Similar problem with Bees
When I was a kid we had a similar problem with a swarm of wild bees getting into the wall of our house through a gap in the weatherboards. My dad waited until after dark when the bees had all quietened down and then put about a quarter of a phostoxin tablet into the wall through the gap the bees were using as their entrance. It got rid of the bees quick smart, we almost had to leave the house as well.
Phostoxin is a substance that dissolves on contact with moisture in the air to form phosphine gas. Back in the 70's we used the stuff on the farm for gassing rabbits. We would fill in all but one of the holes in a rabbit warren, chuck a tablet down the one remaining hole, and then quickly fill in the last hole. Taa... daa... no more bunnies.
I'm not sure whether you can still buy phostoxin tablets over the counter but they were good for getting rid of rabbits and bees. I'm sure it would work on wasps as well.
Regards,
Mirboo.