I do insurance restoration work, mostly in attics for Raccoon damage to insulation. Advice? Call a professional trapper and have them professionally removed. I have seen entire homes ruined by a single skunk. Insurance will not cover your home for removal of smell if somehow they spray near it or under it. They consider this "contaminants." And most policies specifically will not pay for "contaminants."
Most homeowners are usually not aware of the amount of damage a single skunk can do to a dwelling. One home in Chicago last year got sprayed by a skunk. It was a 550,000 home. The insurance covered the loss. (Rare) They spent tens of thousands of dollars trying to remove the smell, then tens of thousands on paint, then they tried removing the drywall. To no avail. Unfortunately, the peoples homeowners policy limit was reached and they were not able to get rid of the odor which permeated the entire dwelling. The insurance company spent some 550,000 dollars trying to remove the odor, which was also the policy limit. And now they have to live in a 4000 sq ft, 550,000 dollar home that reeks like skunk.
Cost of trapping a skunk on average; 125 dollars to set the trap and 65 dollars to take the animal away.
My suggestion is to call a professional trapper and get rid of it.