White splotches on a new color coat.
We are building a stucco house near Pittsburgh, PA and have had trouble with finding information and products that are not synthetic. Our contractor has put on the scratch and brown coat and we are ready for our finish coat. We had tried some samples of colored portland lime mix, when they were applied they looked great, but a day later they all have a white coloring to them. They manufacturer said that the lime is coming to the surface but didn't offer any information to why that was happening. Our brown coat was applied two weeks ago. We did soak the wall before applying finish. We used a 3 part sand to one part portland/lime mix ratio. Do you have any ideas what is going wrong?
Yes, I have had this experience and probably an easy solution.
We had this problem with Caifornia powdered color sometimes in cold weather. If the temperature went down to about 40 the night after we put on the color finish coat, we sometimes got white splotches. In cold weather, say when it barely gets up to 50 degrees in the afternoon, any rain we would have in the next couple of days after we applied the finish could splotch the wall. The finish can take 2 or 3 days to set up real good in cooler weather. Meanwhile if it rains, the color can get washed out.
Prevention:
We put up temporary gutters and downspouts near roof intersections and where the wall is likely to catch water. I have even gone to Home Cheap-o, and bought short sections of gutters and end caps. Plastic tube landscaping type tube works fine. It doesn't matter if it has holes, because water runs downhill. This tube can be tied to the scaffold to direct water away from the house.