How to Fix a Sagging RV Headliner

I get a lot of questions from owners about issues with their rough materials, especially sagging. Now, manufacturers are going to build a roof that has either a rubber membrane on the top, or a fiber glass; used to be aluminum in the olden days. Then there'll be block foam insulation, a luan backer, and then either fabric, or a wallboard, like you would see on the side of this. Now the wallboard's the best, because you don't have to worry about the adhesive coming off and sagging, but you'll get a lot of echo inside. So you see a lot of manufacturers putting some type of a fabric material on the inside, on the ceiling portion. What happens is, that adhesive in there, because of the heat, because of the humidity, maybe even got a leaking roof at some point, where the water gets in and breaks that adhesive down, and that fabric starts to sag. The old vinyl, and it's still used, I say old, but it's still used today. The vinyl with a foam backer, as that gets older, and the temperature changes that you get in these RVs, that foam literally breaks down and crumbles, and it hangs down. So the way that I've fixed these in the past, it's kind of a cosmetic, you can come in and take all that fabric out, and put in new wallboard. I've seen people just literally nail or staple a whole new piece of paneling in the top. But that means you have to cut out all this stuff, match the light cutouts, the vents, the cold air return, all that stuff, and that's a lotta work, and then you've got an echo again. what I've done is, I find where the sag is at, let's say this area here was laying down, I run a cut all the way across, a nice even straight cut across the side, and then I get in and pull this fabric down, and that'll show you what's happening up here. We did this on my dad's Vectra that he had, and we pulled it down, and we had to go in and literally vacuum out all that loose foam inside. So we just took a Shop-Vac, vacuumed that out on both sides, and then reapplied an adhesive inside, that we got from a upholstery shop, and then pulled that fabric as tight as we could, up to the front, and actually went past the cut line. So then we recut it. I put a piece of paneling up, and a 2X4, just hooked up two of 'em out here, and just left that pressed against that for three or four days until it dried. Same thing on this side, you pull it back over, do the same thing, and cut a nice line. And then to hide that cut mark, We just put a nice decorative piece of trim, not quite this wide, but just to match the trim inside, of wood, and just ran it across. Because again, you got luan on the backside of this, which is a board, and I can just screw right into that. So I could put that... And I did that about every four to six feet, and it just looked like it was part of the ceiling. So that's something that you can do, to take a look at where those sagging marks are at, and what you can do to cut that, stretch it back in, put a little bit adhesive in it, press it up and let it sit, and then make a nice decorative cover over the top of it.