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The "Natural House", is a private family house which aims to inspire potential homebuilders to use more sustainable materials and methods to gain a modern, attractive and healthy home. It will function as a residential house for PermaLot staff, allowing the visitors to visualise "their" house, also through a number of interactive displays, integrated monitors (if funded) as well as information material of available suppliers. „The Natural House" is especially unique, due to the fact that it is first time a building permit was obtained for building a typical strawbale house in Czech Republic: With only a 3 cm earthern plaster securing min 90 minimum fire prevention.
Unlike several prestige low-energy projects, the Natural House is designed as low energy house, also in choice of using predominantly local materials with minimum embodied energy, saving the environment for pollution from production and transport of high energy materials. This also supports the local and national economy, while reducing CO2 emissions. We welcome you (with appointment) for a tour at our building site; The construction is not supported by any grants, and thus progress is slow and steady. We hope to have the new roof + ground level ready during summer of 2009.
Following the principle "No house is an island", the garden has been designed as a demonstration of permaculture vegetable garden/orchard and illustrate various ways of natural flood control, including several natural ponds and swales. The intire centre has the objective of being Czech Republic's Eastern demonstration site of natural building techniques and applied alternative energy in family housing situations: A very shining example for the public, managed by a public NGO. A high degree of local materials is used for the construction as the project especially focuses on the issue of embodied energy, hence adhering to the EU recommendations of "expansion through sustainable renovation of the existing building mass".
„The Natural House" is open for visitors every 1st weekend of the month from 10-17.
Guided tours for groups on other days possible with prior arrangements.
Set of performance indicators
1. 50% energy savings in comparison to present old farm buildings in Czech Republic.
2. 100% energy savings in the barn compared to the previous stage
3. 100% renewable energy for heating; natural cooling.
4. 75% of all construction materials from within a 50 km radius; 50% from within a 15 km radius.
5. To utilize the construction process for vocational training and research; to gain inclusion of construction with straw bales in the Czech building codes, as in neighbouring countries.
6. To integrate flood control, minimal waste and ensure local employment during construction.
7. To have maximum user satisfaction with the building, in addition to respecting surrounding environment
Innovative in planning and architecture: The architectural design responds to seasonal comfort requirements and contributes significantly to the reduction of energy costs. The orientation and passive design of the building will contribute to control of seasonal variation of the building bioclimatic conditions.
The "Natural House" integrates the following elements:
1. Insulation with straw bales on North, West and part of East sides, as well as in the entire roof.
2. Insulation of South and lower East side with Reed mats,
3. Plastering with local natural plaster (Partly as vocational training project),
4. Interior walls of recycled earth bricks, wattle and daub: Upstairs of compressed straw panels, ceilings earth plastered
5. Lumber from the adjacent forest (Part of it cut in accordance with moon-phase, in cooperation with Swiss research project),
6. Doors, windows and woodwork either re-used or made by local craft people,
7. Well-insulated and heat absorbing earthen floors used throughout the base floor; wall heating on second floor,
8. Roof made of burned tiles, with integrated rainwater catchment.
1. A centrally placed Finnish mass oven is capable of providing the majority of the heat for the Natural House while assuring minimal wood consumption at record low level emission of particles. A watercoil is integrated in order to heat distant rooms.
2. 8 Solar collectors ensures hot water during the warm season, and initial heat for the remaining centre during the winter.
3. Floor and Wall heating: the downstairs floor and upstairs natural plaster walls will have heating integrated; at areas exposed for demonstration purposes.
4. Passive Solar heating: The south side features a large trombe wall, as well as a large glass section by the kitchen: earthen walls within the trombe wall and interior floors will absorb the low winter sun; during summer it is shaded by the roof overhang.
5. The Natural house will be equipped with both 12 and 220 volt systems.
In addition, the Natural House will utilize extensive rainwater catchment /reuse, modern compost toilets, energy and water saving appliances.
Brief explanations of various building details:
Yes, not everything is natural in "the Natural House". We had to deal with the 110-year-old rock pillars, that were leaning each their way. In addition we did not want to fight with the old-fashioned Czech Building law. The result is a 1-meter x 40 cm concrete foundation, however made of 90% recycled old concrete blocks and field stones. The foundation on the uphill side of the house is hydro-protected with black bubble plastic. No plastic is used on the downhill sides, allowing any ground water to drain away naturally. Due to our intentions of creating a low-energy house, we chose to use extruded styrofoam around the foundation. It goes 120 cm deep and around 30 cm above grade, ensuring that there is no cold bridge to the rock pillars.
The floor was dug down to 40 cm below final floor level. A layer of sand was spread, which protects about 2000 four liter glass jars from local school kitchens. The jars prevent groundwater from rising and create a closed 24 cm isolative room under the floor. Atop the jars we placed 10cm styrofoam, made at a factory 7 km away. The styrofoam spreads the weight evenly on the jars and prevents the heat from the floor heat in radiating downwards. The final floor will be made from a mixture of earth, clay, sand and linseed oil, leveled and compressed, creating a beautiful modern floor, which easily can be washed and has excellent heat absorbing qualities.
The upstairs floor will be made from wood parquet of beech and oak, gained for free through demolition job from a PermaLot member (from authentic Bata house!) and family. The parquet floors will also be treated with our homegrown hemp oil and beeswax
You'll find the 40 cm thick strawbale walls on the West and Northern side, as well as in the eves of the Eastern side. Due to thickness we chose to mount a total of 20 cm reed mats on the Southern and lower Eastern side. All walls are plastered with min. 3 cm earthen plaster, made from our soil with added sand. For demonstration purposes we use some final commercial plasters of various colors and producers.
Interior walls are made from either unburned earthbricks, woven willow covered with earth or 'Ekodesky Stramit'; panels made of highly compressed straw.
The windows are either modern low energy windows with argon, or Danish 100 year old 2 layer farmhouse windows, as tests has proven that the old knowledge and quality is superior to most modern vacuum windows. The Southern side features a special 'trombe wall'; a glass covered black-painted wall: The sunlight heats up the 10 cm space between the window and wall throughout the day, with the earth bricks absorbing the heat. During evening we'll open 4 ventilation holes on top and bottom, allowing the trapped heat to circulate into the living area.
The roof is constructed with 2 individual roof trusses, allowing for strawbales to be used for insulation. The interior ceiling is earth plastered for looks and anti-fire/ moisture barrier, and on top of the strawbales a layer of clayplaster will be spread as fire prevention and moisture control. We save on the 'real' roof on the Southern side by covering a large area with solar collectors which are integrated in the roof. The optimal natural non-burnable roof cover would have been Czech made slate tiles, however we are only able to afford 'beaver' burned tiles.
Low energy living:
The house will be equipped with both 12 and 240 volt: Most appliances will run on 12 volt. All appliances will be chosen due to energy performance. A natural cooled cold box will be integrated in the kitchen counter and no refrigerator installed. Likewise no TV, though the living room will feature a digital projector and surround sound system