Loop cut doesn't make a full loop I'm trying to model a room. For this I created walls around the room by basically extruding a cube three times and then attaching the ends. I want to now make a loop cut around the wall to make holes for windows and doors, but it doesn't work as expected. Basically I would like the loop cut to go all the way around the room, but for some reason it stops at one of the edges. See the pictures attached. Why does it do this and how do I fix it?
Try removing doubles in your mesh, you can easily do this by going in Edit Mode  pressing  W &gt; Remove Doubles.
You can also type Remove Doubles after pressing the  Space Bar.