Building Finland's Tallest Timber Building

JOENSUU Lighthouse is a new tall timber structure in the eastern Finnish town of Joensuu.

The structure, which features concrete foundations and a concrete ground floor, is otherwise fully built using engineered timber.

Standing 48 metres and 14 storeys tall, it is also the tallest timber building in Finland and contains 117 studios for local students.

Although a concrete core was initially proposed, it was rejected by the contractor who wanted a more environmentally friendly structure.

Above: Joensuu Lighthouse is the tallest timber structure in Finland (image courtesy of Arcadia Architects).

The walls of the building are made of laminated veneer lumber (LVL) - thin wooden sheets, rather than cross-laminated timber (CLT) which uses solid wooden planks pressed and glued together to form large panels.

CLT was used to form the building’s floors.

Above: The building's ground floor and foundations are made of concrete, the rest is all timber (image courtesy of Karelia-amk Karelia UAS).

The building relies on engineered timber to provide load-bearing capacity while its stability is ensured by steel rods that are used as bracing. Inside, the walls are lined with plasterboard.

Above: The project had to pass additional safety requirements (image courtesy of Joensuu).

With Finnish fire regulations only accounting for timber buildings up to 8 storeys, Joensuu Lighthouse was subjected to much more rigorous checks and inspections.

In addition to passive fire protection (plasterboard and wood charring), the building also features sprinklers throughout.