Evaluation of Building biology aspects for the three prototype houses.
Building biology, it is all about healthy buildings, natural living spaces. A living space low in risk factors, but promoting life, vitality, and regeneration.
In building biology, nature is our best guide, advocate, and resource. Once the natural balance is disturbed, it is foolish to believe that there would be no consequences over time. Life-threatening chaos always takes over when the fundamental harmony of the life-sustaining cosmos is out of balance. Any interference with natural processes results in disastrous consequences sooner or later, each and every time. Nature does not take revenge, nature responds bio…logically. Leave nature be! It cannot be improved. Creation does not need extra tutoring. Nature does not need us, but we do need nature.
When building homes not only functionality, sustainability, aesthetics and costs are important, but also the health and well-being of the future inhabitants, and those related to the construction, is of importance. At Sacred Groves we want to give these health related aspects a separate attention. After all our house is our third skin.
To check if all building biology parameters are taken into consideration the 25 principles of Building Biology as described by the IBN is the good tool to do so during the design and preparation stage. After completions actual measurement can take place in that case the guidelines of the SBM2015 are the one but best reference (nature is our best reference).
The construction of the prototypes is currently going on. Conducting measurements according the SBM 2105 are mostly premature, the results will not give a realistic picture. Therefor the 25 principles will be used as guideline as far as applicable, although in some cases it is somewhat late to start thinking about them.
Contents
Evaluation of Building biology aspects for the three prototype houses.
Building site:
1. Site buildings on land free from geological and human-made disturbances.
2. Locate residential homes away from pollutant and noise sources.
3. Provide low-density housing with sufficient green space.
4. Develop individualized housing and settlements in harmony with nature in ways that support human and family needs.
5. Building activities shall cause no social problems.
Building materials and noise control.
6. Use natural and unadulterated building materials.
7. A building shall have a pleasant or neutral smell, not releasing any toxins.
8. Use building materials with the lowest possible level of radioactivity.
9. Protective measures against noise and vibration pollution need to be based on human needs.
Indoor climate:
10. Regulate indoor air humidity naturally by using humidity-buffering materials.
11. The total moisture content of a new building shall be low and dry out quickly.
12. Strive for a well-balanced ratio between thermal insulation and heat retention.
13. Optimize indoor surface and air temperatures of a given space.
14. Promote good indoor air quality through natural ventilation.
15. Use radiant heat for heating.
16. Interfere as little as possible with the natural balance of nature’s own background radiation.
17. Prevent exposures to human-made sources of electromagnetic fields and radio-frequency radiation.
18. Minimize exposures to mold, bacteria, dust, and allergens.
The environment, energy, and water:
19. Minimize energy consumption while using renewable energy whenever possible.
20. Prefer regional building materials, not promoting the exploitation of scarce and hazardous resources.
21. Building activities shall cause no environmental problems.
22. Choose the best possible drinking water quality.
Interior design:
23. Take harmonic measures, proportions, and shapes into consideration.
24. Select light exposures, lighting systems, and colour schemes following natural conditions.
25. Base interior and furniture design on physiological and ergonomic findings.
Building site
1. Site buildings on land free from geological and human-made disturbances.
There are no indications of any human-made disturbances. Geological disturbances have not been tested.
2. Locate residential homes away from pollutant and noise sources.
The site is located well away of any source of pollution or noise. The only disturbing noise is the temple music of the neighboring village.
3. Provide low-density housing with sufficient green space.
At present this is not an issue. However Sacred Groves is part of the residential zone of Auroville. The future expansions surrounding will bring more houses in the neighborhood. This is one of the challenges of Sacred Groves to provide sufficient housing while maintaining enough green spaces and a healthy social life.
4. Develop individualized housing and settlements in harmony with nature in ways that support human and family needs.
A lot of thought has been given in how to promote a healthy social life. For Sacred Groves as a community we have chosen the co-housing model. Within Sacred Groves houses will be built in clusters with different levels of sharing. This should make it possible to include a large variety of people into Sacred Groves.
The three prototypes under construction are designed as one family house, a couple house and a single studio. Individual privacy is taken care of by common separation walls and a staggered lay-out, so that no window or door is facing another house. Common is a large central veranda leading to the entrance doors, this to promote shared activities. Further there are common facilities, such as services (power, water and waste water), washing machine, and sufficient space to develop more.
There will be plenty of green space around. On one side there is a six acre forest, and apart from common greenery each house has a small individual garden.
5. Building activities shall cause no social problems.
The work is being done by volunteers and interns from all over the world together with local craftsmen. To avoid that due to cultural differences conflicts occur we aim to establish a good relationship with the nearest village, in case of issues there are contact people from the village who can help in solving them.
Occasionally we make use of an earth moving machine, a waste cooking oil generator, and some use of power tools is also there, this will lead to noise. The closest neighbors are still at some distance but the noise will be heard, some understanding from both sides is the best solution.
Although not directly related to building activities, the young volunteers and interns can be noisy according Auroville neighbors. This needs to be dealt with in an adequate way.
Building materials and noise control:
6. Use natural and unadulterated building materials.
This is of no concern. One of the main targets of Sacred Groves is to put the standard for sustainable building as high as possible. Choosing natural and unadulterated building materials is the most logic step.
The primary building materials are Local available earth, straw, waste demolition rubble, quarry dust, Palmyra and coconut wood, lime, and reused Mangalore roof tiles.
Secondary building materials are: steel, bamboo, PE sheet, and bitumen sheet, waste petrol pipes (rubber and steel), OPC, glass …
Sacred Groves wants to up-cycle waste materials in the construction whenever possible, without having an unwanted impact on the quality of the indoor climate.
7. A building shall have a pleasant or neutral smell, not releasing any toxins.
This is of no concern. The materials used have a neutral smell. Keeping this in mind-some maintenance may be needed.
8. Use building materials with the lowest possible level of radioactivity.
Main building material is locally available earth, which has no influence on changing the natural background radioactivity.
The only suspicious building material is granite. The quarry dust, used as replacement for river sand, is a waste product from granite mines. In between testing during construction have indicated a slight increase of the natural background radioactivity, but still well within the limit of no concern according the SBM2015.
9. Protective measures against noise and vibration pollution need to be based on human needs.
Walls are built of 2 Feet thick cob. There is no contact as well as air propagated noise expected due to the building mass and the plasticity of the building material.
External influence of noise is currently not relevant, no windows are facing another house. This will become a point of attention when future clusters are going to be build.
Internal vibration from fans or other vibrating appliances need to be avoided by proper installation.
Indoor climate:
10. Regulate indoor air humidity naturally by using humidity-buffering materials.
The two feet thick cob walls with mud plaster take care of the humidity buffering very well. Walls should not be treated with none hygroscopic paints, lime wash is the best option, when needed.
11. The total moisture content of a new building shall be low and dry out quickly.
This may be a problem because of the two feet thick walls, however in our hot climate and the passive ventilation system there should be no reason for concern 1)
12. Strive for a well-balanced ratio between thermal insulation and heat retention.
Thermal insulation is not relevant since there is no active temperature control taking place. The thermal capacity of the walls take care of the buffering of the exterior temperature fluctuations.
13. Optimize indoor surface and air temperatures of a given space.
Not relevant, since there is no active temperature control, the surface and air temperatures will not deviate much, there is only the thermal lag.
14. Promote good indoor air quality through natural ventilation.
Ventilation is done by the principle of a solar chimney. The space under the tiled roof will be heated by the sun. Openings in the roof, either gable, ridge or ventilation-tiles will give the hot air the chance to be released from the building, creating an under pressure in the house. By controlling the air inlet by opening or closing windows a vertical ventilation will be created. Most windows are facing one side. On this side leafy plant and trees should be planted to create a natural cooling of the air this air will used to enter the building.
During the night or in times with little sun, low power inlet fans can be used to take over the ventilation.
Essential is not to create any short circuits in the airflow, design should be made in such a way that the air can flow freely throughout the whole building.
Users should be well instructed about this system.
15. Use radiant heat for heating.
In our case it is better to say using radiant coolness for cooling. The thermal capacity of the building mass should take care of this. However time will tell us how good this effect will be during the hottest part of the summer, when the temperature difference between day and night are little, due to high humidity and the average temperature will be high. On such an occasion the passive ventilation may become more important.
16. Interfere as little as possible with the natural balance of nature’s own background radiation.
The use of metals is limited to an absolute minimum. This will not disturb the geomagnetic field.1)There will be a solar power installation of which the currents may induce disturbances of the geomagnetic field, however by twisting the wiring and keeping distance from living areas, this disturbance will be minimal
The building mass is mainly of locally obtained subsoil, and is not expected to change other terrestrial radiation. Atmospheric and cosmic radiation will most likely be partly absorbed, but so will the man-made radiation, which turns it into an advantage.
Electrostatics will not be an issue because of the use of natural building materials. It may be introduced by occupants with synthetic fabrics and furniture, however the high humidity of our climate takes care of a fast discharge.
17. Prevent exposures to human-made sources of electromagnetic fields and radio-frequency radiation.
Several measures are taken reduce electromagnetic pollution as much as possible.
There will be two separate electrical installations. The main installation for all fixed appliances will be a 12 Volt direct current installation, electrostatics are negligible. This installation has no real issues, all loads are small. It would be good to twist the wires, and avoid loops in the wiring, to be free of magneto statics.
A 230 Volt will be there to provide power for the flexible appliances, for this the following actions need to be taken:
Low frequency electric fields coming from the installation are eliminated with the use of used petrol pipes as conduits for the electrical wiring. The shielding of these petrol pipes has proven to be successful against emitting LF electric fields, when properly grounded. Joining the steel shields with each other or other metals needs to be done in a way to avoid corrosion.
Low frequency magnetic fields are reduced by a radiant lay-out of the wiring, by twisting the life and neutral wires, and keeping distance from resting areas as much as possible.
The power inverter should provide a high quality sine-wave, to avoid net pollution. And located in a shielded well-grounded compartment, grounding the casing of the inverter might suffice (needs to be tested), to reduce the emission of radio frequencies generated by the power electronics.
There is no full shielding against radio frequency exposure coming from outside, however the building mass will absorb most of this radiation, and metal mosquito mesh will reflect this radiation from the windows. Radiation can enter easily through wooden doors and frames, and the tiled roof. However there are no public transmitters in the near vicinity. Any wild growth of antennas (including WIFI and point-to-point transmitters) in the future needs to be avoided, it is advised that issues should be discussed before implementing.
The use of transmitters inside the houses is being discouraged by locating sufficient outlets for internet and landline telephone. There will also be a special shielded cupboard near the entrance where cell phones can be stored and charged safely. For the remaining it will require organizational methods and goodwill of the users.
18. Minimize exposures to mold, bacteria, dust, and allergens
In a construction with natural building materials there is always a risk for these biological pollutants. To avoid them a good ventilation is needed, and avoid places with stagnant air.
The internal walls will have a mud plaster, with the final coat of mud plaster some cow dung needs to be mixed, this is a known antiseptic. In case the walls get no further treatment it is advised to apply a coat of diluted cow dung regularly. Best is to treat the wall with lime wash. Lime is alkaline and mold will not affect it. 1).
Exterior walls will treated with a lime plaster, no molds should grow there, only when dust is sticking to the walls molds may grow.
The woodwork is treated either with cashew oil or a borax/boric acid solution to prevent pests. All wood should be able to “breath”. In cases where it is not possible, the wood is protected with bitumen sheets wrapped with aluminum foil, to avoid rotting.
Measures against bacteria and yeast need to be done on a maintenance level by the users.
The environment, energy, and water:
19. Minimize energy consumption while using renewable energy whenever possible.
The power supply comes from solar. A diesel generator converted to run on waste cooking oil and a windmill can be used as back-up.
20. Prefer regional building materials, not promoting the exploitation of scarce and hazardous resources.
All primary building materials are locally and abundantly available.
21. Building activities shall cause no environmental problems.
Waste will be avoided as much as possible or of a composition that it can safely be returned to nature. Sacred Groves has a resource center, where usable waste can wait for a second life.
Occasionally diesel fueled power tools (like an earth moving machine are being used). The use of such tools should be reduced to an absolute minimum.
22. Choose the best possible drinking water quality.
Sacred Groves wants to be independent of water. Rainwater will be harvested to be used for domestic purposes. There will be a bore well as back-up. Drinking water needs to be purified. Several options are available this depends on the wishes of users and the quality of the water.
Interior design:
23. Take harmonic measures, proportions, and shapes into consideration.
The houses will be somewhat organically shaped, by eliminating any sharp corners. Sizes comply with the needs for feeling safe and comfortably, they give a spacious feeling but are not abundantly large.
24. Select light exposures, lighting systems, and colour schemes following natural conditions.
All main window openings are facing south, to avoid direct heating through the windows of the summer sun. While during the rest of the year the houses will benefit the light of the Southern sun.
Lighting system will be based on LED lights with a warm white colour.
Walls will get lime wash, white (to benefit the daylight) with some pigments added (to give the spaces a well-chosen atmosphere).
25. Base interior and furniture design on physiological and ergonomic findings.
In fixed furniture this will be taken into consideration, for the rest the occupants can be guided in the choice of furniture.