You may try and keep your trailer level even in storage if it wasn't i found on mine that if it's level it doesn't get any water in side i found this out after one side of my trailer settled into the dirt a little, i also think what is going on is that the slides only have rubber wipes on three sides and there is non on the bottom, i went out when it was raining one day and on my bedroom slide water was coming down the side of the slide and running down the bottom of the rails toward the inside if the trailer is off level most of the water dripped off but a little got inside, if it's level it just drips off to the ground, So I'm thinking on putting a wipe along the bottom to help with this problem just in case it's off level for some reason during rainy times.