Water is one of the most persistent threats to any building structure, capable of causing extensive damage if left unchecked. From heavy rainfall, high water tables, or poor drainage, moisture can infiltrate walls and foundations, leading to mould growth, structural weakening, and costly repairs.
This is where external waterproofing comes into play. As a critical measure in construction and renovation, external waterproofing provides a strong, protective barrier that prevents water from penetrating the building’s exterior.
This blog will explore external waterproofing, its essentials, and how different methods can safeguard your property from water-related damage.
Let’s get straight to the point.
External waterproofing is crucial for protecting buildings from water infiltration, which can lead to structural damage, mould growth, and costly repairs. It involves applying waterproof membranes and drainage systems to the exterior of a building to prevent moisture from penetrating walls and foundations.
Common methods include bituminous membranes, liquid waterproofing, cementitious coatings, and waterproof coatings. This process helps maintain a building’s structural integrity, improves indoor air quality, and extends the building’s lifespan.
Importance Of External Waterproofing
One of the most important considerations in construction and renovation is ensuring that water does not penetrate the structure. Moisture can cause a range of issues, including mould growth, structural damage, and the deterioration of building materials.
By applying external waterproofing measures, property owners can safeguard their buildings against these risks and extend the lifespan of their investments.
Protection From Water Infiltration
Water infiltration poses a serious risk to a building’s structural integrity, especially when unresolved. Water penetrating the foundation or walls can weaken critical structural components, leading to cracks, erosion, and potential collapse over time.
This is particularly concerning in regions with high rainfall or water tables, where the risk of infiltration is significantly elevated. External waterproofing serves as the primary barrier to prevent water from entering the building, ensuring that it remains structurally sound and reducing the likelihood of costly repairs due to water damage.
Preventing Damp And Mould
Dampness inside a building creates the perfect environment for mould and mildew to thrive, leading to various problems. Beyond the musty odours that mould produces, it can severely impact indoor air quality and the health of the occupants.
Prolonged exposure to mould spores can trigger respiratory issues, allergies, and even serious health conditions in vulnerable individuals. By installing external waterproofing measures, property owners can prevent moisture from penetrating the building, thus avoiding the damp conditions that encourage mould growth, ensuring a safer and healthier indoor environment.
Increasing Building Longevity
External waterproofing significantly contributes to a building’s long-term durability.
Preventing moisture from seeping into the structure ensures that materials such as concrete, brick, and wood remain intact and functional for an extended period. Moisture can cause materials to degrade over time, leading to premature wear, cracking, and structural failure.
Waterproofing minimises the need for frequent repairs and preserves the building’s visual appeal by protecting surfaces from staining, weathering, and discolouration. This proactive measure extends the building’s lifespan and reduces overall maintenance costs.
Common Methods Of External Waterproofing
Several techniques can be employed to waterproof a building’s exterior. The choice of method depends on the structure, the materials used, and the level of protection required.
Below are some of the most common external waterproofing methods.
Bituminous Membranes
Bituminous membranes are a popular choice for waterproofing because they are highly effective at creating a protective barrier against water.
These sheets are made from bitumen, a sticky, black substance derived from petroleum. The membranes are applied to the external surfaces of buildings, particularly in areas prone to water exposure, such as foundations and basements.
Advantages:
- Durable and long-lasting.
- Excellent resistance to water infiltration.
- It can be applied in multiple layers for added protection.
Liquid Waterproofing Membranes
Liquid waterproofing membranes are another common solution for external waterproofing.
These membranes are applied as a liquid and solidified to form a flexible, watertight barrier.
They are ideal for covering uneven surfaces or areas with complex geometries, as the liquid easily conforms to the surface’s shape.
Advantages:
- Easy to apply to irregular surfaces.
- Provides a seamless barrier with no joints or seams.
- Highly adaptable for various external surfaces, including walls and roofs.
Cementitious Waterproofing
Cementitious waterproofing involves applying a mixture of cement and other compounds to create a barrier against moisture.
This method is frequently used in basements, bathrooms, and water tanks. It is particularly effective for below-ground applications.
Advantages:
- Easy to mix and apply.
- Ideal for wet areas, including foundations and basements.
- Highly resistant to water penetration.
Waterproof Coatings
Waterproof coatings are applied directly to external surfaces to prevent water absorption. They can be made from various materials, including silicone, acrylic, and epoxy.
They are typically used on walls, roofs, and facades to protect against water ingress.
Advantages:
- It can be used on various external surfaces.
- Enhances the aesthetic appeal by providing a protective, water-resistant layer.
- Low maintenance after application.
The Process Of External Waterproofing
External waterproofing involves applying various layers of waterproofing materials to the outside of a building. These materials form a barrier that prevents water from penetrating the structure.
The process typically includes excavation, surface preparation, the application of waterproof membranes, and drainage solutions to divert water away from the building.
Steps Involved in External Waterproofing
Excavation
The first step in external waterproofing is to excavate around the perimeter of the building or the area that requires protection.
This allows access to the foundation walls and provides space to apply waterproofing materials. The excavation depth depends on the type of building and the extent of the waterproofing required.
Surface Preparation
Once the area has been excavated, the surface of the foundation wall needs to be cleaned and prepared.
Repairing cracks, holes, or other imperfections ensures the waterproofing membrane adheres properly. This step is essential to prevent weak spots in the waterproofing system.
Application Of Waterproofing Materials
Various waterproofing membranes, including liquid membranes, sheet membranes, and bituminous coatings, can be applied to a building’s exterior.
The choice of material depends on factors such as the location, climate, and the level of protection required. The waterproofing membrane is applied to the prepared surface, creating a continuous barrier that prevents water from entering.
Installation Of Drainage Systems
External waterproofing systems often include drainage solutions such as French drains or drainage boards to keep water from the foundation.
These systems help direct water away from the building, reducing the pressure on the waterproofing membrane and preventing water from accumulating around the foundation.
Backfilling
Once the waterproofing materials and drainage systems have been installed, the excavated area is backfilled with soil.
Specialised backfill materials are sometimes used to improve drainage and reduce the risk of water pooling around the foundation.
Conclusion
External waterproofing is an essential investment for any building, protecting it from the damaging effects of water infiltration. Property owners can safeguard their structures against structural weakening, mould growth, and costly repairs by preventing moisture from penetrating the walls and foundations.
Several effective methods are available, such as bituminous membranes, liquid waterproofing, and waterproof coatings. External waterproofing enhances the longevity of the building and maintains a healthier indoor environment. Proper drainage systems strengthen the defence, ensuring a long-lasting and secure property.
FAQs About Waterproofing
How Do You Choose Waterproofing Material?
To select the appropriate waterproofing chemical, you will need to determine the density of the water that passes through the surface or the amount of water traffic on the surface of the material you want to waterproof.
How Long Does External Waterproofing Last?
The lifespan of external waterproofing depends on the materials used and environmental factors. High-quality waterproofing systems can last 10 to 20 years or more if properly maintained. Periodic inspections and maintenance will help extend the waterproofing’s life.
What Is The Best Type Of Waterproofing?
Polyurethane: Polyurethane is considered one of the best waterproofing materials. It can be applied seamlessly and penetrates the surface deeply and evenly. Thus, the polyurethane membrane will fill even the finest cracks in concrete, reducing its water absorbency capacity.
How Can I Tell If My Home Needs External Waterproofing?
Signs that your home might need external waterproofing include water seepage in the basement, damp patches on exterior walls, cracks in the foundation, and mould or mildew growth. Poor drainage around the home indicates the need for external waterproofing.
How Can I Maintain My External Waterproofing?
Regularly inspect the exterior of your home for cracks, leaks, or signs of water damage. Keep gutters and downspouts clear to ensure proper water drainage. Periodically check the waterproofing materials for wear and tear and reapply them when necessary to ensure continued protection.
