OK, the correct way to trim the intersection of the ceiling and wall, is not with J channel but with F channel. The F channel is like 2 J channels in one. You affix the F channel in the corner and it provides a channel for both the wall and ceiling. Now for the wall to floor intersection, I believe the trim is called rat guard. Basically it's NOT a channel but a piece of trim that the sheet metal just sits on. You don't want to use channel on the bottom because you've already got channel at the top. If you have channel at both top and bottom, there's no good way to get the panel installed. Well, if you had the panel cut exactly, maybe you could get it to slide up, in, then down, but there's always a good chance you'd come up short... Besides, you don't want J channel on the floor with the J sticking up because it will collect dust and dirt, sawdust, etc.
Because the panel just sits on the "rat guard" you could simply use a piece of wood painted to the color of your choice. The wood would have to be 1" or more thick though because the ribs are about 1" so you can't use a 3/4" board...
You can get the F channel trim and rat guard trim at the same place you buy your liner panel at.
Oh, and you'd also use the F channel at the corner of two walls.
Brian
