Mold and mildew control can be tricky in the northwest. Mold inside of houses is typically a result of moisture build up as a result of poor or incorrect ventilation related to bathrooms and kitchens. Other causes can be poorly sealed foundations and compromised exterior siding, flashing or roofing. I have equipment to detect moisture, track the source, address the root problem and permanently eliminate the mold. Green exterior mildew is common on most parts of the house and unavoidable in certain areas, like where trees keep sunlight from getting through. Simply pressure washing and using some mold resistant treatment can keep it at bay, but unfortunately there is no permanent solution in this part of the country.