Geotechnical/ foundation design help?

I need some help for my senior design project. Basically, my team and I are doing the design for a building retrofit. The building roof needs to be replaced and we are going to design a new roof and reinforcements for the wall (which is masonry/bricks). They'll also be designing for new pavement for the lot and making improvements wit h storm water drainage. I'm responsible for the geotechnical component for our project. I have the soils report with boring logs and initial plan was to analyze the soil quality then design a shallow foundation for interior columns that will support the roof. However, there wont be any demolition of any sorts and the existing wall will actually be the one to support the roof. I'm confused on how to go about designing the foundation if we are keeping the existing walls, does anyone have any recommendations on how I can make improvements to the foundation or geotechnical components of this project?