My condo is 2 stories (3 including garage) and built in 1995. The interior walls appear to have standard studs 16" OC. In the shared wall however, neither the magnet or knocking trick seems to work. When drilling, there appears to be a 1/4" or 1/2" sheet of wood under the drywall, then nothing. I managed to located one stud next to an outlet by drilling, 24" from the room corner. But no luck elsewhere. Can anyone shed some light on what may be going on? Thanks.

I have a wall that needs drywalled in the bathroom, and it can be done with two 8x4 sheets horizontal, butted up against one vertical (because the overall length of this wall is around 11'). I know that the recommended way is to hang it horizontal, but in a situation like this where the end piece could be hung vertical without a cut, is that the best way to go? (so instead of 4 seams, i would have 3, but am i sacrificing anything in terms of look or strength?) I know the seam will be a little odd too, it would have the beveled end of the vertical piece meeting up with the non-beveled edges of the horizontal pieces, but maybe one bevel is better than none?