If the water is literally 'running' through an internal wall there may be a structural problem, leaking pipe, roof or gutter that needs investigation & attention first. No internal wall should have water running through it and whilst this product will waterproof, the problem may be transferred somewhere else in the structure.
However once this issue has been investigated and if a waterproof coating still required Sika Waterproof Coating should be applied to damp but not wet substrates.
The full preparation guidance is as follows:
All surfaces must be clean and sound. Use SikaÂ® Concrete Repair Mortar to repair any existing cracks and fractures before applying SikaÂ® Waterproof Coating.
Remove all loose material, dust and any previous coatings (plaster, paint, bitumen, oils etc).
Wash down with a water jet to clean and dampen surface. Always apply to a damp, but not wet substrate.