If you are a discerning home owner, who values quality materials, and would like to develop a Master Plan for your house, I encourage you to consult with an architect who specializes in home extensions, additions, renovations, and remodeling. 

A residential architect is used to working with the breadth of trades people that initially built your house and the others that keep it running safely. 

The first step of developing a Master Plan is to have your house measured and documented. Additionally, it is very useful and smart to have a recent survey of your property. Surveying is more of an art than a science. It is important to locate the boundaries of your property. Additionally, a survey can include the slope of your land, or grades as it is referred to in building lingo. This information is enormously helpful in determining how water effects your building during rain storms and snow melt. 

The next step is reviewing the local zoning and building codes. These codes sometimes tell you the limits your house can have. Zoning codes often tell you what kinds of use you can have in your home. Is it legal to have a home business?  The zoning people draw imaginary lines from your property line and call them SET BACKS. There are usually front yard setbacks, side yard setbacks, and rear yard setbacks. 

Other restrictions are the height of the building and sometimes the total gross area. 

Additionally, in some communities there are massing restrictions. 

Existing conditions is a term used by builders and architects to review what is existing, or is there on your site. The size, length, width and orientation are determined. Additionally, the actual condition  of your building will be reviewed. The home inspector, builder, or architect will review your building with a visual inspection. At this points, walls, floors, and ceiling are not typically opened up.