The unusual vessel was washed ashore at Cross Beach, near Belmullet, Co Mayo.
Ballyglass coastguard checked it out after they were alerted by Malin Head Marine Rescue Service who was notified by a beach walker on Sunday.
A message pinned inside the boat from its builder, Rick Small from Thunder Bay, Ontario, said it was intended to be a gift to some homeless person in Canada who was not given a house by Newfoundland.
His note read: “I, Rick Small, donate this structure to a homeless youth to give them a better life that Newfoundlanders choose not to do! No rent, no mortgage, no hydro.”
Mr Small built the houseboat with lumber in Conception Bay, Newfoundland, last year.
He stuffed it with insulation foam for flotation then sealed the seams with tar.
He installed solar panels which power a small electric motor.
He only sailed it as far as Portugal Cove, a rural seaside community in Newfoundland, where he eventually abandoned it.
It’s a mystery how it travelled several thousand kilometres across the Atlantic to Co Mayo, but Mr Small is known for using the sun’s rays as power.
Last year he rode his solar powered three-wheeled bike 7,000km from British Columbia to Newfoundland. His average speed was about 27km/h per day.