[jimcol]

Although ours' is a different model our large slide sags in the middle something less than an inch. Has been that way since brand new. In 5 plus years it hasn't gotten any worse and the rubber swiper still makes contact with the roof. Never had a problem with leaks or anything. I thing that is just the nature of the beast. To stiffen it in the build process would definately add weight and or expense. Jim