Article 446 of the Civil Code of the Philippines

Art. 446. All works, sowing, and planting are presumed made by the owner and at his expense, unless the contrary is proved. (359)

This will made at the owners expense. If the building be large expensive or important, common sense may direct us to believe that the owner of the building is also the owner of the land. But this would not be the case for the under the principles of accession, we must still presume that the owner of the land is the person who erected the building.  This presumptions the article are rules of evidence or substantive law.