help with platforms

I have watched different videos showing raised platforms inside a room, higher than just one step. I saw a staircase that used a platform as a base and I saw a raised platform to make a simulated bunk bed. In my game however, platforms won't raise. When I raise the platform it is raising the room foundation instead, and the platform stays one step high. I can place them outdoors and raise them however high I want them, then when I try to place it inside the room it converts back down to the one step height. I tried with move objects on and off, same thing each time. What am I doing wrong? Thanks in advance if anyone can help !!