Also, the corners don't meet exactly. When mitering the corners in a home that is 15 years old, is this common due to settlement, etc. I would imagine that unless the corners are perfect you won't have a perfect meeting of the two pieces of chair rail. True? To fix this is it typical to apply calk or wood filler to the gaps? Also, the gaps that are along the top of the rail (where it meets the wall) - use filler for those too?