What is the ruling on reclaiming part of the sea opposite one's house and building on it, if neighbors have done something similar?

The Fatwa's summary: It is permissible to reclaim land from the sea as long as it does not result in harm. If it is reclaimed, it becomes the property of the one who carried out the reclamation, similar to the revival of barren land, due to the Prophet's (PBUH) saying: "Whoever revives a dead land, it belongs to him."