Start with conditions, not a product
Removing what's visible without addressing the leak, condensation, or drainage problem underneath just resets the clock until it returns.
Build a complete scope
- What is keeping it wet, identified before the cleaning is costed
- Whether cooled surfaces meeting humid air explain it without a leak
- The barrier around the work and how air leaves it
- What is removed versus cleaned in block or plaster construction, and why
- Verification afterward, and the humidity-control fix that prevents a repeat
St. Petersburg context
Along the waterfront, moisture problems often trace to seawall seepage or king-tide backflow; further inland, it's more commonly AC condensate lines or plumbing in an older masonry wall. St. Petersburg's flat terrain means neither situation drains itself the way it might in a hillier city.