In 2012, residential buildings accounted for 20% of Finland’s total energy consumption. As efforts are being made to reduce energy consumption in all areas of life, including construction and housing, modern construction has faced entirely new challenges. Efforts are being made to make new buildings increasingly energy-efficient, meaning that traditional methods that have been in use for hundreds of years no longer work on their own.
In this blog post, I’ll discuss the importance of structural integrity from the perspective of log homes, but the same principles largely apply to other types of buildings as well.
Functional structure
Housing standards are significantly higher today than in the past, and the inclusion of washrooms and saunas in residential buildings can put the moisture-related performance of the building’s structures to the test. For this reason, it is particularly important to prevent moist air from inside the house from escaping into the building’s structures, where it can condense and cause moisture damage.
In a modern log house, air does not flow through the structure, but the solid log structure safely absorbs heat and moisture and releases them as external conditions change. As a result, conditions inside the building remain stable—just like in a traditional log home, but without the drafts that compromise living comfort and energy efficiency.
Low energy consumption
Heating energy consumption has been reduced by, among other things, increasing the thickness of insulation layers. The thin insulation layers of the past were relatively warm throughout and therefore dried out quickly due to the heat. A well-insulating layer is warm on the inside but cool on the outside. The downside of good insulation is the loss of the drying effect of heat. For this reason, a modern energy-efficient structure must be airtight to prevent moisture from entering.
Energy is also saved by recovering the thermal energy from the exhaust air blown out of the house. For this reason, both supply and exhaust air must be routed through the ventilation unit. Controlled ventilation is only possible in an airtight house where there are no uncontrolled air leaks through the building envelope. It is also important to remember to perform the necessary maintenance on the ventilation unit and replace the filters.
Cozy and healthy
Air leaks in a building’s exterior envelope cool the interior surfaces and cause drafts that reduce living comfort. Drafts can occur, for example, around windows and doors, at the junction of the floor and ceiling, and through electrical outlets. In a well-sealed house, there are no unpleasant drafts.
In an airtight house, the indoor air is cleaner. Because ventilation creates a slight negative pressure in the building, outdoor air flows through the structure into the room. An airtight building envelope ensures that contaminants—such as those from the soil or air that has passed through building materials—do not enter the indoor air.
How tight should it be?
Airtight construction isn’t rocket science; with careful and precise work, it’s easy to achieve a high level of airtightness. Sealing individual penetrations is important, but large structural assemblies have the greatest impact on airtightness. For this reason, it is worth focusing on the airtightness of joints such as those between the floor and wall, and between the roof and wall.
Everyone involved in the construction process should be informed that the goal is to create an airtight building and that they are expected to carefully seal any holes they make in the building envelope and report them to the contractor.
The log house kit comes with sealing instructions from the manufacturer. It is advisable to review these instructions before starting construction to ensure that the sealing is done correctly and at the right stage of the project. When sealing, it is important to keep the entire life cycle of the house in mind. Seals should remain effective for at least 50–100 years.
A modern, compact house
- A modern log structure helps regulate fluctuations in humidity and temperature, but air does not circulate through the structure
- Low heating costs
- Comfortable living conditions
- Air leakage rate q50 = 0.6
- Annual heating energy lost through leaks = 430 kWh
- Cost of energy waste = €50 per year
An old house with natural ventilation
- The structure buffers fluctuations in humidity and temperature, and air flows through it in both directions
- High energy consumption
- Uneven living conditions
- Air leakage rate q50 = 10
- Annual heating energy lost through leaks = 7,200 kWh
- Cost of energy waste = €790 per year
A modern house,
which has airtightness issues
- The structure is not functioning as intended
- Rising heating costs
- Declining quality of life
- Air leakage rate q50 = 4
- Annual heating energy lost through leaks = 2,900 kWh
- Cost of energy waste = €320 per year
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