“Why Is My Building Still Leaking After Waterproofing?”
- desrhodes
- 6 hours ago
- 5 min read
“Why Is My Building Still Leaking After Waterproofing?”
If you’ve already done waterproofing and your building is still leaking, you’re not alone—and it’s frustrating. You expected dry walls, dry roof slabs and peace of mind, but instead, you’re dealing with leakages, damp patches on walls, musty smells, or worse, actual water damage.
Some Categories of Waterproofing Failures
1. Walls Waterproofing Failures
Includes:
Basement Walls (below-grade)
Exterior Walls
Bathroom Walls
- Cause: Incorrect application of membranes, poor surface preparation, failure to seal joints and cracks, or the use of unsuitable products.
- Result: Water infiltration through the wall due to cracks or gaps in the waterproofing system.
- Symptoms: Damp patches on walls, peeling paint, mold growth, discoloration, and structural damage.
- Common Solutions: Use of high-quality membranes or surface applied crystalline waterproofing admixture (application of Krystol T1 or KMA(Krystol Mortar Admixture) from Concrete Logistics Ltd), proper joint sealing, and surface preparation before application.
2. Foundation Waterproofing Failures
Includes:
Foundation Walls
Concrete Slabs (underneath the foundation)
Damp-Proof Membranes (DPM)
-Cause: Lack of or improper application of damp-proofing or waterproofing layers, failure to address groundwater pressure, or inadequate surface prep.
-Result: Moisture rising from the ground or seeping through the foundation, leading to dampness in lower levels, basements, or floors.
-Symptoms: Rising damp, visible water stains on floors or walls, and mold growth.
-Common Solutions: Installation of membrane systems, and a proper dewatering system.
3. Concrete Roof Slab Waterproofing Failures
This includes:
Roof Gutter
Terraces
Roof Decks, Balcony & Patio
-Cause: Insufficient sealing around joints and penetrations, Improper or worn-out membrane installation, poor drainage slope, inadequate surface preparation .
-Result: Water infiltration into the structure beneath the slab, Leaks or moisture infiltration into the building.
-Symptoms: Leaking ceilings, water stains on the ceiling, pooling of water on the roof, visible cracking or deterioration of the surface.
-Common Solutions: Repair & restoration by using our repair systems including surface applied crystalline waterproofing and proper drainage installation
4. Swimming Pool Waterproofing Failures
Cause: Inadequate bonding of waterproofing membranes, poor pressure testing, or cracking due to ground movement or structural issues.
Result: Water leaks from the pool, causing water loss and potentially damage to surrounding structures.
Symptoms: Visible cracks, wet patches outside the pool, rapid water loss, and pooling water.
Common Solutions: Use of pool-grade membranes, regular inspections, and crack injection methods.
5. Wet Areas (Bathrooms, Kitchens, Showers) Waterproofing Failures
Includes:
Bathrooms (showers, wet floors)
Kitchens (wet areas near sinks)
Shower Floors and Walls
Cause: Failure to apply waterproofing materials before tiling, improper sealing of edges, or water pooling due to poor drainage.
Result: Moisture penetration behind tiles or fixtures, leading to water damage, mold, and structural decay.
Symptoms: Moldy walls, loose tiles, water stains on the ceiling below, visible leaks.
Common Solutions: Use of liquid membranes, cementitious waterproofing, and proper sealing of joints
So what went wrong?
Let’s break down the most common reasons buildings still leak after 'waterproofing' and what you can do differently moving forward.
1. Poor Workmanship:
Many times, the problem isn’t the waterproofing product it’s how it was applied. Waterproofing requires precision, surface preparation, and attention to detail. If it was rushed, skipped in places, or done without proper tools, water will always find its way in.
Quick Tip: Waterproofing is not just paint. It’s a system that must be applied correctly to work.
2. Wrong Product for the Problem
Not all waterproofing materials are created equal. Using surface coatings where integral waterproofing is needed (like for below-ground work) often leads to failure. For example, paints or bitumen might look fine at first, but they peel or crack under pressure over time.
3. Absence of Dewatering and Groundwater Control
If your building is below ground (basement, underground car park, etc.), waterproofing alone might not be enough. You also need dewatering—that’s the process of managing or removing water from the soil or foundation area. Without this, pressure builds up and forces water through any weak points.
4. No Waterproofing at the Right Stage
Waterproofing should ideally be planned before the structure is fully built. Many clients only think of it after they see leaks, but by then, it’s harder (and more expensive) to fix. That said, it’s never too late—there are still solutions surface-applied admixtures that can help)
5. High Water Tables
When a building is constructed in an area with a high water table and proper dewatering or waterproofing systems aren’t installed, groundwater exerts pressure against the foundation. Over time, this hydrostatic pressure forces water through cracks or weak spots in the concrete, especially if the waterproofing layer was poorly applied or missing entirely.
The result? Persistent leaks, rising damp, and even structural damage.
Case Study
Concrete Logistics Limited was called to repair and waterproof the roof slab of an office complex. Despite the initial application of a Bituminous Felt Membrane, the concrete slab experienced significant leakage, particularly affecting the penthouse floor where the Board Room and Top Management offices were located.
Solution Implemented:
Removal of Existing Materials: The team began by removing the existing tiles and the damaged felt membrane to expose the concrete slab.
Surface Preparation: Specialized surface preparations were conducted to ensure optimal adhesion of the new waterproofing materials.
Application of Waterproofing Systems: The exposed concrete surface was treated with the Krystol T1/T2 waterproofing system.
Crack and Joint Treatment: All joints and cracks were addressed using the Krystol Crack/Joint Repair System to ensure comprehensive waterproofing.
Pipe Penetration Sealing: The Krystol Pipe Penetration System was employed to seal areas where pipes penetrated the slab, preventing potential leakage points.
This comprehensive approach provided a permanent waterproofing solution, effectively resolving the leakage issues and protecting the integrity of the office complex's roof slab
Comparing Waterproofing Methods
Here’s how common waterproofing types compare so you understand why some fail:
Waterproofing Type |
Where It’s Used |
Common Issues |
Long-Term Performance |
Bitumen coating | External walls, low budgets | Peels, cracks | Medium |
Waterproofing paint | Bathrooms, walls | Cosmetic, short-term | Low |
Crystalline (e.g., KIM) | Concrete structures, below grade | Needs expert install | High |
Sheet Membranes | Roof decks, wet areas | Seams can fail | Medium |
Common Mistakes Builders/Homeowners Make
- Skipping surface preparation
- Thinking paint = waterproofing
- Not checking for water pressure buildup
- Hiring non-specialists for cost-saving
What You Can Do Now
If you’ve already done waterproofing and it failed, don’t panic. The key is to:
- Inspect and diagnose the actual source of the leak (Concrete Logistics Ltd can help)
- Choose the right waterproofing system for your specific structure
- Work with professionals who understand both above and below grade waterproofing systems
Repair & Restoration of Damaged Concrete Structures
We've established that various factors, including poor waterproofing, can damage concrete structures. Fortunately, these structures can be restored. At this point, integral waterproofing may no longer be an option for an existing structure. This is where repair and maintenance come in.
To address water damage, various waterproofing system can be used effectively to restore the integrity of the structure, depending on the type of damage
At Concrete Logistics Ltd, we offer a range of tailored repair systems designed to suit different types of concrete damage, ensuring long-lasting results and protection. Some of our repair systems include:
- Surface-applied crystalline admixture
- Pipe Penetration System
- Joints and Cracks Repair System
- Plug and Grout Repair System
Need Help?
We’ve helped homeowners, facility managers, and contractors across Lagos fix failed waterproofing in critical commercial, residential, industrial and institutional structures. If your building is still leaking, we’ll help you assess the issue and recommend the right solution—no guesswork.Contact us @ Concrete Logistics Ltd
27 Oyeleke street, Alausa, Lagos
08098961008
09086744444
09031401762
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