Efficient and fast process

Elementit-E prefabricates wooden modules in its own factory in Kouvola and takes care of the on-site erection of the buildings. On the assembly line, the various elements for schools are assembled, resulting in “mega-modules”, which range from 60 to 80 m2 in size.

The production timetable for Kartano and Helilä Schools was really fast, because it takes only about one day to finish a new module – a classroom, for example. The biggest modules were 6.6 x 10–12 metres.

“Kerto LVL is a great match for modern module production. We receive the dimensionally stable S-beams at the assembly line from Metsä Wood in the right sizes at the right time,” says Hyyryläinen.

The modules are assembled at a factory, which is a safe environment with dry and predictable conditions. The prepared modules for Kartano School in Järvenpää and Helilä School in Kotka were weather-protected with plastic. To avoid traffic, the modules were loaded in the afternoons and transported to the building sites during the evening and at night.

Frame with prefabricated LVL beams

The load-bearing structure consists of various Kerto LVL S-beam applications. The internal walls include diagonal support, and S-beams are glued and screwed together to stiffen and stabilise the buildings.

“The rigid structure transfers the loads to the foundation,” says Hyyryläinen.

The floors consist of Kerto LVL S-beams with customised product dimensions in the frame, combined with a honeycomb structure. The floor has an insulation layer between the beams, and the panel is on top. In the upper floors, the lighting, air conditioning and acoustic systems are connected to the beams. The unique structure allows floors with a long open span.

Highly fire-resistant

The structures of both two-storey schools were planned and built in accordance with fire safety regulations. Both Kartano and Helilä schools were built in accordance with the P2 fire class, with no need for sprinklers.

Fire resistance is 30 minutes for the Kerto LVL S-beams used in the roof. In the walls, the S-beams have been covered with gypsum board or plywood, and floors have a stone wool layer, which protects the S-beams from fire from above.

Long-term cooperation

Hyyryläinen is satisfied with the cooperation with Metsä Wood, which has lasted for a long time. The most important factor is the quality of Kerto LVL.

“Consistent quality is important, because it ensures that our production runs well. We’ve also developed things with Metsä Wood that are beneficial for everyone. They’ve also started to produce Kerto LVL blockings between the floor joists in floors and intermediate floors, and we can focus solely on the assembly part,” Hyyryläinen says.