Corrosion Assessment — Multi-Storey Car Park
Surrey
4,200m²
Deck area surveyed
35%
Repair area reduction
£2.4m
Programme value
The Challenge
Comprehensive NDT investigation of a 1970s multi-storey car park to assess chloride-induced corrosion risk across all decks and inform a £2.4m refurbishment programme. The client needed objective condition data to challenge an overly conservative repair specification and avoid unnecessary concrete removal.
What We Did
Half-cell potential survey across 4,200m² of deck area, carbonation depth testing at 48 locations, and chloride profiling at three depths (20mm, 40mm, 60mm) at 24 sample points per deck. Defect mapping and condition grading delivered for all 6 decks, with corrosion probability zones plotted to 1m² resolution.
The Outcome
Half-cell readings confirmed active corrosion in 18% of the surveyed deck area — significantly less than the 53% assumed in the original repair specification. Chloride levels exceeded the 0.4% threshold at 40mm depth on the top two decks only. Survey data directly reduced the repair area by an estimated 35%, cutting unnecessary concrete removal and saving significant programme cost against the original budget.
Project Details
- Location
- Surrey
- Service
- NDT Corrosion Survey
Related service
Corrosion Surveys & Half-Cell Potential MappingHave a similar project?
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