No under slab heat

[Narrow Path]

My car wash was built decades ago and doesn't have piping for under slab heat. Is there an alternative to busting out the slab and starting over?

 

[cantbreak80]

If there is enough headroom, a 4”-5” concrete overpour will work.
Secure ½” PEX tubing to 6x6 remesh and pour away.
You’ll likely need to excavate the entry/exit 3’-5’ to provide a smooth transition into and out of the bays. And, add extension rings for the drains.