Mike,

To make a roof in DD:

The existing roof is defined by the corresponding floor polygon. Make a
copy of that polygon. Create a new external wall and define it by that
polygon. Now you can modify the polygon vertices to make your new roof
shape.

To make a new shell in Wizard, you can just copy the existing shell and
place it above by using the inputs on the first window. You can do it in
DD by copying all the components that make up the shell such as surfaces
and thermal zones, etc. and modify the elevation. Hope that helps some.

-Ryan