Bricks, Masonry, Asphalt and Concrete - Adding an Addition with Basement to a House on a Slab

I am considering adding an addition to my house which sits Ten feet above street level. I currently have no garage. I can build out 30 feet, and would like a 2 car garage, but also would like to add space to my first floor. I want to dig out and have the garage at street level. I believe this would be the same as adding a basement foundation. The house currently sits on a slab. Is this possible? Do i risk cracking between the old slab and new basement?

You need professional design help to prepare the permit drawings that will show how to support the slab an grade and tie it into the new garage/basement that is lower.

It is very doable project and would make efficient use of the land and existing structure.

However, it is not a DIY job because of the skills required and possible problems. - You could handle the work beyong the foundation and basic stucture.

Dick

Thanks Dick, I had no intention of doing this work myself, it is way above my pay grade, just wanted to determine the plausability. Thanks for the help. Out of curiousity, any idea what i might be looking at in terms of cost of the masonry? I'm just looking for a rough estimate, knowing that cost varies by area.