Gently remove the old tape, purchase a roll of new tape from your dealer for a few dollars and cover the seams that have problems. I would also look for water leaks or stop making spagetti in the coach. I bought a towel rack from Camping World and installed it's mounts just outside the entry door so we can drop off the wet towels when we get back from the showers. I try not to boil water for anything but my morning coffee in my coach and it helps to keep the humidity levels down. If you camp a lot in warm states, the AC acts like a dehumidifier, but if you camp in the cold a lot and brew up Tea or coffee several times a day in the coach, the added humidity will get to the inside of your windows and your furnishings. This problem is not unique to Class B's, but it is more pronounced in smaller coaches, so anything we can do to help, will cut down on the problem. Just breathing, we each add about 1 quart of water to the air in our environment each day.