In a cavity wall.
Wasp nest in attic vent.
If the nest is a hanging nest make sure you purchase a spray with a projectile shot so that you can completely cover the nest with it.
Wasps frequently build nests and thrive here as well.
Any breaches require sealing to prevent more wasps from entering.
If in a vent above ground level be sure to check that the vent does not serve an internal room of the house or your insecticidal wasp killer powder may enter the internal room when blown into the vent from outside.
Another very common place to find wasps nesting is in attic spaces.
Unlike a wasp a honeybee hives consist of many thousands of bees within just a few days a brand new colony may have a several sheets of honeycomb near or inside the vent or air duct.
Wear long sleeved shirts and long pants to help protect against stings.
Getting rid of bees in a vent or air duct is typically done by extermination or preferably live removal and relocation.
Wasps getting thru attic vents many of the ridge and other types of attic vents i ve seen have louvers with almost 1 4 inch slits that are big enough for wasps to get thru and they do not have any secondary screen.
Although the wasps are entering the air brick vent the nest may be up to 6 feet away under a building or it may be directly behind or to the side of the air brick ie.
The problem may initially seem minor with just a couple stray wasps but their numbers can quickly spiral out of control as the queen lays her eggs without the threat of natural predators.
Breaks in the insulation or small holes in the wood are common sources for wasp entry.
Spray the nest according to the directions on your spray.
Honey bees in a vent or air duct of a building or house can be difficult to get rid of.
If your wasps have built a nest on the floor of your attic bomb style wasp poisons work very well.
Famco sells a j vent with a 1 8 inch screen but wasps might be able to get thru that if they really wanted to.