Brother Smith -
When using the double sided 3M tape (VHB), the most common method of attachment is overlapping an inch. One very, very important word of note here: in order for everything to work out right, put your wall studs on 16 inch centers, and be SURE that when you order the aluminum, that you specify 49" width instead of the normal 48"!! If you don't, you will eventually have a seam with no stud to "back it up". I used the 48", and it meant that I had to add some wall studs to have a solid foundation to attach the sheets to. The 49" is available in white and other colors from a bunch of sources.