Stadthaus
Encyclopedia
Stadthaus is a nine-storey residential building in Hackney, London. It is thought to be the tallest timber residential structure in the world. It was designed in collaboration between architect
s Thistleton, structural engineer
s Techniker, and timber
panel manufacturer KLH.
Stadthaus is the first high-density housing building to be built from pre-fabricated cross-laminated timber panels. It is the first building in the world of this height to construct not only load-bearing walls and floor slabs but also stair and lift cores entirely from timber.
of architecture
. In the endeavour to build buildings that reduce the impact on the planet, the Practice see it as vital not only to consider the energy usage over the life of the building but also the energy expended in producing the building. For some years Waugh Thistleton have been researching the use of solid timber structures in housing
to replace the accepted route of concrete
and steel
.
Timber stores 0.8t of carbon dioxide within 1 cubic metre and is a replenishable material. In comparison the production of both concrete
and steel
are one-way energy intensive processes that release large amounts of carbon dioxide
into the atmosphere. The panels can also be easily demounted and used as an energy source at the end of the building’s life. So the case for timber was made to the client and London Borough of Hackney's planning department both in terms of the environmental consideration and potential economies to cost and programme.
s for the building’s approval were clearly defined. The site area is 17m x 17m and bound on all sides by other residential buildings. An extrusion
of the site area set the building’s plan form and the height at nine storeys was set as a maximum, before overshadowing would become an issue.
The Housing Association
Metropolitan Housing Trust required that a separate ground floor entrance be provided for the affordable units. This resulted in a mirrored floor plan from east to west, with an identical entrance to each aspect. Both tenures are served by an individual staircase and lift. The five upper storeys are designated for private sale and the three lower storeys for social housing. The majority of social housing is made up of family apartments which overlook the play area to the rear of the building.
Telford Homes specifically required that the interiors were consistent with a standard developer specification, which means that inside the apartment
s feel completely conventional, belying the revolutionary nature of their structure.
by KLH using Spruce
planks glued together with a non-toxic adhesive
. The waste timber is converted to fuel
powering both the factory and local village. Each panel is prefabricated including cut-outs for windows and doors and routed service channels. As the panels arrived on site they were immediately craned into position and fixed in place. Four carpenters assembled the eight-storey structure in twenty-seven days. The speed of the construction
in such a densely populated environment is especially relevant, as was the lack of noise and waste, creating far less intrusion on the local community than a traditional concrete frame construction.
A ‘platform construction’ configuration is used throughout this structure. Each floor is set on the walls below, and then another storey of walls is raised and so on up the building. Joints are secured with screws and angle plate
s. Stresses are generally very low throughout the structure and at points where cross-grain pressures are high, screws have been added to reinforce the timber locally. Progressive collapse
is avoided by providing sufficient redundancy
so that any single elements can be removed. Designing a building constructed from load bearing panels creates a number of opportunities. Any internal wall can become a party wall and have a significant portion removed from the surface area as openings. This simple flexibility allowed for different plan types up and down the building and an animated façade where windows were placed according to the best advantage.
Typically a new technology in construction provides a reduced volume of building material
; lighter weights produce cheaper faster buildings. The impression of solidity once inside this building is evident, the interior spaces and the acoustic they give off affirm a sense of place and home.
Traditional trades and methods followed on once the structure of each floor was complete. The enthusiasm of the work force for the construction and the ease of the build was a benefit beyond anticipation. The building was completed in 49 weeks, estimated to be a saving of five months over a notional concrete frame construction and occupied ahead of programme in January 2009.
of the building in three ways. Firstly, the production of cement produces 870 kg of carbon dioxide. This equates to 237 kg of carbon per tonne. The project's sustainability
expert estimates that if this building were to be a concrete structure, it would contain approximately 950 cubic metres of concrete. This would require 285 tonnes of cement and would, therefore, produce approximately 67,500 kg of carbon.
Additionally, the production of steel produces 1750 kg of carbon dioxide, which is 477 kg of carbon per tonne. It is estimated that the building would, if built in reinforced concrete
, require about 120 tonnes of steel, the production of which would have generated 57,250 kg of carbon.
901 cubic metres of timber have been used within the building. Timber absorbs carbon throughout its natural life and continues to store that carbon when cut. The fabric of Stadthaus stores over 186,000 kg of carbon. Thus, the chosen construction method has resulted in a reduction in the carbon load of the building of 67,500 + 57,250 + 186,000 = 310,750 kg of carbon. This is equivalent to over 310 tonnes of carbon. The estimated carbon dioxide produced in the generation of the energy for the building, including the transportation of the timber panels from Austria, is 10,000 kg/c/yr. This has been entirely offset by the building’s carbon saving for some 21 years.
and fire protection
. Timber buildings are classified as poor in terms of their acoustic performance due to the light structure as compared to reinforced concrete and masonry. However, cross-laminated solid timber panels have a significantly higher density than timber frame
buildings. They provide a solid structural core on which different, independent and separating layers can be added. The layer principal overcomes any acoustic or sound transfer issues. In Stadthaus an economic layering strategy of stud walls, floating floor build-ups and suspended ceilings, gave sound attenuation far in excess of building regulations (58 - 60db).
In a fire, a solid wall of timber benefits from the protection of a charred layer and therefore does not combust in the same way as a single stud. In Stadthaus, five-layer cross-laminated timber panels are used to obtain a fire protection that allows the structure to retain its integrity for at least 90 minutes. This is significantly longer than steel, which fails and buckles at high temperatures. The 90 minutes at Stadthaus have been achieved with the plasterboard finish – two layers of plasterboard provide 60 minutes with the final 30 minutes achieved by the calculation of charring rate of the KLH solid timber panels. Calculations by the project engineers however show that in fact the KLH panels comfortably achieve a 60 minute fire resistance period with the panel thicknesses used for this project so the design team has been slightly modest.
Regulations in Europe have meant there are no precedents for Stadthaus. However, architectural and engineering
methods in timber construction pioneered by Waugh Thistleton and Techniker are now accepted internationally. By gaining the necessary certificates from both NHBC and Building Research Establishment
, both of which treated Stadthaus as a pilot scheme, the design team considers that timber panels are the building material of an environmentally conscious future.
Architect
An architect is a person trained in the planning, design and oversight of the construction of buildings. To practice architecture means to offer or render services in connection with the design and construction of a building, or group of buildings and the space within the site surrounding the...
s Thistleton, structural engineer
Structural engineer
Structural engineers analyze, design, plan, and research structural components and structural systems to achieve design goals and ensure the safety and comfort of users or occupants...
s Techniker, and timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...
panel manufacturer KLH.
Stadthaus is the first high-density housing building to be built from pre-fabricated cross-laminated timber panels. It is the first building in the world of this height to construct not only load-bearing walls and floor slabs but also stair and lift cores entirely from timber.
Ecological aspects
Waugh Thistleton are committed to reducing the environmental impactEnvironmental degradation
Environmental degradation is the deterioration of the environment through depletion of resources such as air, water and soil; the destruction of ecosystems and the extinction of wildlife...
of architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...
. In the endeavour to build buildings that reduce the impact on the planet, the Practice see it as vital not only to consider the energy usage over the life of the building but also the energy expended in producing the building. For some years Waugh Thistleton have been researching the use of solid timber structures in housing
House
A house is a building or structure that has the ability to be occupied for dwelling by human beings or other creatures. The term house includes many kinds of different dwellings ranging from rudimentary huts of nomadic tribes to free standing individual structures...
to replace the accepted route of concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
and steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
.
Timber stores 0.8t of carbon dioxide within 1 cubic metre and is a replenishable material. In comparison the production of both concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
and steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
are one-way energy intensive processes that release large amounts of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
into the atmosphere. The panels can also be easily demounted and used as an energy source at the end of the building’s life. So the case for timber was made to the client and London Borough of Hackney's planning department both in terms of the environmental consideration and potential economies to cost and programme.
Design approach
The form of the design was predetermined by a number of factors. Previous architects had received two planning refusals on the site and as a result the acceptable parameterParameter
Parameter from Ancient Greek παρά also “para” meaning “beside, subsidiary” and μέτρον also “metron” meaning “measure”, can be interpreted in mathematics, logic, linguistics, environmental science and other disciplines....
s for the building’s approval were clearly defined. The site area is 17m x 17m and bound on all sides by other residential buildings. An extrusion
Extrusion
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...
of the site area set the building’s plan form and the height at nine storeys was set as a maximum, before overshadowing would become an issue.
The Housing Association
Housing association
Housing associations in the United Kingdom are independent not-for-profit bodies that provide low-cost "social housing" for people in housing need. Any trading surplus is used to maintain existing homes and to help finance new ones...
Metropolitan Housing Trust required that a separate ground floor entrance be provided for the affordable units. This resulted in a mirrored floor plan from east to west, with an identical entrance to each aspect. Both tenures are served by an individual staircase and lift. The five upper storeys are designated for private sale and the three lower storeys for social housing. The majority of social housing is made up of family apartments which overlook the play area to the rear of the building.
Telford Homes specifically required that the interiors were consistent with a standard developer specification, which means that inside the apartment
Apartment
An apartment or flat is a self-contained housing unit that occupies only part of a building...
s feel completely conventional, belying the revolutionary nature of their structure.
Construction method
The building was assembled using a structural cross-laminated timber panel system. The timber panels are produced in AustriaAustria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
by KLH using Spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
planks glued together with a non-toxic adhesive
Adhesive
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...
. The waste timber is converted to fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
powering both the factory and local village. Each panel is prefabricated including cut-outs for windows and doors and routed service channels. As the panels arrived on site they were immediately craned into position and fixed in place. Four carpenters assembled the eight-storey structure in twenty-seven days. The speed of the construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
in such a densely populated environment is especially relevant, as was the lack of noise and waste, creating far less intrusion on the local community than a traditional concrete frame construction.
A ‘platform construction’ configuration is used throughout this structure. Each floor is set on the walls below, and then another storey of walls is raised and so on up the building. Joints are secured with screws and angle plate
Angle plate
An angle plate is a work holding device used as a fixture in metalworking.The angle plate is made from high quality material that has been stabilized to prevent further movement or distortion...
s. Stresses are generally very low throughout the structure and at points where cross-grain pressures are high, screws have been added to reinforce the timber locally. Progressive collapse
Progressive collapse
A building undergoes progressive collapse when a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failure, similar to a house of cards....
is avoided by providing sufficient redundancy
Redundancy (engineering)
In engineering, redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe....
so that any single elements can be removed. Designing a building constructed from load bearing panels creates a number of opportunities. Any internal wall can become a party wall and have a significant portion removed from the surface area as openings. This simple flexibility allowed for different plan types up and down the building and an animated façade where windows were placed according to the best advantage.
Typically a new technology in construction provides a reduced volume of building material
Building material
Building material is any material which is used for a construction purpose. Many naturally occurring substances, such as clay, sand, wood and rocks, even twigs and leaves have been used to construct buildings. Apart from naturally occurring materials, many man-made products are in use, some more...
; lighter weights produce cheaper faster buildings. The impression of solidity once inside this building is evident, the interior spaces and the acoustic they give off affirm a sense of place and home.
Traditional trades and methods followed on once the structure of each floor was complete. The enthusiasm of the work force for the construction and the ease of the build was a benefit beyond anticipation. The building was completed in 49 weeks, estimated to be a saving of five months over a notional concrete frame construction and occupied ahead of programme in January 2009.
Sustainability
Using a bulk timber panel system affects the carbon footprintCarbon footprint
A carbon footprint has historically been defined as "the total set of greenhouse gas emissions caused by an organization, event, product or person.". However, calculating a carbon footprint which conforms to this definition is often impracticable due to the large amount of data required, which is...
of the building in three ways. Firstly, the production of cement produces 870 kg of carbon dioxide. This equates to 237 kg of carbon per tonne. The project's sustainability
Sustainability
Sustainability is the capacity to endure. For humans, sustainability is the long-term maintenance of well being, which has environmental, economic, and social dimensions, and encompasses the concept of union, an interdependent relationship and mutual responsible position with all living and non...
expert estimates that if this building were to be a concrete structure, it would contain approximately 950 cubic metres of concrete. This would require 285 tonnes of cement and would, therefore, produce approximately 67,500 kg of carbon.
Additionally, the production of steel produces 1750 kg of carbon dioxide, which is 477 kg of carbon per tonne. It is estimated that the building would, if built in reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...
, require about 120 tonnes of steel, the production of which would have generated 57,250 kg of carbon.
901 cubic metres of timber have been used within the building. Timber absorbs carbon throughout its natural life and continues to store that carbon when cut. The fabric of Stadthaus stores over 186,000 kg of carbon. Thus, the chosen construction method has resulted in a reduction in the carbon load of the building of 67,500 + 57,250 + 186,000 = 310,750 kg of carbon. This is equivalent to over 310 tonnes of carbon. The estimated carbon dioxide produced in the generation of the energy for the building, including the transportation of the timber panels from Austria, is 10,000 kg/c/yr. This has been entirely offset by the building’s carbon saving for some 21 years.
Building high in timber
Concerns associated with timber buildings are predominantly related to acousticsAcoustics
Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics...
and fire protection
Fire protection
Fire protection is the study and practice of mitigating the unwanted effects of fires. It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies, as well as the research and development, production, testing and application of...
. Timber buildings are classified as poor in terms of their acoustic performance due to the light structure as compared to reinforced concrete and masonry. However, cross-laminated solid timber panels have a significantly higher density than timber frame
Timber framing
Timber framing , or half-timbering, also called in North America "post-and-beam" construction, is the method of creating structures using heavy squared off and carefully fitted and joined timbers with joints secured by large wooden pegs . It is commonplace in large barns...
buildings. They provide a solid structural core on which different, independent and separating layers can be added. The layer principal overcomes any acoustic or sound transfer issues. In Stadthaus an economic layering strategy of stud walls, floating floor build-ups and suspended ceilings, gave sound attenuation far in excess of building regulations (58 - 60db).
In a fire, a solid wall of timber benefits from the protection of a charred layer and therefore does not combust in the same way as a single stud. In Stadthaus, five-layer cross-laminated timber panels are used to obtain a fire protection that allows the structure to retain its integrity for at least 90 minutes. This is significantly longer than steel, which fails and buckles at high temperatures. The 90 minutes at Stadthaus have been achieved with the plasterboard finish – two layers of plasterboard provide 60 minutes with the final 30 minutes achieved by the calculation of charring rate of the KLH solid timber panels. Calculations by the project engineers however show that in fact the KLH panels comfortably achieve a 60 minute fire resistance period with the panel thicknesses used for this project so the design team has been slightly modest.
Regulations in Europe have meant there are no precedents for Stadthaus. However, architectural and engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
methods in timber construction pioneered by Waugh Thistleton and Techniker are now accepted internationally. By gaining the necessary certificates from both NHBC and Building Research Establishment
Building Research Establishment
The Building Research Establishment is a former UK government establishment that carries out research, consultancy and testing for the construction and built environment sectors in the United Kingdom...
, both of which treated Stadthaus as a pilot scheme, the design team considers that timber panels are the building material of an environmentally conscious future.
Further reading
- Henrietta Thompson (2009) "Stadthaus: A Process Revealed / Auf Dem Holzweg", FUEL ISBN 978-0-9558620-6-9
- Lynne Blundell: “Timber: complex, sustainable and good in bushfires“, The Fifth Estate, January 2010