Good afternoon Julia this is CJ and I provided a one time stinging insect service You pointed out a large yellow jacket nest behind the soffit above the deck. I gently lifted the soffit to expose more of the entrance into the nest. I heavily treated in and around this area with a slow acting low toxicity pesticide . As I explained, it should take about three days to see the amount of yellow jackets in the nest decrease. But if you see any activity on the fifth day (or any day after) give us a call back to retreat the area.