bdmowers

As you have been a painter I was hoping that you could answer my question about salitro (sp?).  We have had a lot of new construction done in our house and on some of the new plaster we have large areas of salitro appearing a year later, about twenty inches up from the floor.  The contractor told me that it is coming from the ground which I question because there is no sign of it at floor level above the baseboards.  We are about to dig it out ourselves and repair; do you know how to combat this problem.  We have a new roof and eves that carry away the rain water and sidewalks surrounding the house so I can't think that it is caused but damp but it is very frustrating.