I can relate to your story. Last year we kept getting wasps in our kitchen and could not figure out where they were coming from. We finally figured that they were coming in through the vent over the stove. DH check it and could see a nest at the top of the vent. When he went outside to double check, he could see them flying near the vent on the roof. He decided we really needed another fan over the stove anyway so he would just take that one out and put a piece of wood over it until he got the new one. When he tried to pull it out a whole section of tube was coming down with it and separated from the top section. So now the wasps had access to the attic area.
So he just left the vent in and was going to see about getting some one to take care of the wasps - yea right! That was last year and he has yet to get anyone to take care of it. He did tape off the inside end of the vent so no wasps get into the house, but who knows how many got into the attic.
Sunday I let the dog out and was standing outside for a minute with her and happened to see something on our bedroom window. I went down to see just what it was. A nice sized wasp nest being made by a couple dozen wasps.
So I went in and told my DH about it. While at Home Depot we picked up some spray and someone told DH to use it at night as they can not see in the dark. So first thing this morning while it was still dark, he sprayed it. He said he had to use about 1/2 the can of spray on it. Next he has to get in the attic to see what type of damage they have done up there.
Finally decided he better check since we are getting them again.
We usually have trouble with muddobbers making nests on our window frames, but the wasps are the worst. We have two cats and a white german shepard and the cats are notorious bug hunters. Especially our brat. She will sit and watch them and try and catch them. She loves watching birds too. She crouches down and talks to them. She goes nuts.
Hopefully the wasps haven't totally taken over the attic.