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Professional Waterproofing & Damp Proofing Solutions
Protecting Kenya's buildings from the foundation up. We provide advanced, guaranteed solutions for rising damp, leaking roofs, and basement tanking.
Why Professional Waterproofing is Non-Negotiable in Kenya
Water is the single most destructive element to a building’s structural integrity. In Kenya, where weather patterns fluctuate between intense tropical sunshine and torrential seasonal rains, the thermal shock and hydrostatic pressure exerted on buildings are immense. Without a scientifically sound waterproofing strategy, water ingress is not a matter of “if,” but “when.”
At Structrum Construction Limited, we distinguish clearly between Waterproofing and Damp Proofing, two critical but distinct disciplines. Waterproofing is the formation of an impervious barrier over surfaces of foundations, roofs, walls, and other structural members to prevent water penetrations. Damp proofing, conversely, is a treatment of a surface or composition of material to resist the passage of moisture in the absence of hydrostatic pressure.
Ignoring these issues leads to “Concrete Cancer”—the corrosion of steel reinforcement within your concrete—as well as toxic mold growth (Stachybotrys chartarum), peeling paint, efflorescence (salt deposits), and significantly reduced property value. Our mission is to arrest these issues before they compromise your investment.
Our Comprehensive Waterproofing Solutions
We utilize the latest chemical engineering technologies and application methods to deliver permanent solutions for every part of your building.
Flat Roof Waterproofing
We specialize in protecting concrete flat roofs from Nairobi's harsh thermal cycles. Our solutions prevent common failures like ponding water leakage and thermal cracking.
Technologies Used:
✓ 4mm APP Modified Bitumen Torch-on Membranes (slated for UV protection)
✓ Liquid Applied Polyurethane (PU) for seamless, joint-free finishes on complex roofs.
✓ Solar-reflective coatings to reduce internal building temperatures.
Basement Tanking
Sub-structure waterproofing is critical to prevent groundwater ingress due to hydrostatic pressure. We offer comprehensive BS 8102 compliant systems.
Our Approach:
✓ Type A: External self-adhesive membranes applied before pouring concrete.
✓ Type B: Integral crystalline waterproofing admixtures added to the concrete mix.
✓Fixture repairs
✓Type C: Internal cavity drain systems with sump pumps for existing damp basements.
Rising Damp Treatment
Rising damp causes unsightly peeling paint and health hazards like mold. We stop capillary action permanently without rebuilding walls.
Remedial Process:
✓ removal of salt-contaminated plaster up to 1.2m height.
✓ Drilling and high-pressure injection of Silane/Siloxane chemical creams.
✓ Re-plastering with salt-retardant additives to prevent hygroscopic salt migration.
Wet Area Waterproofing
Bathrooms, balconies, and kitchens are high-risk zones for leaks that damage ceilings below. We create a seamless "tank" before tiling.
Key Specifications:
✓ 2-component flexible acrylic-cementitious coatings.
✓ Reinforced angle fillets at wall-floor junctions.
✓ Specialized rubber gaskets for pipe penetrations and shower drains.
Pools & Water Tanks
Water retaining structures face dual pressure: keeping water in and keeping ground water out. We ensure structural integrity and hygiene.
Solutions Include:
✓ Non-toxic, potable water-grade epoxy linings for drinking water tanks.
✓ Cementitious crystalline slurry coats that withstand high negative pressure.
✓ Epoxy tile grouting for swimming pools to prevent chemical erosion.
Expansion Joint Sealing
Structural movement joints are necessary but often leak. We seal them while maintaining their ability to expand and contract.
Sealing Systems:
✓High-modulus Polyurethane (PU) sealants with backing rods.
✓ Polysulphide sealants for high chemical resistance.
✓ Hypalon bandage systems (Combiflex) for wide or damaged expansion joints.
1. Advanced Roof Waterproofing Systems
The roof is the first line of defense against the elements. In Kenya, flat concrete roofs (slabs) are popular for their utility but are notoriously prone to leakage if not properly treated. The primary cause of failure in flat roofs is thermal movement. Concrete expands during the hot Nairobi days and contracts during cool nights. Rigid waterproofing materials (like simple cement screeds) cannot handle this movement and eventually crack, creating pathways for water.
Our Solution: APP Modified Bitumen Membranes (Torch-on)
For large flat roofs, we utilize Atactic Polypropylene (APP) modified bitumen membranes. These are reinforced with polyester, providing exceptional tensile strength and elongation.
- UV Resistance: The mineral slate finish reflects UV rays, preventing material degradation.
- Elasticity: Can stretch and recover, accommodating structural movement without cracking.
- Thickness: We use 3mm to 4mm membranes, offering a robust physical barrier.
- Seamless Integration: Laps are heat-welded to create a monolithic surface.
Liquid Applied Polyurethane Membranes
For roofs with complex geometries or many penetrations (AC units, vents), sheet membranes can be difficult to detail. Here, we use liquid polyurethane. This cures to form a seamless, rubber-like skin that is fully bonded to the substrate. It eliminates the risk of water tracking beneath the membrane. We ensure a multi-layer application consisting of a primer, a base coat, fiber reinforcement mesh at critical junctions, and a UV-stable top coat.
The Structrum Process for Roofs:
- Surface Preparation: Mechanical cleaning to remove loose debris, oil, and moss. Correction of slope (screeding) to ensure zero ponding water.
- Angle Filleting: Creating a 45-degree sand-cement fillet at all wall-floor junctions to prevent membrane stress.
- Priming: Application of a solvent-based bitumen primer to ensure optimal adhesion.
- Application: Torching the membrane with precise heat control to melt the bitumen without burning the reinforcement.
- Testing: A flood test (ponding test) for 48 hours to guarantee water-tightness before handover.
2. Basement Tanking & Geotechnical Waterproofing
Basements are subjected to Hydrostatic Pressure—the immense weight of the water table pushing against the walls and floor. A simple paint job will inevitably blow off the wall under this pressure. At Structrum Limited, we engineer “Tanking” solutions that encapsulate the basement structure.
Three Types of Protection (BS 8102 Standard)
- Type A (Barrier Protection): The application of waterproof membranes to the external (positive side) or internal (negative side) surfaces. We prefer external application using self-adhesive HDPE membranes before the concrete is poured, ensuring the structure is protected from aggressive ground salts.
- Type B (Structural Integral Protection): Adding crystalline waterproofing admixtures (like Sika or Penetron) directly into the concrete mix. These chemicals react with moisture to grow crystals that block the concrete capillaries, making the concrete itself waterproof.
- Type C (Drained Protection): For refurbishment of existing damp basements, we install a cavity drain system. This involves a studded membrane on the walls that allows water to enter a controlled cavity and travel down to a perimeter channel and sump pump, where it is mechanically removed.
3. Eliminating Rising Damp & Salt Contamination
Rising damp occurs when ground water is sucked up through the porous masonry of your walls via capillary action, much like a wick in an oil lamp. This moisture carries hygroscopic salts (nitrates and chlorides) from the soil. Even if the water evaporates, these salts remain in the plaster, absorbing moisture from the air and keeping the wall perpetually damp.
Signs of Rising Damp:
- Tide marks on walls up to 1 meter high.
- Peeling or blistering paint and wallpaper.
- White, fluffy salt deposits (efflorescence).
- Rotting skirting boards and timber floors.
The Structrum Solution: Chemical DPC Injection
Traditional physical Damp Proof Courses (DPC) often fail or are bridged over time. We solve this by:
- Removing Contaminated Plaster: Stripping the wall back to the brick/stone up to 1.2 meters.
- Drilling & Injection: Drilling a series of holes at the base of the wall and injecting a silane/siloxane cream. This cream spreads into the masonry pores and cures to form a hydrophobic (water-repelling) barrier that stops capillary action dead.
- Re-plastering: Using a specialized salt-retardant cement additive (waterproofer) in the new render to prevent residual salts from migrating to the new paint surface.
4. Wet Areas: Bathrooms, Balconies & Kitchens
A leaking bathroom on an upper floor is a nightmare for the occupants below. The most common misconception is that “tiles are waterproof.” They are not. Grout lines are porous, and cracks in grout allow water to seep through to the slab.
The “Tanking Under Tiles” System
We implement a rigorous two-component cementitious waterproofing system under the tiles. This flexible coating (often acrylic-modified cement) creates a seamless tub.
- Pipe Penetrations: We use specialized rubber cuffs or sealant fillets around shower drains and pipes, as these are the #1 leak points.
- Vertical Upstands: The waterproofing is applied up the wall at least 300mm in dry areas and 2 meters in shower cubicles to prevent splash-over leaks.
- Flexibility: Our selected materials can bridge hairline cracks that occur due to building settlement.
Our Technical Methodology
Precision at every step ensures longevity.
1. Diagnosis
Moisture metering and thermal imaging to find the source.
2. Preparation
Surface grinding, cleaning, and crack repair.
3. Priming
Ensuring chemical bond between substrate and membrane.
4. Application
Multi-layer application by certified technicians.
5. Testing
Flood testing and warranty certification.
Why Structrum Construction Limited?
Waterproofing is a precise science. One small pinhole can compromise an entire roof. That is why choosing the right partner is critical. Structrum Limited brings years of structural engineering expertise to the waterproofing field.
Certified Applicators
Our team is trained by leading chemical manufacturers (Sika, Dr. Fixit, Basf) to apply their products exactly as specified.
10-Year Warranty
We stand by our work. Our comprehensive waterproofing systems come with a written guarantee for your peace of mind.
Material Science Expertise
We don't just "apply stuff." We understand polymer chemistry, selecting the right product (Acrylic, PU, Bitumen, Epoxy) for the specific environment.
Customer Reviews
Emily Waithera
My three bedroom mansion in Kirinyaga was completed by Structrum Construction Limited in the shortest time and with the professionalism that is worth mentioning.
Fredrick Kimutai
We consulted Structrum for a structural assessment before adding a second story, and their engineering team provided a clear, robust design solution. Their expertise instilled confidence, and the construction phase based on their plans went perfectly.
Elizabeth Wairumu
Structrum managed our full basement remodel, expertly coordinating the critical structural beam installation, intricate new plumbing runs, and flawless masonry work for the new fireplace. The quality across all trades was consistently high, resulting in a perfectly integrated and durable finished space.
Calvin Owino
Structrum's plumbing team resolved a persistent leak under our sink efficiently and professionally. Their diagnosis was spot-on, and the repair has been completely reliable ever since
Frequently Asked Questions
Why is my paint peeling off near the floor skirting?
This is a classic sign of Rising Damp. The Damp Proof Course (DPC) in your wall has likely failed or was never installed. Ground moisture containing salts is rising up the wall. The salts crystallize behind the paint, pushing it off. We fix this by stripping the plaster and injecting a chemical DPC cream.
Can you waterproof a flat roof without removing the existing tiles?
In many cases, yes. If the tiles are firmly bonded, we can apply a specialized primer and a UV-stable Liquid Polyurethane Membrane directly over the tiles. This saves the cost and mess of demolition. However, if the substrate is loose or waterlogged, we recommend stripping it down to the slab to treat the root cause.
What is the difference between Bitumen and Polyurethane waterproofing?
Bitumen (Torch-on) is excellent for large, open flat roofs. It is thick, tough, and cost-effective. Polyurethane (Liquid) is more expensive but superior for complex roofs with many pipes/AC units, as it forms a seamless skin without joints. PU also has higher UV resistance and elasticity compared to standard bitumen.
How long does a waterproofing system last?
A properly installed torch-on bituminous system typically lasts 10-15 years. High-end Polyurethane liquid systems can last 20+ years. The key factor is maintenance—keeping drains clear and repairing mechanical damage immediately.
My basement leaks only during heavy rain. Do I really need tanking?
Yes. Seasonal leakage indicates that the water table rises above your floor level during rains (hydrostatic pressure). Over time, this water flow will erode soil fines under your foundation and corrode the steel in your concrete walls. Ignoring it risks structural stability.