLT is a very versatile technology. Transportation and assembly of CLT panels require sizable logistics and heavy cranes, but the assembly itself is a speedy and purely mechanical operation, ideally reducing the need for traditional on-site construction work, to this day carried out by quasi-artisanal, retardataire building trades (a point emphasized here by Nader Tehrani’s essay). Many mainstream builders have already largely adopted CLT technology without fanfare, due to its mere convenience and price; in the absence of specific aesthetic pursuits, CLT panels are often hidden behind traditional cladding and run-of-the-mill surface decoration.  

Indeed, Blank itself offers plenty of evidence of other, non- “post-digital” ways of building with CLT: for a striking case in point, see Yasmin Vobis’s and Ultramoderne’s CLT-roofed Chicago Horizon pavilion (2015), which deliberately referenced Mies’s Neue Nationalgalerie in Berlin. Likewise, projects from students in Bonner and Kara’s studio at the Harvard Graduate School of Design (who also contributed some remarkable short essays) look at times neo-deconstructivist, at times “particlized” in the manner of Kengo Kuma, at times similar to the “mereological” style of Daniel Köhler and other designers of the so-called second digital turn. 

Crucially, as Bonner emphasizes, CLT is bound to disrupt “a nostalgic view of materiality.” Regardless of some dissenting views of technology that occasionally transpire in the book, CLT is not for tech-bashers. Cross-laminated timber is, by its very nature, high-tech; it requires state of the art computational design and digitally mass-customized fabrication; it is primed for AI-powered, on-site robotic assembly; its mode of fabrication—currently still based on centralized manufacturing—could theoretically evolve toward distributed, sustainable, and localized micro-factory networks. Time will tell. But this may well turn out to be the long-awaited tipping point where post-digital fatigue gives way to a new digital design agenda—one attuned to a postindustrial, post-anthropocenic world.        

Jennifer Bonner and Hanif Kara, eds., Blank. Speculations on CLT. Novato, CA: Oro Editions, 2021. 240 pages, richly illustrated, $ 49.95 (cloth), ISBN 978-1-954081-02-4.