Bees In Your Brickwork? Count Your Blessings
There are several species of bees that can take up residence in crevices or holes in masonry, hence being known as ‘mason’ or ‘mortar’ bees. They look more like a wasp, for which they are often mistaken, and most varieties are harmless.
They are mostly found in sunny south-facing walls in pre-existing holes in bricks or mortar. They can also excavate small nesting burrows in soft mortar. They lay their eggs in the holes and then seal up the cavity with mud… nature’s miniature masonry re-pointers! The bees won’t generally destroy the mortar or brickwork, preferring to use existing cavities where available, although in extreme cases their tunnelling activity can weaken wall structures.
The following video shows a bee removing a nail from a wall, demonstrating its workmanlike attitude. The nail, inserted into an existing hole, was extracted by the bee to allow it access to a nesting site.
If a nest infestation occurs, the best solution is re-pointing of soft or hollowed-out mortar during late summer or early autumn, after the bee’s spring and summer activity. One inventive and environmentally positive action to consider during the repointing work is adding a bee nesting brick directly into the wall itself.
Bees are tremendous pollinators, aiding fruit and crop fertility far more than traditional honey bees. They are a double blessing, not only because of their benefit to gardeners and farmers, but also because they reveal weaker, poorly maintained areas in walls and mortar, pointing out areas that may need future attention after the bee’s natural life cycle.
“Although they are best known for causing trouble in walls, mason bees are also very active on roofs where they build their galleries between and under the tiles. In situations like this the bees cause very little if any damage, and should be considered less of a problem, unless large numbers migrate onto surrounding walls and mortar.
“Bees discovered entering or attacking the soft mortar of stone and brick walls are described as “economically important”, especially in cases where large numbers of these bees are present. In the short term most activity can be ignored, but over time populations will increase and proliferate in the affected cement mortar, so proactive control in advance of this should be strongly considered.” – Bristol Pest Control