How to Terminate Waterproof Coating Systems

Posted by Maribeth Taylor on Feb 9, 2022 2:27:17 PM
Maribeth Taylor
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Terminate Waterproof Coating System

Identifying termination points and properly terminating waterproof coatings are two critical aspects of a waterproofing system’s long-term success. Whether you are applying the coating system to a roof, floor, tank, or fountain; in hot or cold climates; or to concrete, wood, steel, or any other construction materials, correctly terminating the waterproofing system is essential. 

Termination points are areas where the waterproofing membrane stops or is no longer applied. Seasoned waterproofing applicators will identify, plan, and physically mark out where they will terminate the membrane to avoid surprises during application and ensure the product performs as designed.  


Where to Terminate Waterproofing

Most waterproofing membrane systems recommend terminating a minimum of 8 - 12 inches above, away from, or beyond critical areas. Critical areas are physical locations on the job that pose the most significant risk to waterproofing failure. Waterproofing membranes that end at or below critical points are vulnerable to moisture infiltration because water can enter behind the membrane and continue to migrate, causing further damage. This practice of termination is common for most waterproofing systems, including self-adhered, single-ply, and liquid-applied systems.  

Examples of critical areas:  

  • service areas 
  • inside and outside corners 
  • electrical or plumbing penetrations  
  • seams, cracks, or joints in the construction 
  • screws, nails, bolt penetrations, or similar fastened areas
  • reinforced areas 
  • areas with patches or repairs 
  • tie-ins with existing coatings 
  • areas prone to leaks or damage 
  • areas prone to ponding water  

Water feature

Related Article: Comparing Waterproofing Systems: Cold Fluid Applied vs Self-Adhered Sheet Membrane


Methods for Terminating Waterproofing

Manufacturers of waterproof coatings have written instructions for the best means and methods to terminate their coating systems. It's essential to consult with the manufacturer for their specific requirements. Self-adhered, single-ply, and liquid-applied systems are examples of coating systems that terminate in one or more of the following manners: 

  • self-terminating (typically 8-12" from critical areas as described above) 
  • keyways (narrow channels cut to provide strong anchor points for the coating and prevent delamination or peeling at the termination point) 
  • set in a bead of sealant 

Note: When working with liquid-applied waterproof coatings, it is essential to maintain uniform thickness at the termination point and avoid feathering the membrane. 

Related Article: Common Waterproofing Mistakes


In conclusion, it's always best to plan your application and terminations per the manufacturer's written instructions and recommendations. 

CIM's two-part urethane fluid-applied liners and coatings have kept liquids where they belong for over 50 years. Our technical representatives can assist you with product information to meet your coating needs; pleasecontact us.  

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Topics: Coating Application Preparation, Liquid Applied Waterproofing, waterproofing, Fluid-applied Waterproof Membranes

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