Skunks are excellent diggers and continuing the barrier at a 90 angle makes it much more difficult to dig under. Backfill the area with dirt. Repair siding and holes in buildings. Place wood or wire screening around the base of porches and buildings as a prevention skirt. Eliminate piles of rock or debris and stack woodpiles neatly to eliminate holes.
Skunks can become trapped in window wells.
This will act as a ramp if it is not too steep. Try to keep it at less than a 45 angle. To put the board in the well, approach slowly and keep low and out of sight. Retreat if the skunk stamps his front feet or raises his tail and try again later. Keep all pets and people away and the skunk will leave on its own, usually after dark.