Several years ago, I discovered a groundhog tunnel entrance inside an unused partition of a shed in the back of my 1/2 acre property. I didn't think anything about it, figured it was far enough from the house that it wouldn't be an issue. Live and let live, you're welcome for the free shelter, etc. Over the course of last summer and now, I've noticed a quicker-than-normal shifting of concrete patio slabs, cracks in the driveway and garage floor, the brick facade of the house pulling slightly away, front porch steps won't stay straight, and a couple dips in the backyard (where I had always assumed trees had been removed at one point) have grown substantially deeper.

Finding a groundhog hole yesterday snug up against my split level foundation and chimney made this all fall into place. I called a trapper to come and catch the things, that's currently in the process of happening.

However, I'm now very concerned about the underground network that I fear is unsettling my home, and I'm hoping for advice. I know the tunnels need filled in asap - but how can I find out just how extensive they are - how far they go, etc? Is there a pro I call for this, or do I really just pump as much filler material as the hole will take and hope that covers it?

Any advice is appreciated.