Shearing layers
Encyclopedia
Shearing layers is a concept coined by architect Frank Duffy
which was later elaborated by Stewart Brand
in his book How Buildings Learn: What Happens After They’re Built
(Brand, 1994), and refers to buildings as composed of several layers of change.
The layers are (quoted from Brand, 1994):
Site: This is the geographical setting, the urban location, and the legally defined lot, whose boundaries and context outlast generations of ephemeral buildings. "Site is eternal." Duffy agrees.
Structure: The foundation and load-bearing elements are perilous and expensive to change, so people don't. These are the building. Structural life ranges from thirty to three hundred years (but few buildings make it past sixty for other reasons).
Skin: Exterior surfaces now change every twenty years or so, to keep up with fashion or technology, or for wholesale repair. Recent focus on energy costs has led to re-engineered skins that are air-tight and better-insulated
.
Services: These are the working guts of a building: communications wiring, electrical wiring, plumbing
, fire sprinkler systems, HVAC
(heating, ventilating, and air conditioning), and moving parts like elevator
s and escalators. They wear out or obsolesce every seven to fifteen years. Many buildings are demolished early if their outdated systems are too deeply embedded to replace easily.
Space Plan: The Interior layout—where walls, ceilings, floors, and doors go. Turbulent commercial space can change every three years or so; exceptionally quiet homes might wait thirty years.
Stuff: Chairs, desks, phones, pictures; kitchen appliances, lamps, hairbrushes; all the things that twitch around daily to monthly. Furniture
is called mobilia in Italian
for good reason.
The concept of Shearing Layers leads to an architectural design principle, known as Pace-Layering, which arranges the layers to allow for maximum adaptability.
Frank Duffy (architect)
Francis Cuthbert "Frank" Duffy CBE is a British architect, a founder of DEGW, the international architectural and design practice best known for office design and workplace strategy and, more recently for advanced thinking on the programming of educational and arts facilities...
which was later elaborated by Stewart Brand
Stewart Brand
Stewart Brand is an American writer, best known as editor of the Whole Earth Catalog. He founded a number of organizations including The WELL, the Global Business Network, and the Long Now Foundation...
in his book How Buildings Learn: What Happens After They’re Built
How Buildings Learn
How Buildings Learn: What Happens After They’re Built is an illustrated book on the evolution of buildings and how buildings adapt to changing requirements over long periods. It was written by Stewart Brand and published by Viking Press in 1994...
(Brand, 1994), and refers to buildings as composed of several layers of change.
Description
The Shearing layers concept views buildings as a set of components that evolve in different timescales; Frank Duffy summarized this view in his phrase: “Our basic argument is that there isn't any such thing as a building. A building properly conceived is several layers of longevity of built components” (quoted in (Brand, 1994)).The layers are (quoted from Brand, 1994):
Site: This is the geographical setting, the urban location, and the legally defined lot, whose boundaries and context outlast generations of ephemeral buildings. "Site is eternal." Duffy agrees.
Structure: The foundation and load-bearing elements are perilous and expensive to change, so people don't. These are the building. Structural life ranges from thirty to three hundred years (but few buildings make it past sixty for other reasons).
Skin: Exterior surfaces now change every twenty years or so, to keep up with fashion or technology, or for wholesale repair. Recent focus on energy costs has led to re-engineered skins that are air-tight and better-insulated
Insulation
Insulation means:* Building insulation, added to buildings for comfort and energy efficiency* Soundproofing, also known as acoustic insulation, any means of reducing the intensity of sound...
.
Services: These are the working guts of a building: communications wiring, electrical wiring, plumbing
Plumbing
Plumbing is the system of pipes and drains installed in a building for the distribution of potable drinking water and the removal of waterborne wastes, and the skilled trade of working with pipes, tubing and plumbing fixtures in such systems. A plumber is someone who installs or repairs piping...
, fire sprinkler systems, HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...
(heating, ventilating, and air conditioning), and moving parts like elevator
Elevator
An elevator is a type of vertical transport equipment that efficiently moves people or goods between floors of a building, vessel or other structures...
s and escalators. They wear out or obsolesce every seven to fifteen years. Many buildings are demolished early if their outdated systems are too deeply embedded to replace easily.
Space Plan: The Interior layout—where walls, ceilings, floors, and doors go. Turbulent commercial space can change every three years or so; exceptionally quiet homes might wait thirty years.
Stuff: Chairs, desks, phones, pictures; kitchen appliances, lamps, hairbrushes; all the things that twitch around daily to monthly. Furniture
Furniture
Furniture is the mass noun for the movable objects intended to support various human activities such as seating and sleeping in beds, to hold objects at a convenient height for work using horizontal surfaces above the ground, or to store things...
is called mobilia in Italian
Italian language
Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...
for good reason.
Theoretical Base
The concept is based on the work of ecologists (O’Neill et al., 1985) and systems theorists (Salthe, 1993). The idea is that there are processes in nature, which operate in different timescales and as a result there is little or no exchange of energy/mass/information between them. Brand transferred this intuition to buildings and noticed that traditional buildings were able to adapt because they allowed “slippage” of layers: i.e. faster layers (services) were not obstructed by slower ones (structure).The concept of Shearing Layers leads to an architectural design principle, known as Pace-Layering, which arranges the layers to allow for maximum adaptability.