Apply small amounts of water over a short period until it has absorbed water deep into the wall.
Moist basement concrete wall repair crumbling.
The wall needs to be moist so that the old concrete won t leach moisture out of the mortar that you apply and cause the repair to fail.
Wash the walls with an acidic solution check on amazon to neutralize the salt completely and allow to dry for a few hours.
The walls have been painted and the wall is crumbing in several places behind the paint and salt like particles have formed.
If dry the moisture is originating elsewhere in the basement most likely from a basement shower easily remedied by installing a vent fan in the bathroom to direct steam outdoors.
The walls in my 63 yr old full walk out basement are crumbling in spots.
First off brush off any loose material from the basement walls.