Härmälänsydän is a four-story wooden CLT apartment building. Together with seven other apartment buildings it forms a housing block around a residential park. There are 23 apartments in total, ranging from 29,5 m² studios to 64 m² in three-room apartments. Härmälänsydän is the second building of its kind that implements a new kind of construction technology - Sydänpuu, developed by Casagrande Laboratory for Lakea Oy. This building concept joins precast concrete spatial elements and wooden CLT spatial elements into one structure.