Final answer:
Low-slope roof decks must enable water drainage to prevent damage and should not be completely flat. Supporting heavy vegetation and thermal conductivity are not primary concerns for these types of roofs.
Step-by-step explanation:
When it comes to construction and engineering of buildings, specifically relating to low-slope roofs, it is essential for the roof decks to allow for proper water drainage. This characteristic helps prevent water ponding and potential damage due to water infiltration. Roof decks should not be completely flat, but instead they should have a slight slope to guide water towards drains. Supporting heavy vegetation or having a high thermal conductivity are not primary requirements for low-slope roofs. Furthermore, taking into account topography and drainage is crucial as these factors influence soil erosion, runoff, and water infiltration, which are also considerations in building construction and landscaping. While the vegetation and the presence of elements like lichens may play a role in soil stability and erosion control, they are more related to the ecological aspect than to the structure of roof decks.