しんちく新築shinchiku
1.

The process of constructing a new building or home, often emphasizing modern designs or materials.

2.

A newly completed structure that has never been occupied before, typically associated with contemporary architecture or facilities.

Example:

家を新築中です。

しんちくいわ新築祝shinchikuiwai
1.

A celebration held to honor the completion or purchase of a newly constructed home, often involving gatherings with friends and family.

2.

A traditional custom in which guests bring gifts to express good wishes and congratulations to someone who has recently moved into a newly built residence.

3.

A festive occasion marked by the inviting of loved ones into a new dwelling to share joy and blessings associated with a fresh start in a newly built environment.