The SINERGO houses are designed according to the passive house standards with the thermal energy consumption for heating of up to 15 kWh/m² per year; therefore, increased attention is paid to the thermal properties of the building envelope, which are three to four times higher than required by LBN002-01 ”Thermotechnics of Building Envelopes”.
In order to achieve the energy savings goals, a building envelope with a high thermal insulation coefficient is used in the project.
The choice of the building envelope heat transfer U values and the overall microclimate of the building according to the passive house construction requirements is based on the calculations of a certified passive house designer.
To ensure the required airtightness, special sealing materials (adhesive tapes and polyurethane seals) are used to seal all construction joints and utility outlets in the building envelope.
The materials used in the construction of the exterior walls – cellulose insulation and wood fibre boards – ensure high thermal resistance and significantly increase the thermal inertia of the construction element. Cellulose heat insulation and wood fibre boards are derived from wood; therefore, the exterior walls have the thermal inertia characteristic to wooden structures, which is an important advantage in the changeable Latvian weather conditions both during the heating period and in the hot season. Increased thermal inertia of the construction element serves as an additional thermal battery, absorbing daily temperature fluctuations and reducing the heat gained through exterior walls on hot summer days.
The construction of the exterior walls is made of wood-frame I-beams. Cellulose heat insulation has been filled between the I-beam struts of the frame, and on the outside the wall has been additionally insulated using ecological wood-fibre boards, ensuring high thermal resistance. Wall panels are designed to avoid the so-called thermal bridges, while the assembly technology allows obtainment of a high-quality structure with very tight joints.
SINERGO houses are equipped with PassivHaus certified windows with triple pane glazing and improved solar gain. The window installation method has been chosen to maximally reduce the thermal bridge effect. All windows are designed to be placed in the insulation layer in such a way as to obtain a thermal bridge value Ψ of not more than 0.01 W/m²K.
Industrially manufactured load-bearing trusses with a 2-degree roof slope, filled with 600-mm-thick cellulose insulation. The overhang part of the roof structure includes a rain gutter.
The roof design is suitable for Latvian weather. The permissible snow loading of up to 300 kg/m² (3 kN) is two to three times higher than the minimum requirements of the Latvian construction norms.
The floor structure is made of wooden frame floor panels. The structure consists of load-bearing 350-mm I-beams filled with a 350-mm insulation layer and covered with OSB-3 of 22-mm thickness on both sides.
To make sure the house still looks great in 10 years, the facade uses the highest-quality decorative granite plaster and thermal wood decoration boards treated with natural linseed oil stain made by THERMORY.
The longevity of the thermal wood is achieved through heat treatment by treating the wood with high temperature and steam, making the wood resistant to rot, protecting it from discolouration, torsion, damage, moisture absorption, spread and shrinkage.