Prefabrication experiments - 423 - MLXL (row-houses) - Mat-building - Dense Pack Village

 

Organizational systems conceived for affordable housing are in a sense related to the same efficiencies required for profitable industrial production: Standardization, repetition, and scalability can all lead to both affordability and profitability. These same concepts are intrinsic to urbanized structure. Strict geometries, grids and modular massing are the building tools of urban planning. 

 

The townhouse, the row-house and terraced housing are great examples of affordable housing theories fused with widespread building culture deployed toward inhabited city blocks. Spaces can be further densely packed from linear geometries common to cities into an intricate geometric weaving of public and private areas massed in a thick field referred to as mat building.  In a compact interconnectedness dwellings or other functions are laid out within the quilt-like patchwork repeating the same composition clusters in a planar field one or two stories high. The term was first used by Alison Smithson in 1974. Architect and author, her article How to Recognise and Read Mat-Building described and analyzed the potential of this modern as well as vernacular architectural archetype. 

 

The mat is a horizontal matrix where grid informs both units and structure. Steven Holl's Dense Pack Village proposition for Haiti experimented with the idea of an inclined mat-building using inclination as a site anchoring device. Imbedded in the existing topography and envisioned as a terraced landscape where each unit would receive equivalent light and spatial qualities, the mat formula is a decidedly democratic urban form; virtues outlined for one basic kernel are multiplied in a highly rationalized manner.

 

Developed in the aftermath of the devastating 2010 earthquakes, the Dense Pack uses a diagonally divided square grid to fashion a mass / void relationship in its basic courtyard housing prototype. Each is then aligned, juxtaposed and multiplied to form an inclusive sheltering earthwork. The inclined plane is supported by a service space running parallel to each house. The square inhabitable earthwork optimizes solar shading, natural ventilation, thermal mass, and grey water recycling to reduce the building’s ecological footprint and to demonstrate a model of housing form harmonized with its sloping setting.

Mat-building Steven Holl's Dense Pack Village

Prefabrication experiments - 422 - ML(row-houses) - Modular infill dwellings

 

The townhouse is arguably the most appropriate housing type to adjust for prefabrication. Tracts are apportioned into aligned lots with similar dimensions and organizing principles. Based on repeating these patterns, coherent streets of townhouses iconically represent dense city dwelling without the sameness of housing blocks and bars connoted with 20^th century mass housing attitudes. Construction techniques are also shared among neighboring units, each portion, part of an open-air assembly line, using the same processes, materials and industrialized parts; The balloon and platform timber fames spanned from one party wall to another supported stacked stories, flats and made it possible to build a plethora of workforce housing blocks in evolving modern cities. 

 

Today many of these emblematic city blocks are still standing, restored and being updated with infill replacements. These infill dwellings are conducive to rationalizing construction as some elements can be repeated over multiple project settings: dimensions, heights, materials, organizations. Module, a creative modular housing company from Pittsburgh, Pennsylvania, USA has made this type of infill dwelling their sustaining business model. While typologically different from party wall developments, similar site parameters are scaled to deploy a modular volumetric platform for zero-energy ready townhouses. The factory produced boxes can be stacked two to three stories high. 

 

Like most modular companies attempting to showcase a successful industrial process for greater productivity and affordability, the company offers an all-in-one shop from design to fabrication to construction with some adaptable townhouse models even evolving from 2 to 3 floors over time, based on fundamental core-house principles. Catalogued on-line, engineered-to-order boxes are produced in the factory while foundations and services are completed on site. Boxes are then delivered and anchored to site foundations, reducing schedule length and maximizing offsite quality control. The infill patterns also simply the procurement process as multiple townhouses can be manufactured simultaneously with the same production parameters. Using contemporary 3d modelling, virtual design and construction, performance can also be monitored over time taking control of design, fabrication, delivery and operational aspects of the home to further optimize the houses’ lifecycle and durability. 

Module's Infill prototypes

Prefabrication experiments - 421 - ML(row houses) - The town house as an urban archetype

 

Urban dwellings feature the potential of densely packed zoning to increase affordability, livability, socialization, and infrastructure sharing, all pillars of sustainable cities. Their narrow frontage inscribed within a rhythmic alignment transforms the detached villa's enfilade of rooms and spaces into vertical organizations articulated to a staircase; different stairwell locations lead to various configurations. Treatises and pattern books have defined some fundamental principles: The American House Carpenter (R.G. Hatfield, 1852) illustrated construction systems and possible patterns for designing row houses found in every North American city. Montreal’s triplexes, New York’s Brownstones, Philadelphia’s rows are just three examples of how stacking floors around flight of stairs can become a centerpiece of urbanity. 

 

Typically, three or four floor arrangements are inset between party walls built along property lines to keep fire from spreading among juxtaposed units. These extending firewalls came to represent fireproofing requirements applied to medieval cities. The width of a standard city lot by a variable depth, spaces like living rooms and bedrooms are placed on either side of core spaces to benefit from natural light. The dual-exposed living areas contribute to a feeling of spatial opulence in an otherwise slim floor plate.  A multiple-floor sequence could be managed to suit multiple tenure scenarios: owner-occupied on all floors, one or two floors rented out as flats, and these even changing over time.  Seen as a prototype for efficient urban living, the townhouse has also been the subject of many research experiments. 

 

The Grow Home and The Next Home developed by Professor Avi Friedman from McGill University in the 1990s made the case for a standardized affordability through the demonstration of a type of row Core-houseadapting over time according to occupant needs. Each townhouse could suit the functional requirements of one to three households or even be divided to include a commercial or home office space on the ground floor. The Grow Home proposed a shell for owners to outfit as needed and as their potential to earn increased taking Habraken’s idea of supports and infill to the townhouse as a way of creating dynamic streetscapes from ordinary housing archetypes.

The American House-Carpenter «town house»

Prefabrication experiments - 420 - ML(row houses) - Weir Multicom panelized houses

The private villa set in a bucolic environment is a characteristic form of housing. Repeating this idealized model in large tracts gave shape to the garden city and suburbanization. The semi-detached house presents a different land allocation vision through pooling service distribution and sharing a demising wall.  Applying this principle in a row of attached units gives us the basis of efficient, structured urbanity. Cities are ordered by unit juxtaposition (single or multi-unit) that fashion the ubiquitous streetscape of dwellings that condenses infrastructure for roads, services and other amenities.

 

The row house / workshop unit is perhaps the most symbolic representation of urban housing; A ground floor relates to street circulation for shops, commercial spaces, or owner-occupied workshops. Upper floors, the piani nobili for living spaces, elevate private spaces above street level. These levels could be owner-occupied or rented out as flats. Its adaptability to multiple tenure or rental scenarios makes terrace housing one of the more flexible urban strategies. Characterized by a formal front elevation that relates to the street, an informal rear elevation that relates to a backyard, aligned in a series, and positioned back-to-back, the arrangement conveys the typical city block.

 

Spanning party walls, façades can be customized with canopies or ornamental details that identify entrances.  These are further personalized using materials, colors and geometries to achieve a dynamic composition from a basic configuration.  From the iconic Alvaro Siza’s (SAAL) social housing project to Alejandro Aravena’s manifesto at Quinta Monroy, the repetition of this model also showcases the row housing’s potential to rationalize costs along with decisions about design and construction: systems, pieces, components can be mass produced.

 

Many lightweight prefabrication systems have been adapted to the row house as they deploy a structured platform of construction principles, repeating dimensions and serial organizations. Industrialized systems like the postwar British Weir Multicom system epitomizes the baseline components that make the pattern so cost effective: Wall panels for partitions, exterior walls, doors, and all other building elements are used by many aligned dwellings and structured by a rhythmical party wall arrangement.

The Weir Multicom System (from semi-detached to row houses)