Is it possible to put a basement under a existing garage with a slab floor?

Yes, it is possible to put a basement under an existing garage with a slab floor, but it involves significant structural work. You'll need to excavate beneath the slab, which requires careful planning to ensure the garage remains stable during the process. Additionally, you may need to reinforce the garage's foundation and address any drainage issues that arise. Consulting with a structural engineer is essential for a safe and effective conversion.