The vinyl strip does get sort of U shaped warped over time. Some times the ends pop loose and you just tuck them back in.
The vinyl can be replaced with new and it will hold stronger.
I would not necessarily use a screw to hold it in. If you have a real weak long section of if, I would replace it. Camping World or RV stores sell it.
If you want to keep the ends from popping out, I myself would use Dicro the rubber roof sealant. I have some in a tube, it will stick, and if I need to I can peel it back off some day to replace the vinyl. Iím sure there are other exterior caulking that will work as well.
If you do find yourself putting a screw in, use a good puddle of weather sealant over the screw hole as you screw it in. Again in my case more Dicor. This creates a weather proof seal as the screw goes in.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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