Originally Posted by Metalman
I have a leaky slide out on our 2015 Windsport. It occurred after about three years of use. The seal appears to be in great shape. It follows the contour of the roof and fits well against the roof. However, when it rains the awning above the slide out droops due to the weight of the rainwater. Water runs over the end of the awning, but some of it runs back under the awning and drops onto the top of the slide. I suspect that the rubber gasket could never seal a large flow of water, because there is very little pressure on the gasket to roof connection. The suggestion to tilt the RV slightly to encourage water to run away from the RV wall is a good one.
Yep...It works for me and as I mentioned it helps with the toilet as well.
One thing to consider, the slide awnings are NOT designed to keep water off the slide. The are designed to help keep debris off the top. Most trailers don't even have the toppers at all. It may also be worth checking to make sure some small twig or other debris isn't caught under the rubber seal. It wouldn't take much to allow water to get in.