Dehnungsfugen

Dehnungsfugen are designed gaps between structural elements that permit movement caused by thermal expansion and contraction, moisture-related changes, and structural settlement. They prevent crack formation and damage by isolating movement from adjacent components and maintain weatherproofing.

Applications: In buildings, Dehnungsfugen separate concrete slabs, floor sections, façades, and curtain walls; in civil engineering, they are essential in bridges, tunnels, and road pavements. They also accommodate movement between different materials (concrete – steel).

Construction: A Dehnungsfuge typically comprises a gap, a compressible filler (foam, rubber, mineral wool), backer rods, and a flexible sealant (polyurethane, silicone). A compatible covering or cap may be installed to protect the seal from traffic and weather. The fill absorbs movement; the seal provides watertightness.

Design considerations: Movement capacity (ΔL) depends on temperature range, material properties, and structural tolerances. Joint width, depth, and alignment are planned to ensure safe transfer of loads and water exclusion. Material compatibility, durability, and service life are considered, with attention to adhesion to substrate and to sealant service environment.

Maintenance and standards: Seals deteriorate due to UV, weathering, or traffic; periodic inspection and re-sealing are required. There are national and European standards guiding the design, installation, and testing of Dehnungsfugen and joint sealants.