If you need to do more than-saturate the stucco and end up with a drinking water location or two, use an oil primer in the spray can, to dam the stain. The cans feature tops specially built to spray ceilings. I'm not a professional. Just learning as I go and http://andrescttrp.blogpostie.com/18988595/a-simple-key-for-cost-to-remove-popcorn-ceiling-and-retexture-unveiled