The Wärtsilä Sustainable Technology Hub features a prefabricated wooden element roof supplied by LapWall, combined with a steel frame. Building services penetrations and acoustic panels on the underside of the roof elements were installed at the factory. The rapidly installed roof solution eliminated the need for separate temporary weather protection during construction. Attaching the roof elements to the steel structure from above also meant that installation work did not interfere with other construction activities inside the building.
“Our delivery for Wärtsilä included roof element design and the associated structural calculations, as well as manufacturing and installation. A total of 606 roof elements were used to cover approximately 29,700 square metres,” explains Marko Kellberg, Business Director at LapWall.
“Like all our projects, this solution was tailored to the customer's needs. What all our deliveries have in common is that they include detailed element design and result in a watertight roof immediately after our installation work is completed. This eliminates the need for separate temporary weather protection during construction, resulting in significant cost savings,” Kellberg explains.
According to Kellberg, LapWall's insulated roof elements are suitable for all types of structural frames, whether concrete, steel or wood. He believes that the use of wooden elements will continue to increase as hybrid construction becomes more common and demands for construction quality and cost efficiency grow.
Combining a wooden roof with a steel-framed building is an extremely straightforward way to construct a roof. LapWall's solutions are also thoroughly tested, with careful design ensuring that potential risks are addressed in advance.
“First, we determine the element layout, then dimension the trusses and identify the connection points. The steel frame has steel fixing plates to which the roof elements are attached from outside the building. This means we do not need to work inside the hall, allowing other construction activities to proceed more efficiently. If a different roofing solution had been used in the Wärtsilä project, the work would have been much more complicated and time-consuming,” Kellberg explains.
“The load-bearing structure of the roof elements consists of LVL beams. The roofing material can be either a bitumen roofing membrane or a single-ply PVC membrane. The elements can be fully insulated or partially insulated,” explains Riku Bomberg, Design Manager at LapWall.
When a bitumen roofing membrane is selected, the underlay membrane is installed at the factory, where the seams are carefully sealed and inspected. The top layer is then installed on site.
The necessary building services penetrations are prepared at the factory. The roof membrane protects the prepared openings until the building services installers complete the penetrations.
“Roof drains are also installed at the factory, and the elements are manufactured with the necessary counter-slopes to direct water towards the drains. These solutions ensure that water can be effectively drained from the roof immediately after installation,” says Marko Kellberg.
In addition to the roofing membrane, thermal insulation and the underside lining are installed at the factory. The underside can be finished with coated plasterboard, acoustic panels or vapour-tight, polyester-coated sheet steel. The sheet steel solution is particularly suitable for buildings requiring high standards of hygiene and moisture resistance.
“Finishing the underside of the elements at the factory produces a neater result than completing the work on site. The roof can also accommodate suspended building services installations, with the necessary connection details already designed,” Kellberg explains.
“One distinctive feature of the Wärtsilä project was the use of white acoustic panels on the underside of the roof elements in the industrial areas. The acoustic surface helped reduce reverberation in these spaces. The solution was developed in collaboration with A-Insinöörit, responsible for structural design, and the main contractor, Luja. This saved the customer both time and costs, as there was no need to install the underside lining separately after the roof was completed,” explains Riku Bomberg.
“Problems must be resolved during the design phase so that there is no need to work out construction details on site. This is how we achieve a better end result,” says Marko Kellberg.
“We have numerous reference projects similar to Wärtsilä Sustainable Technology Hub, including industrial buildings, swimming pools and ice arenas, where we have worked together with other project partners to develop the most cost-effective roofing solution.”