The visitor journey begins at sea level, where guests walk up a path through the forest toward the building. Gradually emerging from the hillside, the structure reveals itself as part of the forested landscape. The building mass is articulated as a rhythmic series of volumes that reduce its scale while framing views toward the fjord and surrounding mountains.

The geothermal water used in the lagoon originates from a source discovered by accident during the construction of the Vaðlaheiði tunnel in 2014. What began as an unforeseen condition revealed a valuable natural resource that ultimately shaped the project. In 2022, the water was redirected to the Forest Lagoon, transforming this technical challenge into a sustainable asset—environmentally, socially and economically.

This integration of natural systems extends into the sensory experience of the baths. Running water, including a redirected natural creek, a new waterfall near the outdoor seating area, and the cascading water of the baths, is strategically used to minimize noise from traffic.

The building is constructed using a combination of cross-laminated timber (CLT) and prefabricated concrete. The front portion of the building is formed from timber construction with wood interiors and an open lightwell that brings a tree into the entrance space. Toward the mountain, precast concrete volumes follow the rock of the hillside and frame the transition through changing rooms toward the lagoon.

Materials are expressed in their raw state. CLT structure and precast concrete surfaces remain visible throughout the interior. Exterior wood cladding is produced from factory offcuts sawn into diagonal strips, creating a textured surface that references the rhythm and silhouette of the surrounding forest.

The preserved woodland provides natural shelter from wind and frames views toward the fjord, allowing the bathing experience to unfold in close dialogue with the forest landscape.