Comments of chapter undefined of My Kingdom Building System

Question, how do the village blueprints work. I.e. is lvl 2 just lvl 1 expanded/existing buildings upgraded or do they have to take down all their work and reconstruct from scratch? I ask from an optimal layout perspective as to whether a level 1 village will be as optimal as a level 2 village etc hence may need to be reconstructed. Though I gather if so it will be done in such a way it can be modulated into separate parts.