Pest control just got rid of 8 skunks under my concrete slab porch. This time, they got around the L-shaped wire barrier that I had installed 2 years ago when I had a skunk problem. They seem to return. From the lack of dirt on the outside, it would seem that there is space between (probably from settling) my concrete slab porch and the dirt it "used to" rest on. That must be how the skunks traveled under the concrete slab from the entry hole to the exit hole they dug under my L-shaped wire barrier 8 feet away. I am thinking of having a concrete firm mudjack the area under the porch, not to raise the concrete, as is the usual use of mudjacking, but to fill the burrow holes to eliminate the space (as I perceive it) between the porch and the dirt. I am concerned that the slurry may block up the drain tile I have around the house. When I tried to flood out the skunks on my own (left the hose on for 30 minutes), it only served to make my sump pumps turn on every 5 minutes. Is mudjacking something that is used to control skunks? Will they just burrow under the concrete? Is mudjacking solid enough to discourage skunks? Thanks for your help.

I am not familiar with mudjacking to prevent wildlife nuisance issues with skunks, so I contacted Bob Massey, a District Wildlife Biologist with the Illinois Department of Natural Resources. He provided this response:

Mud jacking is the use of heavy duty, specially designed pumping equipment, to fill gaps under various substrate. In addition to merely filling the voids, it can actually be used to lift pavement, sidewalks and even foundations. Generally speaking, a very flowable mix more akin to grout is used for this process. As such, extreme care should be used and a reputable contractor called and made well aware of all potential drain tile issues. You could also check out other materials, besides mortar, for the process. Urethane materials that expand to fill voids may also be used, and may not present the hazard filling the drain tiles. Although I have not heard of anyone using a contractor to "mud jack" for animal barriers, it is common for landowners to pour thin concrete mixes down holes around foundations to fill them to keep animals out. My guess would be expense is the primary reason this process is not used more often. The equipment and manpower would likely make the process cost prohibitive. The cost should be weighed versus the discomfort of this happening again in the future. Reinstalling the wire more securely and deeper than the first attempt would likely be much more cost effective and not chance filling the drain tile. Breaking out the current concrete and repouring may also be more cost effective than mud jacking, so several contractors should be called for each of the processes.

Follow up 2 to 3 years later: I installed a new barrier, this time larger and made out of rabbit cage wire. It keeps them from building a nest, but not from trying. The little buggers now show up and dig like crazy, trying to reach the old nest. Each time they dig around the area where there were entrances. But they dig a line 3 feet wide trying to get in and in several places. The wire keeps them out, but I need to stop the digging. This didn't happen in the 15 years before we had the skunk nest. I need to find out how to stop them from digging. My guess is they drawn to the old smell of the previous burrow. Is that correct? If so, would mudjacking (at least the outermost area of the porch) keep them away on the theory that concrete would cover whatever (smell, musk, pheromone, other) is driving them to the old nest? Tearing out and re pouring the concrete porch would be a major expense! Not going to happen. And I understand your concerns about filling up the drain tile mudjacking. By the way, I had a mudjacker come by ($550 quote)and he indicated he never had someone call him for a skunk issue. So I can't get the benefit of his experience, nor can I count on his knowing if a burrow is adjacent to a drain tile. How would anyone know? I guess I would like to know more about skunk burrows before considering that option. Are they likely to be just below the concrete slab, or do they dig 3 or 4 feet down? I read on your website that there are no "registered" skunk repellant, nor do frightening devices (sound, light, water) repel them for long. This seems to be confirmed by mixed reviews of repellants on amazon and other sites. I suspect I have more than one visitor so I am looking for a more universal solution.

Since this is an ongoing problem, you should talk with Bob Massey, IDNR wildlife biologist. Bob's number is (815) 476-7622.