Student flats Virkakatu 8

The basic idea behind the conversion and renovation of the Virkakatu student flats was to improve the appearance of the building and cut energy consumption. The aim was to spread the word about energy efficiency and ecology.

The goal of the design was to renovate the early-eighties, low-rise block using the TES system (Timber-based Element System) and convert it into a passive, low-en­ergy building for use as student flats.

In order to improve energy efficiency, the form of the building was simplified at the re-entrant stairwells. The build­ing was clad on three sides with black, corrugated fibre-cement sheeting, while the principal elevation and the balconies were given a more colourful treatment. The new balconies were constructed inside the line of the black outer skin, while the elevation was sup­plemented with new canopies over the entrances to the staircases.

The individual flats were all given a thorough renovation. The kitchens were converted into kitchen-living rooms and a sauna was installed in each flat. Apartment sizes, room areas and par­ticularly bedrooms were all adjusted to meet the needs of families with children.

Structural alterations

The building was originally of concrete cross-wall construction. The concrete ground slab was demolished to improve moisture resistance and heat insulation, and to make the building weath­er-tight. This made it easier to renew the services.

The minimal dimensions of the roof space did not permit the installation of additional thermal insulation there, so the decision was taken to renew the roof construction. This meant that the roof could be made completely water-tight while ensuring adequate thermal insulation and ventilation of the construction. The original balconies were demolished and replaced by larger ones and exces­sive solar gain was cut down by using large overhangs.

The TES system

It was decided to demolish the outer brick-tile skin of the exter­nal-wall elements and the layer of mineral-wool insulation beneath it. Prior to installing the TES elements, a 50-mm layer of cementi­tious insulation was laid on the outer surface of the inner skin in order to level the surface of the concrete elements.

The external walls were carefully measured inside and out, be­fore the timber elements were manufactured, to take into account the necessary tolerances which were fairly generous for both the new timber elements and the openings in them.

The facade panels were installed in situ. Because of the thick­ness of the TES elements, the thickness of the plinth was increased all round the building. At the same time, proper ground drainage was installed and the ground levels around the building were ad­justed as necessary.

Services and energy efficiency

Devices to keep track of energy consumption and the condition of the construction were installed in the building. Sensors were in­stalled in the TES elements on all four elevations to measure build­ing physics performance in real time. This provides information for the research project and for the property management side.

Each flat has its own ventilation system and the building fulfils the requirements set by VTT for passive buildings.

This building is one of seven European pilot projects in the international E2ReBuild project. The project has been funded by the European Union Seventh Framework Programme.