You could see if on the mortgage or any other paperwork related to the house, it has the name of the company that constructed the house and you could try contacting them. (Mortgage, conveyance records etc can be obtained from the EBR Clerk of Court 389-3975) Another option would be to talk to neighbors, the houses may have similar designs or they may know who built them. The real estate office that sold the house may know who built it.
You can also contact the City of Baton Rouge Permit and Inspection division 389-3205 to see if they have anything on file. If all else fails you could hire an architect to recreate the blueprints from scratch.
