yeah theres plenty of threads. But just get some 2x4's, build up a flat rail, with some supports on the side. Put 3 1 in. pvc pipes on the top of the wood, then use liquid nails to glue them down. You can also screw them in at the ends. Pvc rails are great cause pvc is so cheap. It doens't crack that easily, but when it does and you cant slide it anymore, you just rip the old pipe off and put a new one down. It takes like 10 minutes.