So my parents had their roof re-shingled back in 2003. I'm not sure what was re-shingled, whether it was the both the upper and lower roof, or just the upper roof (my father arranged the re-roofing and died suddenly/unexpectedly a couple of years ago). At any rate, the upper-most roof is starting to look a little "wavy". I'm assuming that's because the upper roof has 2 layers of shingles, and the lower one still has the single original layer. It looks like crap and my mother is trying to sell the house.
Just wanted opinions of whether or not she's looking at a complete tear-down and re-roof to fix the problem, or if this is purely something cosmetic that she could let "slide". There are no apparent leaks, no water staining on any of the ceilings on the 2nd floor, so I'm thinking the waviness is the result of the plywood warping underneath due to the weight of the 2nd layer of shingles. Obviously she's having a roofing contractor check the situation out, but wanted to get some opinions here so that some piker doesn't try to bilk her with a huge expense that may not be necessary at this point.