Dimensions are only the start
A 24x30 pad and a 24x30 building slab may look similar on paper while carrying very different requirements based on finish, thickness, load, and intended use.
Site access and drainage can move the numbers
If the site is tight, sloped, or needs extra prep, that changes the path quickly. Those notes help keep early pricing discussions more realistic.
Talk about the building at the same time if needed
When the slab and structure affect one another, it is usually smarter to start them together than to price each piece in isolation.