Imagery in The Odyssey
Homer uses imagery to create elaborate settings that become almost palpable to the audience. By putting so much effort into constructing space within this epic, Homer ensures that the audience has a vivid image of events within the story.
Note the differences between how the Cyclops is described as a lion compared to how Odysseus is described as a lion in Book B. Homer repeats the lion imagery, but he uses it in a more animalistic and barbaric way here to further contrast these two characters.
Homer may be emphasizing how large and well-defended the house is to prepare us for a later battle. It's also possible that he's showing off Odysseus' considerable wealth by saying that one building "keeps following on" after another, suggesting an entire complex, not just a house.