We got a call because a customer was concerned about the exterior surface of their foundation wall, it showed signs of excessive pitting and spalling. Why does this happen anyway? Is it just poor concrete or is it something else?
It could be poor concrete. It could be how it was mixed, when it was poured, or when they pulled the forms. Concrete is supposed to be vibrated to get the air out, and sometimes they don't do that or maybe the home got the end of the batch. What normally causes this though, is the water sitting on the concrete and then freezing. It then breaks the concrete a little bit and then it gets these spall or pock marks. More water then sits on it and freezes again, and this can further damage the concrete. You do want to take care of it so that it does not deteriorate the foundation anymore.
So, the questions are: "Should your repair it, and when do you know it is time to repair it?"
It's a preventative maintenance issue. The sooner your repair it the better off you are and the less damage you will have. To answer the second question, to repair it we have to wire brush it and see how much we take off. Then we have to put additional adhesive material on it, called Milk. Then, we put a special masonry material over that which makes it smooth and the rain can't penetrate it. A crystallized quartz based material is then put over that and you're all set.