We live in a fairly new townhouse complex (Calgary). I discovered some small holes dug underneath the concrete porch, and when I stepped on the surrounding earth, it sank fairly easily, about three inches. I assume that there is a mouse nest underneath the porch. I did some light reading and will be buying some mouse traps to line the garden area. Will packing the area underneath the concrete porch with loam/dirt be enough to prevent a future infestation? Mike.
It is common for backfilled soil around a new structure to settle. Rodents could easily burrow into this soil and packing it down will not make any difference. If you have a rodent problem you should place traps in an animal and child proof bait station. You could also call a local professional for help.