Seek support for part of a house (5)
I believe the answer is:
lobby
'a house' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for lobby that I've seen before include "waiting room" , "Seek to influence (a legislator)" , "Solicit" , "Hallway; seek to influence" , "Shy" .)