Prefabrication experiments - 434 - XL(slabs) - Umbrellahaus TM

Modular volumetric construction is characterized by three-dimensional, factory produced boxes. This approach sometimes associated with slab buildings, is generally based on repetitive structural grids conducive to typical floor plates; flats with similar dimensions and attributes are simply stacked and coupled. The slab typology doesn’t expressly direct to volumetric as the sole solution for putting these buildings together, however, coordinated, transportable boxes can certainly streamline certain parts of a construction timeline. Further, modularity can be leveraged toward scaling container-like flat types among many housing projects using the same basic structural elements and systemic components - a strategy now identified as a platform approach to building. 

 

Designed and trademarked by Chapman Taylor www.chapmantaylor.com   Umbrellahaus deploys the current interest in offsite along with modular volumetric reasoning in the UK to demonstrate a building «platform» to tackle current housing shortages. Suites are outlined by industrial parameters, notably, manufacturability, transport maximum dimensions, assembly and setting details. All apartment unit sizes follow the London Plan space standards.  These design and production considerations are matched up with a variety of lifestyle compositions to propose an array of dwelling configurations from studios to family apartments within the overall framework of a slab building.

 

The concept encompasses more than just modular volumetric construction as it proposes to connect new buildings to their contexts proposing a multifunctional urban infrastructure to avoid the segregation and difficult living conditions connoted by mono-use post-war prefab block neighborhoods. Once the units are stacked in place, several cladding or material solutions can be applied to suit site conditions, architectural tastes and building arrangements. Standardizing design criteria along with a streamlined regulatory approval and a liability framework, the Umbrellahaus platform covers every aspect of the project procurement process.

 

The proposal also addresses long-term adaptability; inhabitants could change from one unit size to another as their circumstances change, without leaving the building. While this certainly can help overlay the units’ design options in tune with lifestyle evolutions - it remains unclear how this theory would be put in place in a densely populated building.

Modular volumetric Umbrellahaus

 

Prefabrication experiments - 433 - XL(slabs) - Streets in the Sky

 

Known for their important contribution to Team 10, an architectural collective formed from the Congrès Intérnationaux de l'architecture moderne's (CIAM) dissolution, Alison and Peter Smithson’s theories and projects were a fundamental part of nascent postwar brutalist visions and pedagogy in the UK and abroad. Mat-building previously discussed in blog article 282 envisioned urban form that rejected buildings as singular objects, exploring instead a symbiotic spatial relationship between urban geometry and building topologies. 

 

The couple married in 1949 and founded their own firm in 1950.  Their radical visions for integrating public spaces in collective housing led to imagining access walkways as «streets in the sky» redefining the slab type. The iconic Robin Hood Gardens, a social housing complex in East London, demonstrated the use of exterior access corridors at different levels large enough to support both personal and social spaces. Their design deconstructed the classic slab by placing these common voids within the structure's volume. A proposal, Terrace Housing City, took this one step further by arranging an oblique slab cross-section as a series of vertical volumetric setbacks from floor to floor flooding each floor plate's exterior skywalks with sunlight. The Streets in the sky imagery influenced many social housing proposals aiming to attribute streetscapes' spatial richness refuting the boring interior corridors synonymous with the slab. 

 

The construction of floating social spaces including roof terraces had already been proposed by modern architects, proficiently by Le Corbusier. Aerial passageways leading to flats became a symbolic component of these modernist visions and were applied most notably at Habitat 67 designed by Moshe Safdie.  Contemporary architects also reframed and refreshed the same objective of social interaction in a dense block: French architect, Jean Nouvel, designed a ship like cross-section at Nemausus in Nîmes, France, with large promenade decks. Multiple meters wide, the catwalks leading to access and exit stairwells were planned as a way of rationalizing costs by externalizing costly elements usually built within the slab. Their removal allowed for them to be built with lighter construction systems and materials redirecting these potential economies to offer larger housing units.

Sections though aerial walkways

Prefabrication experiments - 432 - XL(slabs) - ZUP at Bayonne

 

Interwar years in France intensified dwelling as well as urban hygiene crises. An estimated 5 million units lacked running water and basic services. The devastating damage to hundreds of thousands of buildings during the second world war exacerbated this need for quality housing. In response, centralized policy sanctioned new dense developments all over the country under the label, ZUP - Zones à urbaniser à prioriser (liberally translated to Priority Zones to Urbanize). Projects and their promoters which provided a minimum of 500 units in tightly packed edifices required affordable and efficient construction methods to be deployed at scale. 

 

The slab block was adopted by an industry increasingly articulated to reinforced concrete; a material the country's inventors (Hennebique, Monier, Lambot and many others) had been central in cultivating. Beyond the material's advantages in terms of fireproofing and strength, it also lent itself to all types of prefabrication strategies. Marcel Breuers' flagship ZUP design for 1100 units at Sainte-Croix/Saint-Esprit, in the small community of Bayonnne explored precast concrete construction to propose a formidable building system. Designed and built from 1963 -1967, the master plan included dwellings and several services including a school and shopping center.  

 

Using a factory cast wall panel system inspired by the Camus System (also invented in France), Bayonne buildings were arranged as a cellular hive of flats and simply covered in a precast thick panel. The basic structural strategy of walls and slabs at Bayonne was cast on site using a tunnel form system:  a moveable prismatic formwork that defines a cell with a horizontal plane supported by two vertical planes. The tunnel forms are usually made of steel. Once the concrete is cast, the steel framed-moulds slide out and are reused on subsequent floor plates. 

 

The heavy wall panels’ architectural treatment at Bayonne showcase Breurer's talent and understanding of prefabrication's potential to create dynamic façades using mass manufactured components. The panels were cast as a thick solar shading device with built-in furniture and window openings. A mirrored pattern was repeated every two stories creating a textile like façade; the project's simple renderings illustrate how architectural regularity defined a coherent material field. 

Rendering of the Bayonne master plan

Prefabrication experiments - 431 - XL(slabs) - A failed prototype ?

 

Generated from industrialization and its new construction materials, specifically, reinforced concrete, the slab building was forged by assembly line production and its accompanying design theories. Thin, linear, rigorous grid organizations simplified structural design and service distribution, making these replicable arrangements ideal candidates for scaled serial production. The linear apartment blocks repeat floor plans and extrude sweeping vertical sections that sometimes seem to go on infinitely. This regularity is what made the slab a formidable affordable housing strategy but what also ultimately embodied the downfall of this expressly modern type.

 

Inaugurated in 1954 in St. Louis, Missouri, Pruitt-Igoe's 33 high density buildings underwritten by federal policy heralded the post war enthusiasm and urban planning doctrines associated with the slab block. The experiment like so many other modernist developments was rife with economic and social challenges.  Its symbolic demolition only years after its construction refuted modernist ideologies of mass housing.

 

Still, the slab endures as an iconic composition of flats designed to optimize collective and social cohesiveness. These buildings offer a rational way of using the same principles that gave us terraced housing but scaling them to taller structures. Recent proposals deploy the same underlying ideas to produce buildings from a generic aggregation of flats contextualized in mixed-use settings to counterbalance flawed modernist functional segregation. 

 

A contemporary example of a contextualized slab designed by Arrhov Frick Arkitektkontor in Sweden, is composed of a dual-oriented adaptable loft inspired units.  The typical floor plate of the Hmmarby Gård project is a multiplied sequence of two flats articulated to a shared vertical circulation core and arranged around a service hub surrounded by flexible living spaces.  13,6 meters wide, flats include large balconies on their north eastern façade and operable curtain wall façades on the opposite connecting the see through building to its surroundings. The repetitive plan makes a case for modern industrialized principles, repetition, modularity, standardization. This reproducible sameness that was decried more than half a century ago is valued as fashionable and mass customizable, elevating the slab from a once promising but failed prototype into a dynamic way of breathing new life into a city.  

Hmmarby Gård typical floor plan