Leppavaara Housing Blocks
Leppavaara Housing Blocks

Toni Yli-Suvanto Architects was commissioned by Espoon Asunnot Oy to find an economically efficient solution for a housing development on a site in Espoo facing particular challenges caused by the busiest highway in Finland – Keha I (Ring I) - running underneath the site. The tunnel structures of the highway would inevitably lead to long span in the foundations, and earlier efforts with traditional approach had proven to be not viable to implement.

The studio solved the challenge firstly by using light yet rigid timber structures in typical floors above the first floor, reducing vastly the vertical loads to the foundations and need for massive concrete structures. The number of the timber floors was increased by optimizing the concept of fire safety, and the volumes of the blocks were developed to match both structural opportunities and spatial needs.

Secondly, an innovative design approach was used for the foundation by designing both structural and architectural solution in seamless integration and channeling the superstructural vertical loads predominately into the spanning concrete structures of the first floor, instead of separate foundation structures. This way, the need for concrete is reduced again, by approximately 50 %.

While the timber superstructure is designed simple and robust for easy tendering and constructing, the room program is designed to match socially sustainable objectives of the client, offering a typology of apartments with three, two or one bedrooms and a set of studios. Balconies are developed to match this typology and to align with the structural concept, and they are designed to block some of the warm southwestern sunlight in the summer.

The developed solution was estimated to have made the project significantly leaner in terms of construction costs. The same time however, the project has become healthier in terms of ecological sustainability. Carbon footprint of the construction is vastly reduced by the minimal need for concrete and by using low carbon and carbon storing timber for all structures above the first floor. Operational carbon footprint is reduced by designing the blocks to the highest national standard in terms of energy-efficiency, and a possibility for green operational energy is offered by allowing for PV panel installations on the roofs.

Location:Leppavaara, Espoo, Finland
Client:Espoon Asunnot Oy, Finland
Project start:2020
Gross Floor Area:9 100 m2
Urban design:Toni Yli-Suvanto Architects
Architecture:Toni Yli-Suvanto Architects
Structure:Sweco Structures
Housing techology:Granlund
Fire safety:KK-palokonsultti