We have a 12 month old two story home with a flat roof and flat side walls . The top part of the house is rendered foam board. The top of the walls have been capped with colorbond capping. We are now getting stains down the side of the walls. We have cleaned the walls twice but it keeps happening. It looks like it is coming from underneath the capping where the capping comes down the wall (overhand of capping is about 4 inches). Should the capping be sealed between the capping and the wall or is there another reason why this could be happening? It is particularly bad in two areas however there are signs of dis-coloration on all the walls. Many thanks
