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VTT: Improving energy efficiency is revolutionizing building in Finland

15.03.2011

Moisture damage risks of zero-energy buildings can be avoided

The EU’s Energy Performance of Buildings Directive is revolutionising construction Europe-wide. As a Member State, Finland, too, is committed to reducing its building stock CO2 emissions.

“Today’s new builds will be outdated in less than ten years. Despite vast improvements in the quality of construction work, mistakes are still rife. We need to raise the quality bar, and soon, because ever-increasing renovation of our old building stock is something we simply can’t afford,” explains energy efficient construction expert Jyri Nieminen from VTT Technical Research Centre of Finland. 

The energy objectives of low-, passive- or zero-energy buildings can only be achieved if the necessary design and construction quality are up to scratch. This will also go a long way towards soundly eliminating the quality defects typically responsible for moisture damage.

Responsibility for preventing moisture damage lies both with the client and the construction and maintenance service providers. The appointment of adequately skilled designers and contractors and effective supervision of the interests of the client are the client's own responsibility. Clear objectives based on performance must be set for the building, and these must be verifiable at the commissioning stage.

Moisture damage in buildings has traditionally been caused by leaking piping systems and substandard work quality. Rainwater penetration into structures is a classic sign of poor quality facade construction, or a simple lack of proper maintenance. Other common causes of moisture damage include inadequate or flawed waterproofing, incorrect storage of construction materials, and carelessness and negligence during construction or maintenance. 

Energy efficient construction costs in Finland are 2–7% higher than conventional construction based on current regulations. For example, the costs of a multi-storey passive building constructed for TA Asumisoikeus Oy in Oulu, Finland, were 3.3% higher than those of an adjacent conventional apartment building of similar layout and design. Renewable energy installations are a key source of extra costs in zero-energy buildings.

Reducing the energy demand of buildings is one of the most effective means at our disposal for mitigating climate change. The smaller the building’s energy demand, the easier it is to meet with the building’s own building integrated energy production.

Finland has leading know-how in this field, for example in the thermal insulation of buildings, and energy-efficient building services installations and window technology. To promote the export of this expertise, working examples of Finnish solutions need to be constructed. The results of Finnish research into energy efficient buildings have been successfully utilised by turning developed building and energy technologies into competitive assets for Finnish companies.

VTT has been researching and developing zero-energy construction technologies since 1990. The focus of this development work has been on solutions that provide high energy efficiency and good indoor climate without compromising on design or usability. Some of the key problem areas in low-energy construction have been identified and resolved, for instance, with the help of sensors installed in pilot buildings. 

What is a zero-energy building?

A zero-energy building or, more specifically, ‘net zero energy building’, produces at least as much useable renewable energy as it uses from conventional energy sources. Similarly, a nearly zero-energy building meets at a significant proportion of its energy needs with renewable energy that is produced either by the building itself or by a renewable energy facility located nearby – as is the case with renewables-based district heating.

Zero energy and zero emissions buildings are currently the focus of intense global interest. The Norwegian University of Science and Technology NTNU, for example, is developing leading solutions for zeroing the carbon dioxide emissions of buildings.

Commercial applications for zero-energy buildings have been developed around the world. Finland's first, and the Nordic countries’ leading example of a near zero-energy high rise apartment building was completed in Kuopio at the end of 2010. Another is to be built in Järvenpää this year. In addition, zero-energy single-family houses are also being built and developed in Finland.

Finland’s IEA5 house, built in Pietarsaari in 1993–1994, is, according to the EU’s Energy Performance of Buildings Directive, a near zero-energy building. The house has been performing smoothly and greenly for more than 17 years.