Foundational principles for ecological construction
Ecology is the science of contexts and functions in nature (between living organisms and their environment) together with the internal relations between them. In this sense all houses are ecological. To what extent a house or a city is affected by a climate and becomes a part of a place and landscape or not is not a choice; that which architects can affect on the other hand is how these necessary relations come to be and which character they assume. A viable society must be built on biological processes and closed ecological cycles. This will require changes in overarching ways of thinking.
The idea of a house that has no effect on an environment at all is an illusion. All houses entail an environmental impact to some degree. The built environment constitutes a drastically modified habitat in comparison to the landscape’s original unbuilt state. Like a tree, a house alters the habitats about itself and imports and concentrates resources for a group of willful intentions. Concentration of these resources and the following outputs has many consequences. Harvesting and production of building materials at least entail changes to unbuilt places that often lie far away from the house. Even though a certain environmental impact follows all of humans’ acts of building, not all changes to habitats must be negative. Some houses have a substantially smaller environmental impact than others and contribute to regenerate the places about them, such that the aggregated effects of the building initiative are healing and invigorating when the whole is evaluated. It is possible to build in a regenerative way such that negative effects are compensated for by positive effects, such as with the creation of new habitats for other species in the garden, new supplies of energy and nutrients, no release of harmful synthetic substances, and establishing personal connections to a place. It is such intentions that lie behind ecological design and ecologically conscious building.
- Regeneration: Many existing initiatives in «green building» seek to achieve only reductions in environmental impact rather than net positive relations, and therefore they promote solutions that lead only to a less bad version of the existing built environment and that do not challenge the underlying irrationalities in conventional building methods. The existence of humans at a place does not necessarily entail negative consequences. The objective must rather be regeneration, where houses and cities contribute to establish and maintain productive ecosystems.
- Build robustly with ecologically defensible materials and building methods
- Build as little as possible: approximately half of energy use in a house is related to area and nearly the entire material and land use.
- Build flexibly and process-oriented with a life cycle perspective
Adaptation to place
- Building orientation in relation to compass directions and the sun has influence on temperature control, microclimate, wind directions, pressure conditions, risk of leaks, driving rain and moisture damage.
- Adapt to microclimate to reduce wear and energy use.
- Adapt to the site’s topography to reduce and ideally avoid entirely detonation.
- Protect existing vegetation to the greatest possible degree and connect the house to local plant societies.
- Research the site’s radon danger and other pollutants such as traffic noise, electrical lines etc.
- Build with comprehensive use of natural and relatively pure renewable materials, especially wood, brick, earth and clay.
- Build with biodegradable materials to the greatest possible extent.
- Hygroscopic materials regulate moisture in a passive way, and with the help of latent heat exchange they even out temperature loads.
- Design for re-use, re-cycling and recovery. Design for disassembly entails 1) to separate layers; 2) possibilities for disassembly within each layer; 3) use of standardised components that consist of only one material. Mechanical fasteners (e.g. screws) are preferred instead of glued and composite products.
- Use recycled products where it is possible.
- Use as little as possible products and building solutions that contain or require use of synthetic glues, paint, putty, impregnation methods or other synthetic chemicals. These products are often impossible to re-use or re-cycle and end up usually as harmful toxic waste.
Adaptability and maintenance
- Use timeless forms.
- Use simple plan solutions that are flexible and can easily be changed according to needs. Rooms with a size between 12 and 16 m2 can easily be adapted to many different activities over time.
- Initiatives that increase area efficiency:
- Use of common functions
- Double use of functions: colocation of related functions will normally reduce consumption of space considerably.
- Compression of functions
- Temperature-differentiated function distribution: by placing less heat-sensitive functions outside of the most resource-intensive climatised areas, it is possible to reduce a building’s environmental impact considerably.
- Reduced number of rooms
- Reduced corridor area
- Centrally placed entrance either from the outside, from a stair space or corridor will reduce communication areas, and in row houses access should be placed preferably on the back side.
- Use of otherwise unused spaces/volumes
- Optimalised placement of components and elements
- Increased roof height
- Use of views and opening of visual axes
- Conscious use of colour
- Build well insulated external constructions.
- Energy concepts can be based on combustion of renewable biomass in highly efficient stone masonry ovens or small pellet ovens in smaller homes.
- Conscious use of windows and other openings in the building envelope. Large glass surfaces make temperature control difficult and more resource intensive, and they entail an increased risk of overheating, increased radiation loss with following radiative asymmetry and higher air temperatures.
- Adapt the heating source to the heating requirement.
- Use of radiant heat can achieve thermal comfort with lower operative temperatures compared with other heating methods.
- Water-borne heating systems laid in sand or a wood fibre plate and covered with a brick or wood floor that can easily be disassembled and laid back again is an effective heating solution that is both energy-efficient and comfortable.
- Roof-mounted solar collectors can cover the majority of the requirement for hot water and space heating with a wood oven as a supplement.
- Plant societies become integrated with the home.
- Evaluate recovery of water and energy from used water
- Evaluate local treatment of greywater.
- Use of biological toilets produces no blackwater.
- Composting is a part of a connected garden.
- Reserve enough space for sorting of used items in the kitchen.
- The home together with the garden is designed as an ecosystem.
Avoid risk of moisture damage
- Prevent water from forcing itself into the building, amongst other things with conscious initiatives such as avoiding flat roofs and reducing penetrations and constructions on the roof.
- Reduce and avoid cold bridges as much as possible.
- Be especially careful with air-tightening of constructions during the building fase.
- Reduce the consequences of moisture by using mineral materials in moisture-exposed situations such as the bathroom, foundation against the ground, etc.
- Have sufficient moisture capacity to even out varying moisture loads throughout the day.
- Make conscious use of glass such that one avoids overheating of living rooms (when in use) and avoid disturbing radiation losses (radiation asymmetry).
- Secure good temperature control.
- Have sufficient heat capacity: Constructions can be pre-heated during the winter such that the air temperature when rooms are in use is held lower. The construction can also be used for passive cooling by exploiting low night temperatures.
- The house can be divided into several different thermal zones that receive their own regulated temperatures. Where the building is divided into thermal zones and the requirements for U-value and air tightness have been met, it should be possible to use lower set-point temperatures for heating.
- The building must be built as tight as possible. This gives better control over total air exchanges and reduces the risk of moisture damage as a consequence of condensation in constructions.
- It is an advantage to have an internal pressure deficit. This reduces further the risk of moisture damage as a consequence of condensation in constructions.
- Control intake air in relation to external temperatures. This gives automatic adaptation to the seasons.
- Natural ventilation encompasses all of the passive measures one can take to ventilate a home and reduce the requirement for ventilation at the point of departure - thermal capacity, moisture capacity, preconditioning outside, self-driven ventilation, etc. Often one will be able to meet requirements with only passive means, while other times one must supplement natural ventilation with active systems, fans, filters, etc.
- Natural ventilation solves many problems related to mechanical ventilation systems, harmful inner air and poor inner climate. Natural ventilation makes it possible to avoid using valuable electricity for fans, pumps and not least for cooling.
- Since the home is exposed to very different loads throughout the day and year, ventilation should be controlled by the ventilation need.
- Strengthened self-draught is self-driven ventilation where solar radiation strengthens the thermal driving forces. Wind can also be a driving force for natural ventilation because of pressure differences that it can create about a house. The house can be equipped in addition with propeller fans that start up when the self-driving force becomes too weak. Fans usually make possible better opportunities for cooling, since they can make use of cool nighttime air.
Generally good solutions
- Build for high technical durability. All cables and installations should be easily available for maintenance and upgrades. Electrical channels can be mounted in transverse cable paths with a screw lid.
- Room functions with high temperature requirements (kitchen, bathroom and living room) should be placed centrally in the house and be screened by bedrooms, gest rooms, storage rooms, etc.
- A cold food storage room on the north side reduces the need for a refrigerator.
- An individual drying room for herbs and clothes can be based on natural air circulation.