Precast construction with advanced watertight seal technology

Denso’s Viscotaq Precast Structure Sealing System delivers a watertight, flexible seal designed to stop liquid, gas, and contaminant infiltration in precast concrete and manhole assemblies.

The Viscotaq Precast Sealing System is engineered to combat water intrusion, by sealing seams and joint areas in municipal infrastructure and precast concrete. The system helps preserve structural integrity, extend service life, and significantly reduce long-term maintenance and repair costs.

The system comprises Denso’s Viscotaq line, a visco-elastic, non-shrinking coating, which includes ViscoMastic, ViscoSealant, and ViscoWrap (or optionally Viscotaq EZ Wrap). After cleaning the concrete area, installation of the Viscotaq products can begin. For smooth precast sections, ViscoMastic, a semi-solid polyolefin mastic coating, is applied as a thick bead between concrete sections compressed by the weight of the incoming sections to form a continuous watertight seal. For existing seams and joints, apply ViscoSealant into the void, smooth with a putty knife, and then apply ViscoWrap over the joint.

Viscotaq materials are inherently self-healing, designed with viscosity to provide permanent wetting characteristics and elasticity to offer the strength and feel of a semi-solid, even under stress or settlement. The Viscotaq system requires minimal surface preparation (typically hand-tool cleaned to SP2 levels) and adhere instantly without primer. Viscotaq materials are inert, UV-resistant, non-toxic, solvent-free, carcinogen-free, and resistant to harsh soils, freeze–thaw cycling, and a wide range of temperatures.

Widely used for sealing box culverts, manholes, concrete chambers, and vault structures, the Viscotaq system adapts to any size or configuration without shrinking over time. The flexible and durable bond creates a permanent seal that prevents infiltration of water, soil and gases that enhance durability and reduce environmental contamination risks. Moreover, the system enables efficient field application, ideal for on-site installation and repairs, even in tight or hard-to-access joints, ensuring long-term resilience with minimal disruption.