OK, I know of a topper that is heavier than OEM fabric. it is tough awnings.com. I bought a used TT and the living room slide was torn. I looked up the replacement material in my catalog and it would cost almost $400. I was researching how to install tops on You tube and ran across the RV Geeks and they told how they got their material so I took that step and found toppers for both my slides for $270. and the material is much heavier. I think if you really want to make the topper water proof, open the slide and get a can of scotch guard and spray it. I used scotch guard on a tent and it worked wonders to keep the tent dry during a couple of elk hunting seasons.