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North London BeeKeepers
Bees in Chimneys.

General information:

We often get calls and enquiries about bees in chimneys and wall voids via air bricks ventilation holes and cracks.

In chimneys, if they are bees, it is most likly that a feral honey bee swarm has made a nest. Or that they are mason bees. It is also possible that wasps have built a nest.

1. Honey bees:

Once honey bees have made a home in a chimney flue or void, there is no way of removing them without demolishing the chimney, wall or exposing them in some way so the whole nest can be removed. This takes extensive and very costly building work.

They are unlikly to cause any harm or disturb you as the buildings occupant, so its often best to leave them undisturbed.

The only way of getting rid of them is to have them killed by a pest control company, permanant insect mesh should be fitted to pots and air vents used as entrances on the same bases cracks and holes should be filled and pointed, to exclude futher swarms occupying the void. The reason for this is that once a space has been used by honey bees as a home, they leave marker scents, that are highly attractive to bees and last for years.

2. Mason bees:

Mason bees will bore holes into the mortar if the pointing is defective on your chimney stack. They lay eggs in the holes they made, The emerging bees often bore holes to the inside of the stack encouraged by the warmth of air or flue gasses coming up the chimney, flue gasses make them dopey and they drop down the chimney A pest control company spraying the flue will not resolve this problem. The only permanent cure for this problem is to have your chimney stack repointed. Once remaining bees have emerged the problem should end permanently.

3 Wasps

In the uk wasps only make annual colonies, they are active from April to September, after this, the colonies die out, you are not likely to notice them until they have grown into a large colony of a few thousand. As beekeepers we don't generally del with wasps, its best to note where the wasps were flying from, and have the holes or cracks filled and pointed or air bricks screened in the winter months after the colony has died out to prevent further colonisation of the space.

(prepared by Martin May 2004 updated April 08)

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