Prefabrication experiments - 122 - material innovations - 3 - Patch22: a timber open building

Engineered timber, glue laminated and cross-laminated timber is propelling a resurgence in wood construction methods particularly in midrise collective and public housing. Considered for too long as a handicap, timbers’ performance specifically in terms of fire resistance is now being reconsidered and timber hybrids are being put forward in many buildings as an equivalent to reinforced concrete. Post and beam or wall and panel systems are comparable to slab buildings designed with spans of seven to nine meters. Patch 22, erected in Amsterdam, is a remarkable collective housing block showcasing this new potential for engineered timber for posts, beams, walls and trusses. The design also demonstrates timbers’ agility in matters of floor heights, spans and lean construction based on pre-cut components. Designed by the principal partner of principal of Frantzen and associates, an Eindoven graduate, Tom Frantzen, the proposal is suggestive of open building theory exploring planning flexibility, time adaptability and user personalization.

The architects and city planners formulated a mixed-use zoning ordinance to allow commercial as well as residential use in the same floor area. An apartment loft space could evolve over time in order to adapt to changing lifestyle, inhabitants or a different function. The planning flexibility and agility is articulated to the building’s rational use of timber, a generic floor plan, four-meter floor-to-floor heights and a hollow service floor. The void between the flooring and the structural floor panels generates a potential unrestricted distribution and conversion of mechanical systems, without disturbing adjacent or stacked units. 

The building’s timber framework is constructed with glue-laminated posts and beams and cross-laminated «hyperplywood» floor panels. The timber members are oversized to reach a three-hour fire rating. This overdesign of structural members is established on a burn-time-thickness ratio. When wood is charred it slows the oxygenation process, which decelerates the fire's progression. The burn time ratio is then converted into member thickness. Along with the obvious advantages of timber construction (beauty, carbon sequestration, renewable resource) the architects used both surface and filigree construction to express timber’s prefabrication heritage. The building also incorporates many other sustainable building technologies from rainwater harvesting to solar roof panels.

Patch22 - Amsterdam - section and axonometric views

Prefabrication experiments - 121 - material innovations - 2 - Fiberglass service pods by Charlotte Perriand

Technical advances between 1850 and 1950 brought an array of services to buildings. Sanitation and comfort were increased by electricity, plumbing, heating and air conditioning. Conveying air, water and power shaped a regulated interior environment while inducing a systemic entanglement of wires, pipes and ducts with traditional architectural schemes.  Various strategies such as plumbing walls, service core walls bathroom or kitchen pods or HVAC pods emerged as integrated solutions to reduce on-site coordination by standardizing services.

During the latter half of the 20th century advances in fiberglass technology united with a willingness to standardize machine like baths, kitchens and services. Technical hubs could by delivered and deployed into any construction system. Among the diverse pitches by architects, designers and manufacturers, Charlotte Perriand proposed fiberglass moulded bath capsules for the "Les Arcs" ski resorts in Savoy France. Perhaps, a result of her time spent working with and learning from Le Corbusier, the pods, were inspired by the efficiencies of ship building: Programmatic repetition made their production cost effective and their overall systemic coordination straightforward. They were in a sense machines for hygiene.

Fiberglass or glass fibre reinforced resin polymers were the choice materials for the ready-made pods as they could be produced in any shape and their moulds could be reused. A gelcoat base primer allows the plastic shape to be removed from the mould and produces a polished surface. Fiberglass is a thin layer of reinforcing glass fibre mesh encased in a polyester resin. The fiberglass could be used as a single layer or as a structural laminated sandwich panel with an expanding foam insulation core.

Today, bathroom pods produced by numerous companies are integrated into building types requiring repetitive service elements such as hotels or hospitals. Today’s pods however are overwhelmingly produced in traditional construction materials indicating that mainstream construction and architectural design lacked a sustained innovation of plastics as a substantial building material. The prefabricated pods rationalize initial construction but the relatively short service life of bathrooms and kitchens in buildings can quickly render the pods obsolete. Furthermore, the proprietary nature of these sub-components has proven to makes changes or replacement difficult over time. 

Prefabricated fiberglass bathroom pod (source: to be determined)