noun, noun-modifying (irregular)
old building; old construction
Used primarily in real estate to describe older properties, often with a nuance of being dated or less desirable. Can function as a noun or prenominally.
この物件は築古ですが、リノベーション済みです。
This property is an old building, but it has been renovated.
築古マンションは家賃が安い傾向がある。
Older apartments tend to have lower rent.