With a lack of adequate hardscape tools in Revit, many firms and individuals have taken to modeling hardscape with a variety of other families. Two of the most popular hardscape alternatives are Floors and Roofs. They are quite similar in their structure and they can both be modified by sub-elements.
When I was first introduced to the concept of modifying sub-elements it was actually via a Roof. As I have seen the topic discussed and presented, it seems like Roofs are quite popular among architects and structural engineers, perhaps because they are more familiar with shape-editing Roofs. But after using both Floors and Roofs for hardscape, I have found Floors to be the better option.
Here are the reasons why I use Floors for my hardscape (and not Roofs):
1. Floors push down, and not up. This may be fine (or even preferable) if you are working on a roof deck or some other landscape above structure. But if you change the structure of a Floor (left) and Roof (right) from 6″ to 24″…
Then the sub-element elevations on the Roof are no longer correct.
This is fine if you anticipate this with your workflow, but for most landscape workflows, you want those sub-elements to stay at their specified elevations.
2. Floors can host Level-based families (Roofs cannot).
This is something that I did not realize until quite recently, and it is the biggest deal-breaker for using Roofs. I need to be able to host level-base site families onto hardscape.
3. Fascia does not work on curved, sloping edges. One of the biggest reasons people seem to use Roofs is because they can create curbs with Fascia (or Gutters). But if you have a curved, sloping edge Fascia doesn’t work.
Neither Fascia, Gutters, nor Slab Edges can be created along curved, sloping edges of either Roofs or Floors. I have heard of firms using Fascia to create curbs, but I guess they do not have curved and sloped edges(?). Fascia can be created along a sloped straight edge (unlike Gutters or Slab Edges which cannot exist along slopes).
If you want to create a curb along a sloped, curved edge you can create an In-Place Curb.
4. Categorically, Floors make more sense. This may seem like a little thing, but it is important for your model to be understandable and accessible across multiple users. And when taken with the first three points, I see very little reason to use Roofs for hardscape.
But that is just my opinion. Do you have other reasons for using Floors or even Roofs?