Lahti City Hall, a protected Jugendstil building, underwent an extensive renovation (completed 2023) that included sustainable upgrades to its surrounding grounds. As part of this renewal, Organic-Lock Stabilized Aggregate was introduced in the courtyards and walkways to replace or augment old asphalt. The OLSA surfaces improved stormwater management around the historic structure and preserved the heritage aesthetics with a natural beige-gray tone.