How To Waterproof A Concrete House?

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    When building or renovating a concrete house, ensuring proper waterproofing is a step that can save you from costly repairs and long-term damage. Water infiltration can weaken the structure, cause mould growth, and reduce the home’s overall durability. 

    This blog is dedicated to providing practical, easy-to-follow steps for protecting your home from the damaging effects of moisture. From surface preparation to material selection and ongoing maintenance, you’ll find detailed guidance on keeping your concrete house dry and secure for years.

    Let’s get straight to the point.

    To waterproof a concrete house, inspect and prepare the surface, clean and seal cracks and joints, and choose a waterproofing method like liquid, self-adhering, or cementitious waterproofing based on your needs. 

    Apply the chosen material following manufacturer guidelines, ensure proper drainage, and regularly inspect for maintenance. Key materials include polyurethane or silicone sealants, waterproofing membranes, concrete repair products, and admixtures. 

    Focus on vulnerable areas like the foundation, roof, and low-grade walls, use multiple layers, and apply waterproofing beyond the required areas for extra protection.

    Steps To Waterproof A Concrete House

    how to waterproof a concrete house

    1. Inspect And Prepare The Surface

    Before applying any waterproofing materials, it is critical to inspect the concrete surface thoroughly. Proper surface preparation ensures the waterproofing materials bond well and effectively prevent water infiltration.

    • Look for visible cracks, joints, and weak spots: Examine every concrete section, paying special attention to areas around windows, doors, and corners where leaks are more likely to occur.
    • Clean the surface properly: Use water and a suitable cleaning agent, such as trisodium phosphate (TSP), to remove dirt, grease, mould, and debris hindering waterproofing adhesion. Pressure washing may also be used to clear stubborn grime.
    • Allow the surface to dry completely: Moisture trapped under the waterproofing layer can cause adhesion problems and reduce effectiveness.
    • Key Tip: A thorough inspection can help identify potential weak points early, preventing costly repairs later.

    2. Repair Cracks And Joints

    Water can easily seep through cracks and expansion joints, so sealing them before waterproofing is essential. This step prevents future water damage and ensures the waterproofing material adheres correctly.

    • Seal expansion joints with high-quality polyurethane caulking. This material remains flexible as the concrete expands and contracts, preventing water entry.
    • Large cracks (wider than 0.6 cm / 1/4 inch): Use a concrete patching compound to fill and seal the gap. Large cracks also require mesh reinforcement for added durability.
    • Smaller cracks: Silicone sealants can be used as they provide a waterproof and flexible barrier. Ensure the cracks are clean and dry before applying the sealant to ensure proper adhesion.
    • Key Tip: To reinforce the structure, use a crack injection method for hairline cracks, especially in basement walls.

    3. Choose The Waterproofing Method

    Several waterproofing methods are available, each with its pros and cons. Select the best option based on your budget, the house’s requirements, and the local climate.

    Liquid Membranes

    Liquid waterproofing membranes are applied with a roller, spray, or trowel, creating a continuous waterproof layer over the concrete.

    • Advantages: Economical, easy to apply, and easy to cover irregular surfaces.
    • Disadvantages: It requires careful application to ensure even coverage, and thickness control can be challenging.
    • Tip: Apply multiple layers for added protection and ensure even thickness (about 60 mm).

    Self-Adhering Membranes (Peel-And-Stick)

    These durable sheets provide consistent thickness and are ideal for areas requiring strong, long-lasting protection.

    • Advantages: Easy to control thickness, highly durable, and tear-resistant.
    • Disadvantages: More expensive and time-consuming to install, requiring careful handling to avoid air bubbles.
    • Tip: Ensure proper overlap and smooth out air pockets to avoid weak spots.

    Cementitious Waterproofing

    A cement-based waterproofing compound that can be brushed onto the surface.

    • Advantages: It is simple to mix and apply, widely available, and suitable for areas that need a hard, solid barrier.
    • Disadvantages: Rigid, may crack if the concrete expands or contracts due to temperature changes.
    • Tip: This method works well for internal applications like basements and water tanks.

    4. Apply The Waterproofing Material

    Once the surface is ready, it’s time to apply the chosen waterproofing material. Proper application is key to ensuring long-lasting protection.

    • Liquid membranes: Roll, spray, or trowel on the membrane to the recommended thickness (typically 60 mm). Multiple layers may be required to ensure uniform coverage. Allow each layer to dry completely before adding the next.
    • Self-adhering membranes: Peel the backing and carefully place the sheet onto the concrete surface. Use a roller to press out any air bubbles, ensuring full contact with the concrete. Overlap each sheet by at least 6 inches to prevent gaps.
    • Cementitious waterproofing: Mix the compound according to the manufacturer’s instructions and apply it with a stiff brush. For extra durability, apply two coats, allowing the first coat to dry fully before adding the second layer.
    • Key Tip: Always follow manufacturer instructions for each product to ensure the best results. Mistakes in application can lead to water leaks and costly repairs.

    5. Ensure Proper Drainage

    Even with the best waterproofing methods, standing water near the foundation can cause pressure buildup and damage over time. Therefore, proper drainage systems are critical to the overall waterproofing strategy.

    • Install perimeter drains: French or other perimeter drainage systems can divert water from the foundation, preventing it from pooling around the house’s base. Ensure these drains are installed below the foundation level for optimal performance.
    • Use sump pumps: In areas with high water tables, sump pumps can help by removing excess water around the foundation and preventing it from infiltrating the house. Regularly inspect and maintain sump pumps to ensure they are functioning properly.
    • Grade the soil away from the house: Ensure the ground slopes away from the structure at a gradient of at least 5% (5 inches of slope per 10 feet of distance) to promote water runoff.
    • Key Tip: Combine waterproofing with drainage systems for the best protection, especially in areas with heavy rainfall or high groundwater levels.

    6. Inspect And Maintain

    Regular waterproofing system maintenance is essential to ensure the longevity of your concrete house’s protection. Even the best waterproofing systems can wear down over time, so periodic inspections are necessary.

    • Inspect for cracks or damage: Examine the concrete surface, joints, and waterproofing materials for any signs of deterioration. Check during seasonal changes when water exposure is more likely to cause damage.
    • Reapply sealants or waterproofing as needed: If you notice any wear, reapply sealants or touch up waterproofing materials to prevent leaks. Consider reapplying after 5–10 years for liquid membranes or cementitious coatings, depending on environmental conditions.
    • Key Tip: Regular inspections after heavy rain or during changes in season can help you catch potential problems early before they become costly repairs.

    how to waterproof a concrete house 3

    Materials Needed For Waterproofing A Concrete House

    1. Polyurethane Or Silicone Sealants

    Sealants are used to fill cracks and joints before applying waterproofing products.

    • Polyurethane Sealant: Best for expansion joints and large cracks.
    • Silicone Sealant: Ideal for smaller cracks up to 0.6 cm in width.

    2. Waterproofing Membranes

    Different membranes are used to create a waterproof barrier over the concrete surface.

    • Liquid Membrane: A polymer-based solution that can be sprayed, rolled, or troweled on.
    • Self-Adhering Membrane: A peel-and-stick sheet made of asphalt with a rubberised surface.
    • Cementitious Waterproofing: A cement-based mixture applied with a brush or trowel.

    3. Concrete Repair Materials

    For patching larger cracks, use a high-quality concrete repair mix.

    • Hydraulic Cement: Expands as it cures and seals cracks.
    • Concrete Patch Compound: Ideal for surface-level repairs.

    4. Waterproofing Admixtures

    Admixtures are additives that can be mixed directly into the concrete to make it waterproof.

    • Crystalline Admixtures: React with water and create a crystalline structure within the concrete, sealing pores and capillaries.

    Conclusion

    Waterproofing a concrete house is a critical process that ensures long-term durability and protection from water damage. 

    By following the essential steps—inspecting and preparing the surface, sealing cracks and joints, selecting the appropriate waterproofing method, applying the materials correctly, and ensuring proper drainage—you can safeguard your home against moisture intrusion. 

    Regular inspections and maintenance are equally important to keep the waterproofing system effective. With the right materials and attention to detail, you can keep your concrete house dry, safe, and resilient for years.

    FAQs About Waterproofing

    What Can I Add To Concrete To Make It Waterproof?

    Cement Mix is mixed with cement, just like water. The big difference is that the cement will be permanently waterproof with Cement Mix. Fortunately, there is an effective solution to this problem: Cement Mix. Cement Mix is a fluid that replaces water when mixing mortar or concrete.

    What Is The Best Product For Waterproof Concrete?

    Silicone sealants effectively protect and waterproof concrete. They also act as crack fillers and sealers, which can be applied to cracks up to one-quarter inch thick. Silicone or polyurethane sealant will be a resurfacing agent for already-protected concrete structures.

    Does Sealing Concrete Make It Waterproof?

    Penetrating sealants work 100% below the surface to protect and waterproof your concrete from within while remaining breathable.

    Can You Buy Waterproof Cement?

    You can now make your own at home, in the factory, or on the job through waterproof and water-repellent concrete grout or masonry cement. Cement mix replaces water in the concrete and cement mixing process.

    Should You Put Sealer On Concrete?

    You do not have to use a cure-and-seal, but it is important to seal your concrete. Sealing your concrete will protect it against damage and deterioration caused by water absorption and surface abrasion. In addition, sealed concrete is more resistant to cracking, spalling, and pitting.

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