Which Sealtek Waterproofing Product Do I Need? A Complete Guide to the Waterproofing Range

Which Sealtek Waterproofing Product Do I Need? A Complete Guide to the Waterproofing Range

Choosing the right waterproofing product is not always as simple as finding a coating that says “waterproof” on the label.

A concrete slab behaves differently from a metal roof. Roof joints and overlaps may need additional reinforcement. Some surfaces experience significant expansion and contraction, while others require a reinforced membrane system to provide the strength needed for the application.

That is why Sealtek offers several different waterproofing solutions rather than a single product for every job.

The Sealtek waterproofing range consists of HydroBlock, HydroFlex, HydroFlex Fibre, FlexTek and ArmTek. Each has been developed for different waterproofing requirements, surfaces and levels of reinforcement.

This guide will help you understand the difference between them and provide a practical starting point for choosing the right Sealtek system for your project.

Start With What You Are Waterproofing

Before choosing a product, consider the surface and the type of waterproofing problem you are trying to solve.

Are you working on:

  • A concrete slab?
  • A flat roof?
  • An IBR or corrugated metal roof?
  • A tiled roof?
  • Flashings or parapets?
  • Roof joints or overlaps?
  • Foundations?
  • Retaining walls?
  • An area where additional reinforcement is required?

You should also consider the condition of the substrate.

Existing waterproofing, contamination, moisture, surface deterioration and movement can all affect how a waterproofing system needs to be prepared and applied.

The right product is therefore only one part of the solution. Correct preparation, specification and application are equally important to waterproofing performance.

A Quick Guide to the Sealtek Waterproofing Range

As a simple starting point:

HydroBlock
A versatile pure acrylic waterproof coating for applications including slabs, roofs and foundations.

HydroFlex
A highly flexible pure acrylic waterproof coating with up to 450% stable elongation, ideally suited to IBR, corrugated metal, tiled roofs, flashings and parapets.

HydroFlex Fibre
A flexible pure acrylic waterproof coating containing hair-like polypropylene fibres for added reinforcement and strength. Ideally suited to roof tiles, IBR and parapets.

FlexTek
A reinforced waterproofing system combining a flexible acrylic coating with a Spunfab woven membrane. Ideal for applications such as IBR joints, tiled roofs and overlaps.

ArmTek
A reinforced pure acrylic waterproofing system using an acrylate-coated fibreglass membrane. Ideal for flat concrete slabs, retaining walls and similar demanding applications.

These are useful starting points, but the condition and requirements of the actual project should always be considered before a system is selected.

HydroBlock: Versatile Seamless Waterproofing

When should you consider HydroBlock?

HydroBlock is an eco-friendly, pure acrylic waterproof coating developed for a wide range of waterproofing applications.

It is adhesion-promoted, UV-stable, flexible and durable, making it a versatile option for waterproofing areas such as:

  • Concrete slabs
  • Roofs
  • Foundations
  • Walls

Because HydroBlock is liquid-applied, it creates a seamless waterproof coating over the prepared surface.

This makes it particularly useful where you want continuous waterproof protection without the joints associated with some traditional membrane systems.

HydroBlock waterproofing application

When HydroBlock is used for waterproofing purposes, the Sealtek specification requires a four-coat application of approximately 2,000 microns.

Depending on the condition of the substrate, a 20-litre container provides approximately 10–25 m² of practical coverage for a waterproofing application.

When only two coats are applied, the resulting coating is approximately 800–1,000 microns and is considered water-resistant rather than waterproof.

That distinction is important.

If the purpose of the project is waterproofing, the complete waterproofing specification must be followed.

HydroFlex: When Maximum Flexibility Matters

When should you consider HydroFlex?

HydroFlex is also a pure acrylic waterproof coating, but its defining characteristic is its exceptional flexibility.

The product provides up to 450% stable elongation, allowing the coating to accommodate substantial movement while maintaining its protective barrier.

This makes HydroFlex particularly well suited to:

  • IBR roofs
  • Corrugated metal roofs
  • Tiled roofs
  • Flashings
  • Parapets

HydroFlex adheres to concrete, masonry, wood and metal surfaces when correctly prepared.

Its flexibility is particularly valuable on roofing materials that expand and contract as temperatures change.

Metal roofing is a good example. During hot conditions, metal expands. When the temperature drops, it contracts again. Waterproofing used on these surfaces therefore needs to cope with repeated movement.

HydroFlex waterproofing application

For waterproofing applications, the Sealtek specification requires a four-coat HydroFlex system of approximately 2,000 microns.

Practical coverage is approximately 10–25 m² per 20 litres, depending on substrate conditions.

A two-coat application produces a coating of approximately 800–1,000 microns and provides water resistance, but is not considered a complete waterproofing application.

If movement and flexibility are major considerations on the project, HydroFlex is an important product to consider.

HydroFlex Fibre: Flexibility With Built-In Fibre Reinforcement

When should you consider HydroFlex Fibre?

HydroFlex Fibre combines a highly flexible pure acrylic waterproof coating with hair-like polypropylene fibres incorporated into the product.

These fibres reinforce and strengthen the coating while retaining its flexibility.

HydroFlex Fibre is ideally suited to applications including:

  • Roof tiles
  • IBR roofs
  • Parapets

It adheres to concrete and metal surfaces when correctly prepared.

One of the specific advantages identified in the Sealtek specification is its ability to fill small gaps, making it useful where additional reinforcement within the coating itself is beneficial.

HydroFlex Fibre waterproofing application

Like HydroBlock and HydroFlex, HydroFlex Fibre requires a four-coat application of approximately 2,000 microns for waterproofing purposes.

Depending on substrate conditions, practical waterproofing coverage is approximately 10–25 m² per 20 litres.

A two-coat application of approximately 800–1,000 microns provides water resistance but is not considered waterproofing.

HydroFlex Fibre vs HydroFlex

The main distinction is the added polypropylene fibre reinforcement.

HydroFlex provides exceptional flexibility.

HydroFlex Fibre provides a flexible waterproofing coating while adding fibres that reinforce and strengthen the coating.

However, this should not be confused with a waterproofing system incorporating a separate reinforcing membrane.

Where woven or fibreglass membrane reinforcement is required, FlexTek or ArmTek may be more appropriate.

FlexTek: Reinforced Waterproofing for Joints, Overlaps and Roof Areas

When should you consider FlexTek?

Certain waterproofing applications benefit from more than a liquid coating alone.

FlexTek is a pure acrylic waterproofing system that combines an extremely flexible FlexTek coating with a Spunfab woven membrane.

The reinforcing membrane increases the strength and lifespan of the finished waterproofing system.

According to the Sealtek specification, FlexTek is ideal for applications including:

  • IBR joints
  • Tiled roofs
  • Roof overlaps

These are areas where movement, joints and transitions can create vulnerable points in the waterproofing system.

Instead of relying only on the coating, the Spunfab membrane is incorporated into the system and encapsulated by the waterproofing coating.

FlexTek waterproofing application

A FlexTek system consists of:

  • FlexTek waterproof coating
  • Spunfab woven membrane

A 20-litre FlexTek system with 12 m² of membrane provides approximately 12 m² of practical coverage, based on a three- to four-coat application.

The first coating layer is applied sufficiently thick to facilitate saturation of the membrane. Once touch dry, subsequent coats encapsulate and protect the reinforced system.

This creates a seamless waterproofing system with additional physical reinforcement where it is required.

ArmTek: Reinforced Waterproofing for Flat Concrete Slabs and Structures

When should you consider ArmTek?

ArmTek represents a more substantial reinforced waterproofing approach.

It is a pure acrylic system developed as a replacement for traditional torch-on waterproofing systems.

ArmTek combines:

  • ArmTek waterproof coating
  • An acrylate-coated fibreglass membrane
  • Damp-End as the specified preparation system

The fibreglass membrane increases the strength, flexibility and durability of the completed waterproofing system.

ArmTek is particularly suited to:

  • Flat concrete slabs
  • Retaining walls
  • Similar structural waterproofing applications requiring reinforced protection

ArmTek waterproofing application

The ArmTek system uses an acrylate-coated fibreglass membrane that is saturated and encapsulated by the waterproof coating.

A 20-litre system with approximately 14 m² of fibreglass membrane provides around 14 m² of practical coverage, based on a guideline three- to four-coat application.

The membrane reinforcement differentiates ArmTek from Sealtek's coating-only waterproofing products.

For flat slabs and applications where substantial continuous reinforcement is required, ArmTek provides a seamless reinforced alternative to traditional torch-on waterproofing.

What Is the Difference Between HydroFlex Fibre, FlexTek and ArmTek?

All three involve reinforcement, but they achieve it in different ways.

HydroFlex Fibre

The reinforcing polypropylene fibres are already incorporated into the liquid coating.

This strengthens the coating and assists with filling small gaps.

FlexTek

FlexTek uses a separate Spunfab woven membrane that is saturated and encapsulated by the flexible acrylic waterproofing coating.

It is particularly suited to areas such as IBR joints, tiled roofs and overlaps.

ArmTek

ArmTek uses an acrylate-coated fibreglass membrane to create a stronger reinforced waterproofing system, particularly for flat concrete slabs, retaining walls and similar applications.

Understanding this difference helps explain why the products should not simply be viewed as interchangeable waterproofing coatings.

The level and type of reinforcement should suit the application.

Waterproofing vs Water Resistance: Why the Number of Coats Matters

One of the most important distinctions within the Sealtek range is the difference between painting a surface with a water-resistant coating and installing a waterproofing system.

For HydroBlock, HydroFlex and HydroFlex Fibre, the specification is clear:

Four coats at approximately 2,000 microns are required for waterproofing purposes.

Two coats result in a coating of approximately 800–1,000 microns that provides water resistance, but the substrate should not be considered fully waterproofed.

FlexTek and ArmTek operate differently because they incorporate separate reinforcing membranes and follow their respective system specifications.

This is why waterproofing should never be approached simply as:

“How many coats of paint should I put on?”

The objective is to create the required complete system at the correct coverage and film build.

Surface Preparation Is Part of the Waterproofing System

Choosing the right product will not compensate for incorrect surface preparation.

Sealtek's specifications require existing coatings and contaminants that may affect adhesion to be removed before application.

This can include:

  • Dust
  • Debris
  • Salt
  • Algae
  • Fungi
  • Chemicals
  • Existing waterproofing where the specification requires its removal

For HydroBlock, HydroFlex and HydroFlex Fibre, the substrate should be completely dry before application, with less than 10% moisture.

The correct primer also depends on the substrate and the waterproofing system being used.

For HydroBlock, HydroFlex and HydroFlex Fibre

On cementitious substrates, Repellam or AquaTint is specified as the primer.

No primer is required on metal surfaces under these systems.

For FlexTek

On cementitious substrates, Repellam or Damp-End is specified.

These primers should not be applied to metal substrates when using the FlexTek system.

For ArmTek

Damp-End forms part of the specified substrate preparation before the ArmTek system is applied.

This reinforces an important principle:

Waterproofing performance depends on the complete system — not only the final coating.

So, Which Sealtek Waterproofing Product Should You Choose?

If you are trying to narrow down the options, use the following as a starting point.

Consider HydroBlock if:

You need a versatile pure acrylic waterproof coating for applications such as slabs, roofs, foundations or walls.

Consider HydroFlex if:

You are working with IBR, corrugated metal, tiled roofs, flashings or parapets where high flexibility and movement accommodation are important.

Consider HydroFlex Fibre if:

You need flexible waterproofing with added polypropylene fibre reinforcement, particularly on roof tiles, IBR or parapets.

Consider FlexTek if:

You need a membrane-reinforced waterproofing system for applications such as IBR joints, tiled roofs or overlaps.

Consider ArmTek if:

You are waterproofing flat concrete slabs, retaining walls or similar areas where a reinforced fibreglass membrane system is appropriate.

The right choice, however, should still take the actual condition of the surface and the waterproofing problem into account.

When Should You Get Professional Waterproofing Advice?

Water ingress does not always originate from the most obvious location.

The visible leak may be caused by problems elsewhere, including:

  • Failed joints
  • Cracks
  • Flashing defects
  • Roof penetrations
  • Surface deterioration
  • Existing failed waterproofing
  • Structural or thermal movement
  • Incorrect drainage

For larger areas, recurring leaks, reinforced waterproofing applications or situations where the cause of the problem is uncertain, professional assessment can help ensure that the correct system is specified before work begins.

Sealtek Accredited Applicators are trained to work with Sealtek systems and application requirements.

Sealtek products carry a 5-year guarantee when correctly installed by Sealtek Accredited Applicators and maintained according to specification.

Choose a Waterproofing System, Not Just a Product

Good waterproofing starts by matching the system to the surface and the problem.

HydroBlock provides a versatile pure acrylic waterproofing option for a broad range of applications.

HydroFlex adds exceptional flexibility for roofs and areas exposed to movement.

HydroFlex Fibre combines flexibility with polypropylene fibre reinforcement.

FlexTek introduces a Spunfab woven membrane for reinforced waterproofing around areas such as roof joints, tiled roofs and overlaps.

ArmTek uses an acrylate-coated fibreglass membrane for reinforced waterproofing of areas such as flat concrete slabs and retaining walls.

But whichever system is selected, the same fundamentals remain important:

Correct product. Correct preparation. Correct application. Complete system.

Not Sure Which Sealtek Product Is Right for Your Project?

You do not need to guess.

Tell the Sealtek team what you need to waterproof, what the surface is made from and what problem you are experiencing.

We can help you identify the appropriate waterproofing system, provide technical guidance and connect you with a Sealtek Accredited Applicator where professional application is required.

Explore the Sealtek waterproofing range online or contact Sealtek for assistance with your project.

Sealtek — waterproofing solutions built for South African conditions.

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