2.1.2 Pile foundation

same time maintain comfortable microclimate inside. The effectiveness of a passive house is based on the efficient thermal insulation and higher tightness of envelope components. A passive house is the concept (method) of construction applied in practice. A passive house is a standard widely used in constructing energy-saving buildings. A newly constructed passive house must save 80% of heat resources; otherwise it is not a passive house. The heating energy demand of a passive building is less than 15 k Wh/m2 per year. However, a passive house is something more than just an energy-saving house [5–9]. This concept involves sustainable, high-quality, valuable, healthy and durable construction. Features of a passive house are the following: high insulation of envelope components, high-quality windows, good tightness of the building, regenerative ventilation system and elimination of thermal bridges. The recommended architectural solutions are simple forms, less angles in order to avoid the development of thermal bridges at the joints. The most effective form of the house is the one with the smallest area of external walls. For these reasons it is easier to build a house of bigger floor area meeting the passive house criteria because the area of external wall and thermal bridges is smaller than the useful floor area of the building. A passive house should have no basement; otherwise the basement must be well insulated. Besides, it is recommended to plan as many windows on the southern façade in order to use more natural solar energy. Windows must be made of special frames filled with double-chamber selective glass units. The site also has a significant effect on the energy demand by the building. Shadows from the neighbouring buildings must be considered when building a house in the district where tall buildings prevail. Water may be heated by electricity; however solar panels are recommended. Combination solar wind power generation units are recommended to produce electricity for lighting and regenerative systems as well as for household needs [10, 11]. This article examines technological

and structural solutions for passive buildings' main structures.

2. Alternative solutions for passive house structures

Foundation is one of the most essential elements of a house. The type of foundation for a private house is selected considering many factors. The main factors are the type of the ground, groundwater level, frost line in the region, presence or absence of the basement, type of bearing walls, architectural decisions and financial resources. To choose the correct foundation type for the house, the builder must have the results of engineering and geological surveys, the final design of the

Strip is made of assembled concrete blocks or monolithic concrete. It is built under the bearing walls and partitions. This method requires land excavation, concrete element assembling and concrete pouring work. Construction of strip foundation is not cheap, but it is the most appropriate foundation for a house with a

Monolithic strip foundation provides a more rigid framework, but the installation is longer than the foundation made of assembled concrete blocks. Monolithic strip foundation is recommended when the house is built on expanding soil. Strip foundation is recommended when the house walls are made of heavier materials, for more than one-storey houses, and there is no need to build other types

2.1 Alternative solutions for foundation

building and calculations of loads.

2.1.1 Strip foundation

Zero and Net Zero Energy

basement.

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Pile foundation distributes the load of the building via pile cap and sides; therefore the stress propagates across the big volume of soil. Pile foundations do not sink much and have a high load-bearing capacity; thus they are suitable for buildings that are sensitive to subsidence.

As the piles are driven deep into the ground, it is impossible to fully insulate the entire foundation. Thermal bridges occur at the pole and grade beam joints, and they deteriorate the heat conservation capacity of the building.
