What we found on site
The 8,500 m² reservoir lining had reached end-of-life: cementitious coatings were debonding in sheets, hairline cracking allowed chloride ingress into the concrete substrate, and active seepage was recorded at the construction joints.
The authority needed the asset back online before the summer irrigation peak — a fixed 14-week window — with zero compromise on potable-grade compatibility and a long-term warranty position.
Site logistics were tight: a single access shaft, restricted ventilation, and parallel works by mechanical and instrumentation contractors meant phasing and air quality had to be engineered from day one.
Technical Comparison: Substrate remediation vs. High-build polymer protection
From survey to handover
Condition survey & lining strip-out
ICRI-compliant moisture and pull-off testing mapped substrate condition. Failed lining was removed by ultra-high-pressure (UHP) water-jetting to expose sound concrete without micro-fracturing the parent matrix.
Concrete repair & joint detailing
Chloride-contaminated zones were cut out and reinstated with R4 polymer-modified mortars. Construction joints were routed, sealed with hydrophilic strip, and overbanded with a flexible polyurea detail coat.
Primer application
A two-component, low-VOC epoxy primer was rolled at 250 g/m² to seal porosity and develop the bond coat for the polyurea topcoat. Adhesion was verified to ≥ 2.5 MPa via dolly pull-off.
Pure polyurea spray application
Pure polyurea was applied via GRACO Reactor plural-component spray rigs at 70 °C / 2,200 psi, in passes to a nominal 3 mm DFT. The system fully cured within minutes, allowing continuous progression across the surface.
QA/QC & handover
DFT readings, spark/holiday testing, and adhesion checks were logged across a 5×5 m grid. Documentation included full traceability per batch, witnessed sign-off, and a 10-year system warranty.
System breakdown
Pure polyurea topcoat
Seamless, monolithic 3 mm membrane with >800% elongation — bridges substrate movement, eliminates laps, and resists hydrostatic pressure.
Epoxy bond primer
Low-VOC, two-component primer that penetrates concrete pores and develops mechanical and chemical adhesion to the polyurea.
Joint & detail system
Hydrophilic strip + flexible polyurea detail coat at all construction joints, penetrations, and corners — engineered to absorb cyclic movement without compromising the membrane.
- Membrane
- Pure polyurea, 3 mm DFT
- Tensile strength
- ≥ 18 MPa
- Elongation at break
- ≥ 800%
- Cure time (tack-free)
- 10–30 seconds
- Service temperature
- −40 °C to +120 °C
- Equipment
- GRACO Reactor E-XP2
Gallery
“TEXSA delivered a complex strip-out and relining inside a single summer-peak window. The documentation pack and the finished membrane both set a benchmark for our future reservoir programme.”