BELOW-GROUND
TANKING
High-performance subterranean moisture defense systems for concrete foundations, lift shafts, and retaining walls, blocking high-pressure groundwater ingress permanently.
When Do You Need It?
Is Moisture Seeping Through Below-Ground Walls?
Groundwater exert constant hydrostatic pressure against subterranean walls. Watch for these warning signs to avoid major structural compromise:
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Efflorescence & White Chalky Salts
Groundwater leaches through concrete pores, depositing mineral salts that flake off, indicating active water path transmission.
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Damp Below-Ground Walls & Flooring
Damp patches, dark spots on concrete blocks, high subfloor humidity levels, or standing puddles at wall-floor cold joints.
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Timber Decay & Musty Odours
A persistent damp, earthy smell accompanied by rotting subfloor framing, mould growth, or structural corrosion.
Clear Breakdown
Our Below-Ground Tanking Systems
Bentonite Clay Sheets
Self-healing sodium bentonite geotextile membranes that swell on contact with water, creating an impenetrable gel barrier against retaining walls.
Positive Pressure Systems
Installing external sheet or liquid membranes directly to the outer concrete face prior to backfilling, keeping water outside the structure entirely.
Negative Pressure Sealing
Applying crystalline slurries and heavy-duty epoxy coatings to internal concrete faces when external excavation is impossible.
Crystalline Slurry Infill
Applying chemical treatments that react with free lime and water in the concrete, growing microscopic crystals inside pores to seal them permanently.
Job Examples
SUBGRADE PROJECT PROOF
Bentonite Clay Retaining Wall Seal
Remuera Subgrade Retaining Wall - Subgrade Membrane Installation
Negative Crystalline Block Slurry
Internal Retaining Wall Sealing - Parnell Townhouse
REAL CLIENT FEEDBACK
WHAT OUR CUSTOMERS SAY
ENQUIRE ABOUT BELOW-GROUND TANKING
Please enter your details. Our Auckland structural team will review your subterranean waterproofing scope and provide a fixed project cost.