28.12.2015

Construction of Helsinki’s Wood City kicks off in the spring of 2016

Construction of Wood City in Jätkäsaari, Helsinki, is expected to begin in the spring of 2016. The site will include Finland’s tallest wood construction, a landmark 8-storey wood office building.

Windproof wood construction

For project architects and builders, Wood City’s seafront location has posed several challenges. To ensure the structural stability of Finland’s largest wooden quarter, engineers have had to take into account the site’s unique wind load. “Jätkäsaari is the windiest place in Helsinki, with rain often falling almost horizontally. We have worked extra hard to achieve effective moisture control and stability,” says Antti Vilén, Business Unit Director at Sweco and lead structural engineer for the Wood City project.

Glue-laminated solid wood elements will be used as external cladding in Wood City. These elements will also be pre-patinated grey, and alternate with glass elements in the final design. “We have tried to create modern, urban-inspired wood architecture, which combines both wood and glass elements. We are also making the most of the amazing seafront view and natural light. We want Wood City to convey the maritime history and spirit of Jätkäsaari,” says head architect Matti Huhtamies from Anttinen Oiva Architects.

Tallest wood office building

When planning the landmark office building, builders opted for a wood post-and-beam framing and cross-laminated timber (CLT) intermediate floors. The first floor and elevator shafts will be made of concrete. The concrete elevator shafts will improve overall structural stability, while the choice of concrete for the first floor was determined by Finnish fire safety regulations and the building’s wood suspended ceiling.

Construction of the site’s residential buildings will be carried out by Helsinki Housing Production Department, using CLT interior elements and laminated veneer lumber (LVL) tile elements. The hotel will be built using CLT space elements and the structure will be reinforced with a cement shaft. Sprinklers are mandatory in all buildings.

“The cellars, first floors and foundations will be built from concrete. Each of the buildings, as well as a separate concrete parking space, will be founded directly onto the bedrock terrain using a wall dam solution. In some parts of the buildings, we will also use a grade beam footing,” says Vilén.

Sweco has employed a team of 10 engineers to prepare preliminary construction plans for the project. According to the original plan timeline, construction of Wood City should have started in 2014.

Source: Rakennuslehti numero 38/ Auri Häkkinen