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How to Choose the Right Waterproofing Membrane

Written by Layla May | Aug 5, 2025 11:58:25 PM

Choosing the right waterproofing membrane is crucial to ensuring your commercial or industrial project stands strong against water intrusion for decades. Whether protecting parking decks, water/wastewater tanks, tunnels, or plazas, understanding membrane types, applications, and specification criteria enables successful waterproofing.
This guide compares liquid-applied and sheet membranes, explains CIM’s product lineup for various substrates and environments, and shares installation and QA best practices to avoid costly errors.

Liquid-Applied vs. Sheet Membranes: What You Need to Know

Feature Liquid-Applied Membrane Sheet Membrane
Seamless Coverage Monolithic layer, no laps 
or seams
Overlaps and heat welds 
create seams
Complex Shapes Easily conforms to 
penetrations, corners, 
curves
Difficult for irregular 
geometries
Cure Time Fast curing (minutes to 
hours)
Longer cure unless heat welding
Repair & Maintenance Simple spot repair 
possible
Repairs often & re-welding
Climate Adaptability  Cold-applied options 
available 
Temperature dependent 
adhesion
Best Use Cases Irregular tanks, plaza 
decks, tunnels
Large flat roofs or slabs 
with minimal penetrations

 

Why CIM Specializes in Liquid-Applied Membranes

For over 50 years, CIM has been a pioneer in engineered industrial coatings, developing high-performance waterproofing systems that meet stringent VOC regulations and deliver proven results in the most demanding environments.

At the core of CIM’s success is our advanced liquid-applied membrane technology, which forms seamless, fully bonded, and highly elastic barriers. These membranes excel in complex, high-risk applications, such as industrial tanks, tunnels, plaza decks, and confined spaces, where chemical resistance, flexibility, and long-term durability are non-negotiable.

What sets CIM apart is more than just durability. Our membranes offer exceptional crack-bridging capability, a critical feature for concrete structures where movement and settling are expected. In addition, CIM systems feature extremely low permeability, delivering superior protection against water intrusion compared to typical liquid-applied options.

Our product line is carefully engineered for fast cure times, environmental safety (including zero-VOC solutions), and unmatched performance, a reflection of CIM’s legacy of innovation and commitment to quality.

Matching CIM Membranes to Your Project Needs

Application CIM Product Benefits & Certifications
Chemical and wastewater tanks CIM 1000 Strong, chemical-resistant urethane coating
Potable Water Tanks & Reservoirs CIM 1061 ANSI/NSF Standard 61 certified; specifically formulated and tested for 
safe contact with potable water
Potable Water Application & Vertical walls and ceilings CIM 1000 TG Trowel-grade, sag-resistant for overhead and vertical applications, potable water
Confined or indoor spaces CIM Eco 1000 Zero-VOC, low-odor formulation retaining strength of CIM 1000, 
ideal for occupied or confined areas
Exposed decks and roofs CIM 800 or CIM 1000 UV/weather-resistant urethane for exposed surfaces; high durability 
outdoors. Warranty limits for 800.
Fast curing, quick return time jobs CIM 500 High-strength, low permeability, especially for horizontal 
surfaces with tight schedules

Priming:
Use EMT Primer on steel, concrete, or other challenging substrates to ensure proper adhesion and a moisture-tolerant base.

Want detailed substrate-specific guidance for applying waterproofing membranes?
Download CIM’s complete Waterproofing Application Guide for Commercial and Industrial Projects

FAQ'S

Q: How long do CIM liquid-applied membranes last?

A: When correctly installed and maintained, CIM membranes offer 20+ years of reliable waterproofing and chemical 
resistance.

 

Q: Which CIM coatings are certified safe for potable water tanks?

A: CIM 1061 and CIM 1000 TG are both potable water approved. Additionally, our EMT Primer and CIM VOC Compliant Bonding Agent is also approved. 

 

Q: What preparation is critical before membrane application?

A: The substrate must be clean, dry, sound, and properly primed with EMT Primer, especially on metals or 
concrete surfaces, to ensure strong adhesion and coating performance.

Success Story Highlight

At a major Belgian brewery, CIM 1000 was applied in a single coat on a steel leachate tank, enabling a return to service in 48 hours and providing seamless, long-term leak protection.

Learn More: https://library.chasecorp.com/wp-content/uploads/2020/05/Case-Study-CIM-Belgium-Brewery-%E2%80%93-Waste-Process-Tank.1-Read-Only.pdf

Installation Best Practices

  •  Abrasive blast or pressure wash to remove old coatings, dirt, and contaminants.
  • Achieve ICRI CSP 4-6 profile on Concrete Applications. 
  • Prime with EMT Primer for optimal adhesion.
  • Apply recommended wet mil thickness. Minimum recommended thickness is 60 mils with applications as high as 120 mils. 
  • Verify installation with ASTM D903 peel adhesion and ASTM D5385 flood tests.