SikaTop 525 Seal | UV-Resistant Flexible Waterproofing Coating

14/07/2026

SikaTop 525 Seal | UV-Resistant Flexible Waterproofing Coating

What is SikaTop®-525 Seal?

SikaTop®-525 Seal is a two-component, cement and acrylic-based flexible waterproofing coating designed to provide long-lasting protection against water penetration. Its UV-resistant formulation makes it particularly suitable for exterior applications where prolonged exposure to sunlight is expected.

The product forms a highly effective waterproof barrier on concrete and cement-based substrates, protecting structures against water, saltwater, and atmospheric conditions. An additional advantage is its ability to be applied to green concrete, helping to reduce project timelines.

Key Features

  • UV-resistant formulation for long-term outdoor performance
  • Flexible coating with crack-bridging capability
  • Excellent adhesion to concrete and cementitious substrates
  • Resistant to saltwater and atmospheric exposure
  • Water vapor permeable, allowing the substrate to breathe
  • Easy application by brush, trowel, or spray equipment
  • Suitable for application on green concrete

Applications

SikaTop®-525 Seal is suitable for a wide range of waterproofing applications in both interior and exterior environments.

Typical applications include:

  • Foundation and retaining wall waterproofing
  • Basement and retaining structures
  • Terraces and balconies
  • Swimming pools and wet areas
  • Water tanks and potable water structures
  • Spa, wellness, and hammam facilities
  • Seawater channels
  • Concrete structures exposed to saline environments

Technical Specifications

  • Product Type: Two-component cement and acrylic-based waterproofing coating
  • Color: Off-white
  • Density: Approximately 1.7 kg/L

Packaging

33 kg set

  • Component A: 25 kg powder
  • Component B: 8 kg liquid

Coverage

Approximately 1.7 kg/m²/mm

(A minimum of two coats is recommended.)

Application Temperature

+8°C to +30°C

Strength Development

  • After 2 days: Mechanical strength
  • After 7 days: Waterproof performance
  • After 14 days: Full strength

Shelf Life

12 months when stored under appropriate conditions in unopened original packaging.

Advantages

Excellent Adhesion

Provides outstanding bonding performance on concrete and other mineral substrates.

UV Resistance

Maintains long-term performance in outdoor applications exposed to direct sunlight.

Breathable System

Its water vapor permeability helps prevent moisture accumulation within the substrate.

Weather Resistance

Resistant to freeze-thaw cycles and harsh atmospheric conditions.

Faster Project Completion

Can be applied directly onto green concrete, reducing waiting times during construction.

Application Procedure

1. Surface Preparation

The substrate must be clean, sound, and free from dust, oil, grease, and loose particles. Cracks and voids should be repaired using appropriate Sika repair mortars before application.

2. Mixing

Pour Component B into a clean mixing container. Gradually add Component A while mixing with a low-speed mechanical mixer until a smooth, homogeneous mixture is obtained.

3. Application

Apply at least two coats using a brush, trowel, or spray equipment. Allow approximately 3 to 12 hours between coats, depending on ambient temperature and weather conditions.

4. Curing

Protect the freshly applied coating from direct sunlight, rain, and frost during the first 24 hours. Maintain suitable curing conditions for approximately 3 to 5 days.

5. Protective Finish

Where pedestrian traffic is expected, it is recommended to install a screed or ceramic tile finish over the waterproofing layer.

Frequently Asked Questions (FAQ)

Where can SikaTop®-525 Seal be used?

It is suitable for foundations, retaining walls, terraces, swimming pools, water tanks, spa facilities, hammams, and concrete structures exposed to saltwater.

Is it UV resistant?

Yes. Its UV-resistant formulation makes it ideal for outdoor waterproofing applications exposed to direct sunlight.

How many coats should be applied?

A minimum of two coats is recommended to achieve the required waterproofing performance.

Can it be applied on green concrete?

Yes. SikaTop®-525 Seal can be applied directly onto freshly placed (green) concrete, helping to accelerate construction schedules.

What packaging is available?

The product is supplied as a 33 kg set, consisting of 25 kg powder (Component A) and 8 kg liquid (Component B).

SikaTop®-525 Seal is a high-performance flexible waterproofing coating that combines excellent UV resistance, crack-bridging capability, and superior adhesion to provide durable protection for concrete structures exposed to water, weather, and aggressive environmental conditions.