While durable, concrete is susceptible to damage if not properly waterproofed. Proper waterproofing prevents water from penetrating the surface, reducing the risk of long-term deterioration. Below, we’ll explore today’s most effective waterproofing techniques and materials.
Let’s get straight to the point.
Waterproofing concrete is essential to prevent water infiltration, which can cause cracks, mould, and deterioration.
Effective techniques include using waterproof concrete with built-in admixtures, sheet membrane systems, liquid-applied membranes, admixtures, elastomeric coatings, and silicone sealants.
Each method has pros and cons depending on the structure, environment, and budget. Key steps in the waterproofing process involve surface preparation, applying the material, and allowing proper curing.
Regular maintenance, such as inspections and spot resealing, extends the lifespan of impervious surfaces. Selecting the right material ensures long-lasting protection and reduces future repair costs.
Types Of Waterproofing Systems
When it comes to waterproofing concrete, there are several methods and materials to choose from. Each method has its advantages, but it’s essential to consider the structure, location, and environmental conditions to make the best choice.
1. Waterproof Concrete
Waterproof concrete refers to concrete with built-in waterproofing features. These admixtures are mixed into the batching plant’s concrete, making it water-resistant. These admixtures can include water repellents, densifiers, or crystalline admixtures. This method ensures long-term waterproofing without needing a surface barrier.
Advantages:
- Built-in waterproofing.
- Reduces the need for additional coatings or membranes.
- It can be used in both positive and negative side applications.
Disadvantages:
- More expensive than traditional concrete.
- Less flexibility in complex geometries or joints.
2. Sheet Membrane Systems
Sheet membrane systems have been a go-to method for waterproofing concrete for many years. These systems use a cold-applied, polymer-modified bitumen sheet applied to the surface of the concrete to form a waterproof barrier.
Benefits:
- Long-lasting and durable.
- Resistant to wear and tear.
- Excellent tensile strength and self-healing properties.
Drawbacks:
- Membrane application must be precise—no bubbles, bumps, or honeycombs.
- Vulnerable to damage during the backfilling process.
- Requires protective boards during installation.
3. Liquid-Applied Membranes
Liquid-applied membranes offer flexibility in application. They can be brushed, sprayed, or rolled onto the concrete, creating a seamless waterproof barrier. This type of membrane typically uses solvent-based urethane or polymeric asphalt.
Benefits:
- Ideal for complex geometries and tight corners.
- Creates a continuous waterproof layer.
- Quick and easy to apply.
Challenges:
- Thickness and evenness of application are critical.
- Requires a clean, dry surface to avoid adhesion issues.
- It can deteriorate under sunlight and foot traffic if not protected.
4. Admixtures
Admixtures are added directly to the concrete mix during batching, creating a waterproof barrier from within. These materials react chemically with the calcium hydroxide produced during hydration, densifying the concrete and reducing water movement.
Types of Admixtures:
- Water repellents: Create a hydrophobic layer but may not resist hydrostatic pressure.
- Densifiers: Increase the density of concrete but do not seal cracks.
- Crystalline admixtures: React with water to form crystals that block pores, preventing water infiltration.
Pros:
- Saves time and money by integrating with the concrete during mixing.
- Reduced need for additional membranes or coatings.
- Safe for the environment.
Cons:
- It could be better for structures subject to frequent movement, such as decks.
- It cannot fully prevent cracking from stress or settling.
5. Elastomeric Coating
Elastomeric coatings provide a flexible, durable barrier against water. These coatings can stretch and contract with the structure, making them ideal for areas with fluctuating temperatures and movement.
Benefits:
- Ten times thicker than standard exterior paint.
- It can be applied to various surfaces, including walls, roofs, and concrete.
- Long-lasting and aesthetically pleasing.
Limitations:
- Requires careful application and preparation.
- More expensive than traditional paints or coatings.
- It may need periodic maintenance, especially in high-traffic areas.
6. Silicone Sealant
Silicone sealant is widely used for waterproofing cracks and joints in concrete. It is a highly durable and flexible material that withstands extreme temperatures and environmental conditions, making it an excellent choice for sealing gaps in new construction and renovations.
Pros:
- Resistant to water, chemicals, and temperature changes.
- Suitable for both indoor and outdoor use.
- Easy to apply with a brush, roller, or sprayer.
Cons:
- It can take several days to cure, especially in humid conditions.
- Requires careful application to avoid mess.
Step-By-Step Guide To Concrete Waterproofing
Waterproofing concrete involves several key steps. Follow these procedures to waterproof your concrete surfaces effectively.
Step 1: Surface Preparation
Cleaning and preparing the concrete surface before applying any waterproofing material is essential. This ensures the product adheres well and provides the best protection.
- Sweep the concrete thoroughly to remove dirt, dust, and debris.
- Use a cleaner or etching solution to remove any remaining dust or oils from the surface.
- Rinse the concrete with a hose and allow it to dry completely—this may take up to 24 hours.
Step 2: Apply The Waterproofing Material
Once the surface is ready, the waterproofing solution can be applied. This process will depend on the material being used, but the general steps are as follows:
- Waterproofer application: Use a brush or roller to apply the material evenly across the surface.
- Ensure there are no pools of material left—spread it out evenly.
- If necessary, wait for the first coat to dry before applying a second coat.
Step 3: Curing And Aftercare
After the waterproofing material has been applied, it needs time to cure. The curing time varies depending on the product but usually takes 24–48 hours.
- Avoid heavy foot traffic for the first three days after application.
- Full curing, especially for vehicle traffic, takes 14 days.
- Avoid cleaning the surface with detergent for at least 30 days after application.
Tips For Maintaining Waterproofed Surfaces
- Regular Inspections: Conduct visual inspections at least once a year, focusing on areas exposed to the elements or heavy use. Look for signs of wear, cracking, or loss of water repellency.
- Cleaning: Keep the waterproofed surface clean and free from dirt, debris, and chemical spills. These can degrade the sealant over time. Gentle cleaning with mild detergents is recommended, but avoid harsh chemicals that can break down the waterproofing material.
- Avoid Pressure Washing: High-pressure washing can damage the protective layer on waterproofed concrete surfaces, especially for acrylic-based products. Stick to gentler cleaning methods to preserve the integrity of the sealant.
- Spot Resealing: In high-use areas such as driveways, entryways, or balconies, consider spot resealing as needed rather than waiting for the entire surface to show signs of wear.
Choosing The Right Waterproofing Material
Selecting the right waterproofing material depends on several factors, including the type of surface, environmental conditions, and the structure’s expected lifespan. Each project has unique requirements, and choosing the wrong product could lead to costly repairs. Careful consideration of these factors will help ensure long-lasting protection and efficient resource use.
Considerations:
- Climate: Different materials handle extreme temperatures and moisture levels differently. For example, some products may become brittle in cold weather, while others may degrade faster under intense UV exposure. It’s essential to match the material’s durability to the specific climate in which it will be used.
- Surface Type: Concrete, brick, and wood may all require different products. Using the right type of waterproofing material could result in better adhesion or adequate protection. Select a material designed for the surface type to avoid long-term damage or ineffective sealing.
- Budget: High-quality products may have a higher upfront cost, but they often save money in the long run through reduced maintenance. Cheaper materials require more frequent reapplication or may offer a different level of protection, leading to higher costs over time. Investing in the right product initially ensures better performance and fewer issues.
- Environmental Impact: Opt for eco-friendly and safe materials for children and pets if necessary. Many waterproofing products contain chemicals that harm the environment, so choosing non-toxic alternatives can reduce the ecological footprint. These materials protect your structure and contribute to a healthier living space.
Consulting a professional can help you choose the right material for your project. Experts can provide insights into the best products for your specific needs, ensuring that your waterproofing efforts are effective and efficient.
Conclusion
In conclusion, proper waterproofing is a crucial step in maintaining the durability and integrity of concrete structures, by selecting the right materials and techniques—whether waterproof concrete, sheet membranes, or liquid-applied solutions—you can prevent water damage and extend the lifespan of your construction.
Investing in quality waterproofing upfront, along with regular inspections and maintenance, not only protects your structure but also saves time and money in the long run. For the best results, always consider the specific needs of your project and consult with professionals to ensure the most effective waterproofing solution is applied.
FAQs About Waterproofing
Does Concrete Need To Be Waterproofed?
Waterproofing is required at concrete structures to keep moisture out of the facility and to protect the structural components of concrete and embedded reinforcing steel. If the integrity of the concrete is maintained, it can remain waterproof.
How Do You Waterproof Exposed Concrete?
The best approach is to waterproof the concrete using a penetrating hydrogel treatment. This treatment is ideally applied in two forms: as an admixture and spray-applied to the exposed face.
Can You Waterproof A Cement Floor?
We suggest you use Coo-Var Damp Shield. This two-part epoxy resin coating prevents moisture from rising and penetrating your concrete floor. Moisture can cause serious issues in the future, so this is an important step in waterproofing a basement floor.
Does Outdoor Concrete Need Sealing?
Outdoor concrete sealers are worthwhile and necessary. Experts who recommend having a concrete surface sealed do their customers a big favour. Without this extra layer of protection, concrete will absorb moisture and may begin to crack, spall, flake, and discolour, among other things.
