Foto: Vojta Herout, www.nafotime.cz
Environmental Education Centre Na Pasece in Velíková
At the beginning, there were children happily playing in the woods. When a suitable building plot was found in Zlín, Tomáš Černý, a local parent, decided to build a complex that would serve for environmental education, as well as a background for the local forest kindergarten. This was exactly what was missing there. At the end, there is a construction of a straw bale house made of local materials with a green roof. Local craftsmen worked on the project. The premises are now used for community gatherings, environmental education programmes for schools and the kitchen can offer meals to alternative schools, as well as the public.
The Adaptation Journey
The positive impact
The straw bale house serves as an environmental education centre for schools and the public. All age groups can learn about the concept of natural building. The added value is the local origin of the materials used and the involvement of local craftsmen. The environmental education centre also serves as a reference for the work of these craftsmen for potential investors. It can thus help to popularize natural building in the Zlín region.
How does it work?
Local and recyclable
The aim was to use fully recyclable material from local sources for the construction of the centre. Straw bales, which were fixed into a wooden structure, were used to build the perimeter walls and to insulate the roof. The wood used was felled at a certain time during the lunar phase, when the trees would draw water into their roots. As a result, this so-called moon wood cracks less and is more resistant to pests.
Clay plaster on the interiors and limestone plaster on the exterior makes diffuse moisture exchange possible, thus maintaining a pleasant climate in the house. The massive perimeter walls made of straw bales also help maintain a constant internal temperature.
The stones used in the retaining walls and pavements comes from the nearby Bzová quarry.
The green roofs, that protect all the buildings of the centre (except the Yurt) cover an area of 239 square meters, significantly affecting the local microclimate. This is because there is no accumulation and radiation of heat like there is with common roofing materials. In light rain, the water soaks into the absorption layer and then evaporates into the air through plants, so it does not drain into the sewer without being used.
Green roofs provide food and refuge for insects, are an additional source of food for the local birds, and thus increase the biodiversity in the area. When the stonecrops are in blossom (there are 7 species of stonecrops on the buildings), the roofs are full of bees from a nearby apiary.
Biosolar green roof
In addition, the green roof on the main building is combined with solar panels, which is a mutually beneficial solution. The shade provided by the solar panels can create a pleasant microclimate for the growth of more shade tolerant species, prevent excessive roof drying and thus promote even greater biodiversity. This is because a mosaic of habitats is being created, which allows a wider range of plant species to blossom and attract various species of insects and birds.
The so-called biosolar green roofs are also beneficial for the operation of the solar panels themselves. Evaporation from the vegetation cools their lower part and thus increases their efficiency. This leads to higher electricity production. If the air around the panels is too hot, the panels may not work effectively. Green roofs help keep the temperature around the panels at around 25 ° C and this is ideal for solar energy production.
Every raindrop counts
The rainwater is collected into an underground tank with a volume of 8 m3 and is mainly used to irrigate gardens and lawns. A gravel and grass lawn is created on the surfaces around the buildings. Although the surface is paved, it allows efficient infiltration of rainwater.
Electricity made by the solar panels serves as an additional source of electricity to the sockets of the house, with any excess being used in the storage tank to warm the water. The main source of heat for both the hot water and the heating is a gasifying wood stove, which is connected to two 1 m3 storage tanks of hot water, one used for heating and one for hot water. A small wood burning stove in the dining room on the first floor is used for additional heating between cold seasons.
The whole building, therefore, is an almost self-sufficient house with sustainable energy sources, which also meets the low-energy standard criteria.
In the past, there was an old orchard on the plot, which later turned into a rather unmaintained meadow. Thanks to this, some of the original old varieties of fruit trees have been preserved, and wild flowers occur here naturally. This plot of land was maintained as a building plot in the cadastre of the village, so a traditional new house would have probably been built here.
Operation and maintenance
The building materials used are not yet common, so information about their maintenance will have to be learned during use. It is already clear where the weaknesses are. For example, clay plaster is prone to scratches and any subsequent repair is not easy. It is not possible to use ordinary blue sticky tack on them, for example, during seminars, so more durable glass surfaces had to be installed.
The maintenance and cleaning of wooden floors comes with the need to use special products for wood. A combination of larch and fir wood was chosen for better durability.
The maintenance of the area also includes the care of an adjacent garden with fruit bushes, trees, wild flowers and playground equipment for children. Compliance with legislation in this area means regular inspections, water analysis and other check-ups.
Obstacles and challenges
The study of natural building methods and the subsequent experience gained directly from natural builders on the construction site was a big challenge.
A construction of a straw bale house was something new for the Zlín Building Office. This made the preparatory part of the project take longer in order to clarify all the details.
During the construction, the location of the house on the lower part of a slope and the subsequent earthworks and construction work proved to be a problem. Analysis of the water from the well showed an increased content of iron and manganese, which is common in the given locality. Within three years, the composition of the water should become normal thanks to regular consumption.
So far, the biggest risk seems to be the faster wear and tear of natural materials due to weather as well as use.
Operation and maintenance
The very stable indoor climate in the building is a pleasant surprise. The insulating properties of straw really correspond to the available data.
The forest kindergarten is already operating in the centre, but the space was only open for visitors in September 2021, so it is still early to judge the operation. However, a detailed two-year-long collection of data is planned. Subsequently, a detailed analysis of this project will be prepared and made available for similar projects.
The project won first place in the Green Roof of the Year 2021 competition in the Public Extensive Green Roof category.
How much did it cost?
The costs were estimated at 11 million crowns.
The investor's own resources were used.
The return on the project is assumed to be 30 years, the lifespan is calculated at 100 years. The savings were not calculated.
Public buildings Use of rainwater Heating Green roof Biodiversity Heat waves and thermal island Green energy Energy savings