How to Waterproof Concrete: Methods for Achieving Lasting Protection

How to Waterproof Concrete: Methods for Achieving Lasting Protection

As waterproofing experts, we are often asked about how to waterproof concrete. First though it’s important to define what concrete waterproofing actually is: Concrete waterproofing is where the concrete structure provides sufficient protection against ground water ingress to deliver the required waterproofing performance that is suitable for the intended use of the basement space, without the need for other methods of waterproofing.

Type B (integral), is one of the three types of waterproofing described by British Standard 8102:2022, and the standard describes how “Structures providing Type B protection should be constructed of reinforced concrete …… and designed in accordance with the relevant part of BS EN 1992 (all parts)…”

Technical Drawing showing Integral Waterproofing (Type B)

This comprehensive guide will focus on how to waterproof concrete, whilst also discussing the other types of waterproofing defined within BS 8102:2022. These other types of waterproofing systems can be used alongside concrete waterproofing to provide enhanced performance against groundwater ingress.

Understanding Waterproofing Requirements
The success of any concrete waterproofing project begins with a thorough assessment of requirements and site conditions. Key factors that must be considered include:

Ground Conditions and Water Tables
Understanding the soil composition, groundwater levels, ground gas risk, and potential water pressure caused by higher surrounding ground levels is crucial for selecting appropriate waterproofing systems. We always design waterproofing solutions on the assumption that the structure will be subject to a full head of water pressure at some point in its design life. A thorough site investigation  is therefore valuable in helping to determine most suitable methods of protection.

Structure Use and Environmental Grade
The intended use of the space and required internal environment will determine the necessary level of waterproofing protection. British Standard BS 8102:2022 defines different grades of waterproofing protection based on usage requirements, from basic utility areas to high-grade habitable spaces requiring completely dry environments.

Construction Methods
The construction approach, whether new-build or renovation, will impact the selection of waterproofing systems. Different methods may be more suitable for certain construction techniques or existing structural conditions. Factors such as accessibility, structural limitations, and installation constraints must be carefully evaluated.

Types of Waterproofing Systems
British Standard 8102:2022 outlines three main types of structural waterproofing, each with distinct characteristics and applications:

Type A: Barrier Protection
Type A waterproofing involves applying protective barriers, either internally or externally, to resist water ingress. For example, the Newton HydroBond System provides external protection through pre-applied or post-applied membranes, creating a continuous waterproof layer around the structure. For internal applications, the Newton HydroCoat System offers advanced liquid-applied coating solutions that can be applied directly to finished concrete surfaces.

These barrier systems are particularly effective when:

Complete encapsulation is required
Protection against ground gases is needed
High water tables are present
The structure requires protection from aggressive ground conditions
The success of Type A systems depends heavily on proper surface preparation and application techniques. The membrane must be continuous and properly sealed at all joints and penetrations to ensure complete protection.

Type B: Integral Protection
The Newton HydroTank System represents Type B waterproofing, where the structure itself acts as the primary water barrier. This approach requires careful attention to:

Concrete mix design and placement
Specialised waterbars for construction joints
Waterstops and seals for service penetrations
Capillary blocking treatments
Steel reinforcement design to control cracking
The effectiveness of Type B systems relies heavily on proper concrete placement and joint detailing, making it particularly suitable for new construction projects where quality control can be closely monitored. The concrete must be designed to achieve low permeability while maintaining workability and proper curing conditions.

Type C: Drained Protection
The Newton CDM System exemplifies Type C waterproofing, which takes a different approach by managing water ingress through controlled drainage. This comprehensive system includes:

High-quality cavity drain membranes
Reliable sump and pump systems

Why Is Combination Waterproofing Essential for Concrete Waterproofing?
Combination waterproofing involves using multiple types of protection systems to provide multiple forms of protection and improve the overall effectiveness of the waterproofing solution. BS 8102:2022 specifically recommends this approach when:

Project risks are deemed high
The consequences of failure would be severe
Enhanced protection is required for valuable or sensitive spaces
Environmental conditions are particularly challenging

Our Technical Team frequently recommends combining different systems to provide superior protection. For example, on new-build projects or where the contractor has access to the external face of the below-ground structure, the HydroBond System (Type A) can be effectively combined with the CDM System (Type C) to create a robust waterproofing solution that utilises both water barrier and water management systems.

Key Considerations for Successful Implementation

Surface Preparation
The effectiveness of any waterproofing system, but particularly Type A waterproofing membranes, depends heavily on proper surface preparation. Concrete surfaces must be:

Properly cured before waterproofing application
Repaired of any existing damage or defects
Clean and free from contamination
Mechanically prepared and primed for optimal adhesion
Free from standing water or excessive moisture content

Addressing Critical Areas
Special attention must be paid to potential weak points in the waterproofing system:

Construction joints require careful detailing and appropriate waterstops
Service entries need proper sealing and protection
Floor-wall junctions demand particular attention
Shrinkage cracks must be addressed before waterproofing application
Movement joints require flexible sealing solutions

Environmental Considerations
Various environmental factors can impact waterproofing performance:

Temperature fluctuations affecting material properties and installation
Humidity levels influencing curing and adhesion
Groundwater pressure variations
Seasonal changes in soil conditions
Chemical exposure from surrounding soils and risks from ground gases such as methane, CO2 and radon

Technical Support and Quality Assurance
Professional installation and technical support are crucial for system success. Our team of technical experts will provide:

Appropriate product recommendations and free general advice
Installation guidance
Site supervision, when required
Recommendations for approved, trained and qualified specialist contractors

Furthermore, alongside our network of approved Specialist Basement Contractors, the Waterproofing Design Partnership provides a comprehensive waterproofing design service, backed by professional indemnity insurance and installation guarantees, including:

A comprehensive, project-specific design proposal
Detailed specifications, including technical drawings and product and installation information
Guidance on system costs and ongoing maintenance
Additional services including u-value calculations, condensation risk analyses, gas protection assessments and pump system specifications

Long-Term Performance and Maintenance
Ensuring lasting protection requires ongoing attention to maintenance:

Regular Inspections
Scheduled inspections should check for:

Signs of water ingress or dampness
Integrity of waterproofing membranes
Performance of drainage systems
Condition of seals and joints
Pump system operation

Preventive Maintenance
Implementing a preventive maintenance programme helps avoid costly repairs through:

Regular cleaning of drainage channels
Testing of pump systems
Inspection of control equipment
Documentation of maintenance activities
Prompt addressing of any issues

How Can Newton Waterproofing Help You?
By understanding these various aspects of concrete waterproofing and working with experienced professionals, you can ensure your project achieves the necessary level of protection while meeting all relevant standards and specifications. Remember that successful waterproofing is not just about selecting the right products – it’s about implementing a comprehensive system that addresses all potential water ingress risks while providing long-term, maintainable protection for your structure.

Contact Newton Waterproofing’s technical team today to discuss your project requirements and receive tailored advice on the most appropriate waterproofing system for your needs. Our specialists can help you design an effective solution that provides lasting protection and peace of mind, ensuring your concrete structure remains dry and protected for years to come.