gilles retsin completes lego-like wooden pavilion for the tallinn architecture biennale

the tallinn architecture biennale 2017 has organized an international open two-stage competition, challenging participants to develop creative designs for a temporary outdoor installation in estonia, making innovative use of the fabrication capacities of the local wooden house manufacturers. the call raised wide international interest, 200 portfolios were submitted for the first round from all over the world and 16 works were selected for the second round by the jury. gilles retsin architecture was selected as winner, with a proposal that jury member martin tamke describes as ‘characterized by outstanding aesthetic and intellectually challenging, as it questions current beliefs and trends in architecture’.

the installation is set opposite to the estonian architecture museum and aligns with the neighboring buildings
image by studio naaro

the traditional construction industry makes on average use of more than 7000 different parts. this results in a complicated production chain, making building slow, expensive and inaccessible for many. what if we could radically reduce that number? london based architect gilles retsin‘s pavilion for the TAB 2017 is based on just a few lego-like pieces that can act as column, beam and cladding at the same time. the past decade has seen an explosion of parametric pavilion structures, built by architecture schools, research institutes and enthusiasts. these so-called ‘parametric pavilions’ are remarkably similar — they are almost always based on a surface or shell, that is then split into thousands of different pieces and then painstakingly re-assembled into the desire form.

gilles retsin’s pavilion is offset from the ground, standing on a series of steel profiles
image by studio naaro

this proposal is critical of this approach, and instead proposes to create a series of discrete building blocks, that similar to lego, can be assembled into a variety of structures. these building blocks are based on cheap, off-standard sheets of 18 mm exterior plywood which were locally available. each sheet is cut by a CNC-machine, and can then be assembled into a stiff building block capable of bearing structural loads. the blocks exist as a family of straight, 45 degrees, 90 degrees and 135 degrees elements.

this image shows a more informal organization of elements with a less defined outline

these building blocks are designed to perform ‘just good enough’ in any structural condition: under compression, tension, as a cantilever or as a column. the blocks are protected from the exterior climate with black bitumen tar or varnish. over 380 m2 of plywood has been cut and assembled into 80 building blocks. the entire structure was fabricated locally in tallinn, in collaboration with local manufacturers.

gilles retsin’s pavilion appears different from every side
image by studio naaro

similar to a brick-bond, these discrete building blocks can be combined together into a staggered pattern, able to produce large beams and spans. the connection is based on off-the-shelf threaded rods, used in suspended ceilings or to hang cable gutters. these rods connect through several pieces, forming a stiff structure under tension. the blocks can be quickly assembled on site, using only a set of ratchet-spanners and bolts. the assembly remains reversible, it can be modified or taken apart afterwards.

the edges of the pavilion show the complex qualities of the discrete assembly
image by studio naaro

the whole pavilion, covering an area of 75 m2 was assembled in just 4 days by a crew of 4 people, without any mechanical tools such as a crane or lift. the pavilion is materially and structurally efficient: the overall weight of the pavilion is only 2 tons, while it can support local loads of four people and can be extended with a roof. using only 18 mm thin plywood, cantilevers of up to 4 m are achieved.

the blocks are protected from the exterior climate with black bitumen tar or varnish

the pavilion is more of a case-study or prototype of a construction system rather than a finished form. in that sense it’s similar to le corbusier’s ‘maison domino’ — an abstract model of a larger and repeatable construction system. in contrast to the typical shell or surface-like parametric pavilions, this pavilion wants to be understood as a part of a larger whole, a unit in a mass-housing system. the horizontal organization hints at the fact that it could be stacked and repeated in multiple directions.

the building blocks are designed to perform good enough in any structural condition

gilles retsin’s pavilion is never finished — it remains an open and adaptable whole. the structure could be finished with a roof or façade, and continue its life afterwards as a cabin, pedestrian bridge or house on another location. the digital workflow behind the pavilion enables a low-cost, fast and open production-chain. with the help of digital fabrication tools, an initially weak material is turned into a versatile and structural building block that can be assembled by anyone, with almost no tools. this construction method is scalable and could be applied for housing solutions on a larger scale using stronger materials such as CLT — cross laminated timber — or LVL — laminated veneer lumber.

building blocks are organised in a staggered pattern — a threaded rod combines two elements under tension

the pavilion can be continuously adapted or re-assembled into a variety of other structures

the building blocks are CNC-milled out of one sheet of plywood

the pavilion design deliberately doesn’t show any of the construction details, avoiding the ‘DIY-aesthetic’

the pavilion can be build using only one type of machine and a limited amount of tools

project credits:

designer: gilles retsin architecture 

design team: gilles retsin, ivo tedbury, oscar walheim

engineering: manja van de worp, nous engineering, yip structural engineering london

construction team: isaie bloch, ward delbeke, gilles retsin, kevin saey, ivo tedbury, oscar walheim

client: tallinn architecture biennale 2017 

TAB volunteers: mari poom, ra puhkan, mia peil, elsbeth aarsalu, katariina mustasaar, henri ingelman

TAB installation curators: sille pihlak, siim tuksam

with support of the british council

academic partner: the bartlett school of architecture, UCL design computation lab and estonian academy of arts

images: studio naaro

drone footage: tonu tonnul, manuel jimenez garcia

designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: apostolos costarangos | designboom