I have a 6’ x 6’ shed with a gable roof. When I bought it a few years ago, I had the option of paying extra for some pre-felted roof panels that went over the t&g roof. I had reservations at the time as it just looked like plywood with felt stuck on just the top face - nothing covering the ends or sides. Of course, water has completely ruined at the top and sides and it’s looking a right mess although it’s not leaking inside because of the t&g. Anyway, simple question, what to replace it with? Take the panels off and just felt on top of the t&g? Make up another couple of panels with ply and refelt them including the edges this time? Cold tar adhesive? Felt tiles? Anything else? It’s basically just two panels approx 6’ x 3’4”.