Is there silicon chaulk on the roof? what is it around? Clear, white, chalky? Did you place it there? The reasons for my questions, I hate that clear chalk on the roof. You should be using self leveling "dicor" specifically made for RV roofs. This is good around vents, antennae, etc... I don't know too much about the type of roof you have, but make sure the sealant is conducive to the type of roof you have. Regardless, sealing your roof is half the battle. I lost a battle with a 30 foot travel trailer years back. Partly bad quality, partly my ignorance.