La. Civ. Code art. 673
Current with operative changes from the 2024 Third Special Legislative Session
A landowner who builds first may rest one-half of a partition wall on the land of his neighbor, provided that he uses solid masonry at least as high as the first story and that the width of the wall does not exceed eighteen inches, not including the plastering which may not be more than three inches in thickness.
La. C.C. § 673