Builder needed for restructural project.

I'm hiring a builder to restructure a building that one of my previous builders built for me. You will be working as a temporary substitute. What this commission pretty much entails is; there are two university buildings that are built for my game. One is smaller than the other. The large one is fully furnished and is about 3-4 times the size of the smaller one. What I need is a builder who can restructure the smaller building so that it is slightly larger (extend its exterior and expand the rooms inside) and take the interior furniture from the larger building and place inside the newly restructured building. The larger building is too large and is causing lag but the smaller building in my opinion is too small.

You can use all existing assets and models the only work I require from you is restructuring and organising the already made assets on the interior of the new building.

The ideal candidate will have extensive experience with interior design and architetural modelling in blender or any other 3d software. Any environmental work is also a plus.