Why wasps use air bricks
Air bricks are ready-made entrances. Behind them is a dry, dark cavity: the wall void or the space under a suspended floor. A queen only needs to slip through the vent in spring to find a perfect nesting site.
Vents near the ground are the most common, but wasps will use any air brick, including high ones on gable ends.
What is happening behind the vent
The nest itself is rarely in the vent. It sits in the cavity behind, growing through the summer. By late summer hundreds of wasps an hour can be using one small vent, which is why the traffic looks so intense.
You may also hear a faint crackling behind the skirting or through the floorboards. That is the nest growing, and it is normal.
Never seal an active air brick
The worst thing you can do is block the vent. Sealed wasps do not die quietly. They chew through plaster, skirting and floorboards to find a new exit, and the new exit is inside your home.
Do not squirt foam or spray into the vent either. It kills a few wasps at the entrance and angers the several thousand behind it.
- Do not block or tape over the vent
- Do not spray or foam the entrance
- Keep children and pets away from the wall
- Note which vent they use and call us
How we treat through the air brick
We apply the treatment at the vent itself, without opening up the wall or lifting floors. Returning workers carry it through the cavity into the nest, reaching the queen and the larvae.
Traffic at the vent usually drops within hours and stops within about 24. If the nest is still active after that, your free revisit covers a second treatment. One nest is £125, fixed.
Once the vent nest is dead
The dead nest in the cavity causes no harm and will not be reused. There is no need to open the wall to remove it.
If you want to stop it happening again, fit vent covers with a fine mesh in winter, once you are sure the nest is dead. Never fit them while wasps are active.
Air bricks nests: common questions
Will blocking the vent kill the nest?
No. It traps the colony and forces it to chew a new exit, often indoors. Treat first, then mesh the vent in winter if you want to.
Can the wasps chew through into my house?
Only if they are trapped or the nest is very large. An untreated, unblocked nest almost always stays in the cavity. This is why we say treat it, do not seal it.
Is an under-floor nest treated the same way?
Yes. Whether the cavity is in the wall or under the floor, we treat the entrance and the wasps carry it to the nest.