There is a truss that would deflect the load into your outside walls, and it is called a 'barn truss'
Basic principal is to deflect the load from a ridge beam through a king post into the outside walls. Span seems to be all right for that.
But unfortunatly there is not enough information to say if it would work.

And definetly have an engeneer check out your foundation. I coudn't agree more that you may run into big problems if you don't.