I live in a standard house with a slanted roof, vs. the flat roofed, leaky place I used to be in. For many years, there are almost no leaks in this '50s built house, but when it rains, and the wind blows from a certain direction only, I get a few drops of a leak and then I won't see it again for a year or more. It's only on north side of the house and I am on the West coast of the USA. What could be causing this? One roofer said this is common and happens to slanted roofs even when they are brand new.