First time posting to the forums and relatively new member... Two weeks after we washed a customers house they had a contractor come in and put a microwave vent through the wall. The contractor told the customer that there is moisture between the siding and the insulation and has the customer concerned. The contractor said the customer does not have Tyvek\moisture barrier and told the home owner that our low pressure spray has caused the moisture behind the siding in their walls and will result in mold. We do follow the lay of the siding so we do not spray into the overlap of the siding and we only use the soap nozzles, never using high pressure on the house. Has anyone else had a homeowner concerned with moisture behind the siding after a wash? If so, how was the concern resolved? Thanks in advance.