During the reconstruction of Hiiu School, Traveter Grupp carried out comprehensive waterproofing of the foundations of both the old and the new part of the building. The aim was to create a durable below-ground moisture and water barrier that protects the structures from groundwater and rainwater and ensures the long-term serviceability of the building.

On the old part of the building, the work began with thorough cleaning of the foundation wall and levelling of irregularities with shotcrete. A thick-layer, sprayable bitumen-polymer waterproofing and thermal insulation were then applied, which together provide the structure with effective moisture protection and thermal performance.

On the new part of the building, waterproofing was installed under the raft foundation and in the lift shaft, and all penetrations were sealed. In addition, a basement waterproofing system was built, including forming coves, priming, installing a self-adhesive membrane, sealing penetrations, thermal insulation and a drainage mat. Particular attention was paid to the watertightness of all joints and penetrations to ensure the long-term reliability of the system 6 m below ground.