Merks Sealmax CB 504 | Semi-Elastic Cement & Acrylic Based Waterproofing Membrane

28/07/2026

Merks Sealmax CB 504 | Semi-Elastic Cement & Acrylic Based Waterproofing Membrane

Merks Sealmax CB 504: Semi-Elastic Waterproofing Solution for Wet Areas and Structural Surfaces

Merks Sealmax CB 504 is a cement and acrylic-based semi-elastic waterproofing membrane designed to provide reliable protection against water penetration in residential, commercial, and industrial structures. Applicable by brush, roller, or thin trowel, it offers excellent adhesion and long-lasting waterproofing performance on both horizontal and vertical surfaces.

Thanks to its pre-measured liquid and powder components, the product ensures easy mixing and consistent application without requiring additional water.

Key Features

  • Cement and acrylic-based formulation
  • Semi-elastic waterproofing performance
  • Excellent adhesion to mineral substrates
  • Suitable for horizontal and vertical applications
  • Can be applied by brush, roller, or trowel
  • Paintable surface after curing
  • Suitable for contact with potable water
  • Ready-mix component ratio for easy preparation
  • Ideal beneath ceramic tile installations in wet areas

Areas of Application

Merks Sealmax CB 504 is suitable for a wide range of waterproofing applications, including:

  • Bathrooms, toilets, showers, and other wet areas
  • Basement walls
  • Retaining walls
  • Repair and renovation projects
  • Bonding bridge applications
  • Interior and exterior waterproofing surfaces

Advantages

Easy Application

The product can be applied using a brush, roller, or thin trowel, making installation simple and efficient.

Strong Adhesion

Provides excellent bonding performance on concrete, cement-based renders, and masonry surfaces.

Waterproof Protection

Creates a durable barrier against water penetration while maintaining vapor permeability.

Potable Water Compatibility

Suitable for applications involving contact with drinking water.

Ceramic Tile Compatibility

Allows direct ceramic tile installation over cured waterproofing layers in wet areas.

Surface Preparation

Before application, the substrate must be:

  • Clean, sound, and free of dust
  • Free from oil, grease, rust, and loose particles
  • Repaired where necessary using Merks Repair Plus repair mortars

Cracks, cavities, and damaged areas should be repaired before waterproofing. Surfaces should be lightly dampened prior to application and protected from direct sunlight. Corners, joints, and pipe penetrations should be reinforced using Bandix Corner Tape.

Mixing Instructions

  1. Shake Component B thoroughly and pour it into a clean mixing container.
  2. Slowly add Component A while mixing with a low-speed drill mixer.
  3. Continue mixing until a homogeneous, lump-free consistency is achieved.
  4. Allow the mixture to rest for 3–5 minutes.
  5. Mix again for approximately 30 seconds before application.

The prepared material should be used within 30–40 minutes at 20°C.

Application Procedure

First Coat

Apply the first coat evenly in a single direction using a brush or roller.

Second Coat

Once the first coat has cured sufficiently, apply the second coat perpendicular to the first coat.

Additional Coats

For areas exposed to higher water pressure, additional coats may be applied according to project requirements.

Consumption

  • Approx. 1.5 kg/m² per coat
  • Recommended two-coat application: 3–3.5 kg/m²
  • High water pressure applications: 4–5 kg/m² (3–4 coats)

Curing Times

PropertyTime
Mechanical Strength3 Days
Waterproof Performance7 Days
Final Strength14 Days

Technical Specifications

PropertyValue
Component ACement, mineral fillers, polymer additives
Component BCopolymer acrylic dispersion
Component CNatural aggregate
Mixing Ratio20 kg powder / 6 L liquid
DensityApprox. 1.50 kg/L
Pot LifeApprox. 30 minutes
Adhesion Strength≥ 1 N/mm² (28 days)
Water Vapor PermeabilityClass I
Application Temperature+5°C to +35°C
Service Temperature-10°C to +60°C
Mechanical Resistance3 days
Waterproofing Performance7 days
Tile/Covering ApplicationAfter 3 days

Packaging and Storage

  • 26 kg set
    • 20 kg reinforced kraft bag (powder component)
    • 6 kg plastic container (liquid component)

Store unopened packages in dry, frost-free conditions. Shelf life is 12 months from the production date.

Important Notes

  • Apply only on the positive water pressure side.
  • Ambient and substrate temperatures must be between +5°C and +35°C.
  • The second coat should be applied at a 90-degree angle to the first coat.
  • Surfaces exposed to traffic or impact should be protected with an additional protective layer.
  • Protect the liquid component from freezing.
  • Clean tools immediately after use with water.

Frequently Asked Questions (FAQ)

1. Where can Merks Sealmax CB 504 be used?

It is suitable for wet areas, basements, retaining walls, repair applications, and general waterproofing projects.

2. Can ceramic tiles be installed over the product?

Yes. After the waterproofing layer has cured, ceramic tiles can be installed directly over the surface.

3. How many coats should be applied?

A minimum of two coats is recommended. Additional coats may be required in areas exposed to higher water pressure.

4. Is it suitable for contact with drinking water?

Yes. Merks Sealmax CB 504 is suitable for applications involving contact with potable water.

Why Choose Merks Sealmax CB 504?

Merks Sealmax CB 504 combines the strength of cement-based waterproofing with the flexibility of acrylic technology. Its easy application, strong adhesion, potable water compatibility, and durable waterproofing performance make it an ideal solution for wet areas, basements, retaining walls, and various structural waterproofing projects.