Why do all my Wall Heights default to 20'-0" ?

Thanks to CADDIGEST for posting this tutorial ! Wall heights actually don't always default to 20'-0" but they do default to the last height used if the Top of the wall was unconstrained. Always check the options fields at the top of the screen before you draw the wall. Note the Height fields. Here you can constrain the wall height (top) to a Level - or you can make the wall unconnnected (unconstrained) and set an unconnected height. The default is 20'-0". Once you set this, it will default to that height until you change it. It will also remember the last height you used even if you save the file and re-open it later. If you constrain the top of the wall to a Level, the field that says 20'-0" will be greyed out. After you start the wall tool but before you draw the wall, click the 'Properties' button and have a look. You have a wall 'Base Constraint' and wall 'Top Constraint'. The Base Constraint must be to a level and defaults to the level of the plan you are currently in. The Top Constraint can be to a Level or Unconnected. (check the pick list) If you set it to Unconnected (which is the default) it uses the last wall unconstrained height that you used. ie: 20'-0". Both constraining methods for Base and Top have the option to have an Offest from that Level. This can be a Positive number (above) or a Negative number (below). For example, this comes in very handy when you want to draw a wall that goes from 1'-2" below the level to 2'-6" above a certain level. The Unconnected Height shown in the wall Properties dialog box (13'-8" greyed out) is the total distance from Top to Bottom including offsets . I hope this helps clarify what determins the wall heights.