If you want to add a layer of insulation to an existing wall, you simply add an insulation skin to the composite wall. However, you cannot assign “New” status to just a single component of a wall – only to the wall itself.
To distinguish (for Renovation Filter purposes) the new insulation added to the original wall, the following workflow is recommended:
In this view, you want to show both the Existing and the New components of the wall.
This way, only the new part of the Wall – the insulation part – is displayed as “New” in this view.