Substantial alterations or substantial improvements to the thing held in indivision may be undertaken only with the consent of all the co-owners.
When a co-owner makes substantial alterations or substantial improvements consistent with the use of the property, though without the express or implied consent of his co-owners, the rights of the parties shall be determined by Article 496. When a co-owner makes substantial alterations or substantial improvements inconsistent with the use of the property or in spite of the objections of his co-owners, the rights of the parties shall be determined by Article 497.
La. C.C. § 804