A number of Builders try install detached garages on a concrete slab instead of placing the garage on a foundation wall with footings. I had a debate the other day with a fellow builder friend of mine. His argument was that it is less costly to build a detached garage on concrete slab and therefore saves the homeowner money....really?
Of course it is cheaper, but Trademark Construction believes that most homeowners would rather pay a little extra money to have their detached garage built on a solid concrete foundation with footings. Especially in the state of Wisconsin where the winter frost can be harsh and deep. Believe me, the frost will shift and heave everything and anything in it's path (just drive down a concrete highway in the winter as your car bounces up and down).
I have witnessed so many garages that other builders have built on a concrete slab that have excessive cracks in the floor, the floors are heaving, and/or the garage itself has settled and is leaning. The only thing Trademark Construction would built on a slab is maybe a small shed in the back yard.
Garages can be large and heavy, they are meant to have a foundation and footings under them so they will stay upright, the floor will not heave or shift, and they will be problem-free for a long, long time.