I just purchased a new walkout ranch with a poured foundation. The foundation has three hairline cracks in them: two (one on each side of the house) from the cement ledge down to the floor and the other from the hole where the water pipe comes into the house. The builder has come over twice and plastered some goop on the cracks from the inside, but they continue to leak whenever we get any rain. Does anyone know of a permanent solution to this problem? Is there something I can do myself or do I need a professional? I would like to finish the basement this winter, but am wary of doing anything until I am assured that this problem is fixed.