They have some crack or hole they are getting in at, and the size of the nest could be huge. I was running some cable through an attic with blown in insulation in a house, and found a nest about a foot wide and two feet high.
I would find the spot they are coming in, then come back at dawn in the morning with a couple cans of 30 foot wasp and hornet spray and hit the opening from a safe location, ie not under it, and no obstructions blocking a rapid exit.
You could also put up a wasp trap, but that is more control than eradicate.
Once you are sure all of them are dead, and I would repeat the process a couple different days, the entry point needs to be closed up, then "carefully" look for the inside entry point to your house.
Wasp/hornet spray has a tiny amount of poison in a mix of ether. Ether knocks them down, they can't fly, but may still crawl around, but you have to actually hit them with the spray, or its splash.