It was a spacious house, for the many people that came as soon as they heard of his homecoming, could be accommodated in that house (Mark 2:2). When eventually there was no more room not even at the door,
so that no one could enter or leave anymore, it becomes apparent that this was a dwelling that was built according to the Hellenistic-Roman style, with a vestibule or a foyer. Not only the room in which Jesus was, but also the inner court (aula or patio) and even the vestibule was filled with people. It is likely that this gathering took place in the early morning, following the rumour that Jesus had come home during the night.
It also becomes apparent that Jesus is not staying in a clay hut or a small house1, since it was possible to open the roof by removing some tiles (Luke 5:19). Then they still had to make a hole, probably by removing a few of the beams that supported the tiles, so that they could lower the bed through a wide opening.2
2 And many were gathered together, so that there was no more room, not even at the door. And he was preaching the word to them.