The Sustainable Low-tech Building

Edeltraud Haselsteiner

The goal of sustainable construction is to implement a mutually balanced combination of ecological, economic and social sustainability and insure its continuation over the entire life cycle of the building. To this end, sustainable low-tech building concepts question the use particularly of information and communications technology (ICT) and building automation systems as a long-term best approach to sustainable construction.

System limits and the role of technology in the life cycle

Though ICT systems offer options for building optimisation, their “intelligence” lies in carefully thought-out design. In his book Low-Tech Light-Tech High-Tech. Bauen in der Informationsgesellschaft (Building in the Information Society), Klaus Daniels provides the first comprehensive look at the entry of information technology into the building sector in the German-speaking sphere, an important milestone in the development of so-called “smart” building technology:

“Intelligently designed and operated buildings, often falsely referred to as “smart buildings”, are characterised not only by their highly interconnected information, communications and building automation systems, but primarily by the fact that they are capable of serving user needs directly from the environment, bypassing the utilisation of technical installations.” [1] In order to be able to not only maintain, but properly use buildings throughout their entire lifetime requires a well thoughtout and forward-looking design concept. Energy efficiency during operations should be valued just as highly as the consumption of embodied energy or the recyclability of materials. The same is true for sustainable low-tech buildings. The overarching question is, of course, what temporal or spatial dimensions define the limits of “low tech”. In concrete terms, it must be clarified whether the technology input should only be included when it can be directly connected to the construction, operation or deconstruction of the building, or whether the technological component of the manufacture of the building materials and parts should also be considered. One can also differentiate between assessments in the temporal dimension, along life cycle phases, or in the spatial, according to distance from the building.

The life cycle is roughly subdivided into four phases: Design and manufacture (raw materials) – assembly, construction and renovation – use, operation and maintenance – deconstruction and disposal. Different life cycle phases require different forms of technological input (Fig. 2). In the operations phase, a look at the technological contributions can be further simplified by considering the spatial distance to the building [2]: materials from the original industrial building and materials from buildings destroyed in the war. An additional goal of the renovation was to create a renewed awareness of recycling and reuse.

• Technology directly in or on the building or plot (heating, ventilation system, collectors, etc.)

• Amount of neighbourhood technology required for the building (energy distributor, water and sewer connections, etc.)

• Amount of municipal /urban technology required for the building (energy supply, waste disposal and recycling, etc.)

• Amount of supra-regional technology required for the building (extraction of energy source material, etc.)

Technological contributions during the design and in material/commodity production

According to the estimates of international experts, the share of global emissions due to information and communications technologies (ICT) now lies in the 2.1– 3.9 % range [3]. The upper limit of this estimate for the carbon footprint of computers, servers and the Internet thereby exceeds the 3 % contribution (as of 2018) to global greenhouse gas emissions of planetwide air traffic. In addition, the energy consumption of ICT grows by 9 % annually [4]. In the absence of targeted regulatory measures, ICT emissions will rise. Nevertheless, the direct and indirect environmental impact of the increasing use of digital media is being constantly underestimated.

2 Life cycle phases and technology used (examples)

Design and Manufacture

With regard to the comparability and ecological balance assessment, and also as a starting point for design decisions, however, this spatial categorisation provides little relevant information. For the following investigation of low-tech concepts, therefore, a material-related approach has been chosen. Significant technological contributions are those that can be proportionately attributed to a building and are either generated in the building itself or in its immediate surroundings in connection with its construction, use or deconstruction throughout its entire life cycle.

For the past few decades, digital technologies have played an important role throughout building planning. All design processes are now carried out with the help of CAD programs, various design software tools and electronic aids. In the past years, the use of building simulations to estimate the thermal-energetic behaviour of a building and the utilisation of Building Information Modelling (BIM) has also increasingly become the norm.

A considerable technological contribution is therefore already generated in the conceptual and design phases. The extraction of raw materials, material manufacture and transport account for further sizeable inputs due to technology. The criteria of

Assembly, construction, renovationUse, operation and maintenance

Design: ITMachines for excavation and site preparation

Technology used in extraction of raw materials

Technology used in construction, assembly and installations

Deconstruction and disposal

Technology used to produce building materials and components

Transport of commodities and materials

Technology used to renovate the building structure

Transport of people, building materials and components

Technology linked to building use

Equipment and components used in building operations, control and regulation (heating, cooling, ventilation, lighting, etc.)

Equipment and components used for upkeep and maintenance

Transport of people and goods for operations, upkeep and maintenance

Deconstruction planning / organisation

Technology used in deconstruction and disposal

Technology employed in reutilisation, recycling, reuse, etc.

Transport of waste, materials and components

The term “low tech” in architecture is currently not precisely defined. Rather, it signals a reassessment of the assumption that technology represents a cure-all for society, and expresses an experimentation with other options through greater utilisation of nature-based solutions, the use of natural materials and a preference for analogue processes. However, this is less a complete rejection of technology per se or of its evaluation in and of itself, and more about a holistic consideration of complete systems with regard to the goals of regenerative sustainability.

Regenerative sustainability aspires to the creation of auto-regenerating social and ecological systems. In this sense, natureand biology-based solutions, local environmental resources as well as social and cultural potential represent the weightbearing pillars of an integrated low-tech overall concept. The three aspects of sustainability – ecology, economy and social concerns – form the framework. However, since regional building traditions require more personal responsibility and activity on the one hand, and represent multiple fundamental building blocks of low-tech building concepts on the other, an expansion of the framework to include what scientific-political discourse dubs the fourth pillar (the “cultural” or “political-procedural” component of “institutions”, that is to say, “participation”) is essential [9]. Figure 4 gives an overview of examples of low-tech options that could make contributions toward the achievement of sustainability goals.

Low-tech architecture aims to maximise the use of local resources, natural elements and active principles in order to avoid the excessive consumption of energy and resources. The critical stance towards implemented technology is intended to scrutinise its effective contributions to the overall system and, with a view to the entire life cycle, demand more efficiency, social acceptance and health and well-being. Therefore, based on the four sustainability aspects, sustainable low-tech design can be characterised by the following basic design strategies:

• Ecology = a climate and resourceonserving building method that broadly employs available environmental conditions (climate, location and origin) for its operations and makes significant contributions to the regeneration of the ecosystem

• Economy = a sufficient, robust and costeffective building method that targets a reduced technological footprint throughout the whole life cycle (production –operation – deconstruction)

• Social concerns = a needs-based and socially equitable building method that provides for an agreeable level of comfort, provisioning and waste removal while simultaneously eliminating potential for harm and competition with others for food for this and future generations

• Participation / culture = a simple, understandable, locally proven building method based on personal responsibility, which promotes self-build construction, DIY maintenance and upkeep and the regional building culture

Aspects and possible impact levels of low tech (examples)

A Ecological quality ECOSYSTEM — climate, regeneration, resilience RESOURCES — form, energy, recycling systems

B Economic quality

ROBUSTNESS — life cycle costs, homogeneity, quality SIMPLICITY — functionality, maintenance, servicing

C Social quality

SUFFICIENCY — minimisation of requirements, area consumption, intensity of use HEALTH — natural commodities, material, relationship between humans and nature

D Participation / process quality

RECYCLABILITY — flexibility of use, deconstruction, documentation RESPONSIBILITY — adaptation to climate change, (building) culture, equity

Low-tech matrix

In the following sections, these individual facets will be examined in greater detail and explained by way of a comprehensive low-tech matrix (Fig. 5 and Fig. 8, p. 30f.).

Location, climate and ecosystem

Low-tech design strategies take a sitespecific approach. In this approach, local environmental resources are chosen as the means or catalysts of an energy-efficient and ecological initial design. For example, depending on the site, wind, sun, soil or water could represent the resources driving a holistic approach to a supply and waste removal solution, or locally available building materials could form the foundation for the basic design of the building. In contrast to technology-driven concepts, which tend towards a broad compartmentalisation against environmental influences that are unstable or hard to calculate in order to ensure that comfort standards remain constant, low-tech concepts rely on sufficiency and resilience. The goal is to make use of the dynamic ecological unity formed by people, building, location, nature and ecosystem and to develop optimised concepts based on it.

Robustness and resource conservation

High-quality building standards and construction details based on structures of proven craftsmanship are guarantors of robustness and a long (service) life. Beyond this, carefully thought-out and scrupulously executed structural details can reduce the use of technologically costly building equip- ment. Among the central goals are a sufficient and resource-conserving use of primary materials and the avoidance of emissions in all life cycle phases. This includes avoiding transport routes as well as doing without large-scale earth-moving and excavation. Additional characteristics of a low-tech design concept are material homogeneity, measures taken to reduce complexity in building details and the conscious decision to allow for “ageing” such as the greying of facades, as long as there are no associated impairments to the structure.

Energy and supply

Low-tech design relies on harnessing simple active principles and employing natural renewable environmental resources to supply buildings efficiently and based on a sufficient use of technology. An (energy-) efficient building method and an energetically optimised form create the starting point for as low a demand as possible for additional energy in the operations phase. Site-specific factors such as microclimate and topography join regionally available energy and environmental potentials (sun, earth, groundwater, wind, internal heat sources, seasonal and daily rhythms, etc.) as well as the efficient use of natural material and primary resource characteristics to form the supporting pillars of an energy concept based on low tech. In addition, it is important to harmonise eventual supply and removal cycles in the building with those of the surrounding buildings and the location (exhaust heat – heating / cooling, combined