The designer of the built Passive House will consider! selection of the technology of erecting walls as a very important element of its structure in the overall energy balance of the building. As you know, construction block or the mineral wool used, do not have the adjective "passive" on their own. Properly used and built-in according to the design guidelines, they allow to obtain the heat transfer coefficient qualifying the partition for certification by the Passive House Building Institute.
When choosing the technology of erecting walls, the designer was guided by the following guidelines:
the material had to be available and known,
low risk of construction errors when installing into the partition,
possibility of masonry work at temperatures down to -5 ° C,
good (short) heat transfer coefficient,
due to the passive nature of the investment, it had to be a technology from the so-called. program (mortar, reinforcement and materials in the form of building-in tools),
smooth surface of the walls allowing the use of sealing compounds and facilitating finishing works,
the manufacturer's possession of training materials for contractors.
As you can see, the choice is not easy, most manufacturers of structural elements are eliminated due to the use of thick "traditional" mortars or the method of operation – "I will sell, I will bring, I'll drop and hello ". Canadian technologies face the barrier of low skills of contractors in Poland, and the construction of a passive house requires precision. Any neglect is a potential thermal bridge.
The designer selected the YTONG and SILKA technologies after getting to know the trends in passive construction in the world. In most of the constructed passive buildings in Europe, SILKA and YTONG blocks were used as structural elements. Around 20 % of the buildings, reinforced concrete poured in specialized formwork was used (very high cost of making the partition). YTONG and SILKA material is known in traditional and energy-saving construction, in fact, when used in a passive house, it will be an integral part of it. A bit of history and product data for people, who are unfamiliar with these technologies: YTONG aerated concrete was established in Sweden eighty years ago. As a completely natural and warm material, it is also light and easy to work with, has found wide application in Western countries – in both housing construction, and industrial. Today it is produced in thirty-one countries, including in Poland.
It consists mainly of natural resources: lime, sand and water. It is a material that is harmless to the environment. The concentration of natural radioactive elements in cellular concrete is lower than in other commonly used building materials, e.g. in ceramics.
It is produced in several varieties marked with symbols 700, 600, 500 the 400. These symbols indicate weight 1 m3 of aerated concrete. The lower the numeric symbol, the lighter the material – with a higher degree of loosening, and therefore with better thermal insulation. Of course, we used a variant of the material in the passive house 400.
YTONG elements are characterized by high dimensional accuracy and an even surface. This allows them to be combined with a thin layer (thickness 1 – 3 mm) system mortar, thus preventing the formation of thermal bridges on the joints.
Loosening of aerated concrete makes, that walls – both constructional, like cannons – have good heat capacity. This ensures a constant and pleasant microclimate inside the building.
YTONG and SILKA technologies. offer a full range of building materials, manufactured in the necessary strength classes. This allows them to be used in the entire building structure to make load-bearing walls, divisions, but also for the construction of lintels, ceilings and roofs.
YTONG elements can be easily cut to the desired dimensions, getting the shapes you need. They are easy to connect with a thin-layer masonry mortar. With a little care, you can get an even wall or other building surface – surface, on which plaster can be applied, stick plasterboard sheets, wallpaper or tiles. During bricklaying, slight lateral shifts of individual elements may occur. In such cases, it is enough to level the wall by grinding the surface briefly with coarse sandpaper. The resulting even wall is prepared for further finishing. Ease of processing aerated concrete, comparable to the treatment of wood or wood-based materials, makes, that it is very easy to arrange all kinds of installations and insert them into the wall. Even the grooves can be made with hand-held styluses. Holes, e.g. under installation boxes, is drilled with an ordinary electric drill with a special feather drill. The heat transfer coefficient obtained in the middle of the wall in the experimental Passive House is "perfect". This is the value of i 0,114 W/(m2 K), the standard for passive houses is 0,15 W/(m2 K), and the energy-saving standard 0,30 (W/m2 K).
Means, that parameters have been achieved that exceed the requirements for passive houses.