1. I would cut back beyond the discoloration a little. I did this on our just to be safe as I considered that water damaged. WI had to tear out much more out, so it wasn't a big deal for me.
2. It depends on your siding. We have aluminum siding, so I needed enough butyl tape to fill the gaps in the siding. I actually put extra in the low spots and then put a strip on each side of the trim. What I was looking for is compressed butyl tape to push from the seam all the way down. I do the same thing when resealing windows.
3. Hang a picture??? When I cut the ceiling out in ours I tried to piece it together in hard to see areas. We have metal rails that run along the ceiling which made it easy and only have 2 12" seams showing. I used luan and the thickness was a little off from the original paneling, so I needed to sand the edge to get it to look OK. I'd fit it as best you can and then prime and paint the whole ceiling with a thick nap roller to hide it. Killz did a good job sealing over the wallpaper/paneling in our trailer and we painted the ceiling and walls.
woodtrucker wrote:
1. when cutting out the rot, is it necessary to cut back beyond the discolored wood even if it solid wood and not flaky? If it's ok, do I need to treat the wood with anything?
2. once reframed, the trim strip has to be reattached. I read on here that I should run two strips of butyl tape down each pc of trim before screwing trim back onto corners. Is this the norm?
3. any suggestions on the asthetics of fixing those ceiling corners. I'm doing both corners of camper. lots of rot in both corners.