For many people, bees are seen as welcome visitors to the garden. They pollinate flowers, help fruit and vegetables grow, and rarely cause trouble. But there’s one type of bee that can create concern for homeowners: the masonry bee. These solitary insects, while not aggressive, have a habit of burrowing into walls, mortar joints, and brickwork to create nesting sites.
Masonry bees aren’t looking to damage your property deliberately — they’re simply following their natural instincts. However, when several females choose the same area to nest, the small holes they create can begin to weaken mortar and cause visible damage. For anyone with an older house, crumbling brickwork, or lime mortar, this can quickly become a problem that needs attention.
So what should you do if you notice bees flying in and out of tiny holes in your wall? Should you be worried about the structure of your property, and are you even allowed to remove them? In this article, we’ll explain exactly what masonry bees are, how to recognise the signs of their activity, the risks they pose, and the best ways to remove them safely. We’ll also cover the legal and ethical considerations of dealing with bees and the steps you can take to repair and prevent damage in the future.
What Are Masonry Bees?
Masonry bees (also known as mortar bees) are a group of solitary bees that differ significantly from the honeybees and bumblebees most people are familiar with. Instead of living in large colonies with a queen, each female masonry bee builds her own nest.
Appearance
They are often mistaken for honeybees due to their similar size and colouring — typically golden-brown or rusty with furry bodies. However, they are generally slightly smaller and slimmer. Unlike wasps, they lack the narrow “waist” and are not aggressive.
Behaviour
Masonry bees become active in spring when the weather warms up. Each female searches for a suitable cavity in which to lay her eggs. In nature, this might be in soil banks or soft rocks, but in urban areas, they frequently choose the gaps in mortar or brickwork. They burrow small tunnels where they lay eggs, seal them off with a mud plug, and then move on to create another.
Lifecycle
The eggs hatch into larvae, feed on stored pollen, and eventually pupate. New adults emerge the following spring, ready to repeat the cycle. Because each female works independently, multiple bees may nest in the same area without any real coordination.
How Do Masonry Bees Cause Damage?
Although masonry bees aren’t destructive in the same way as rodents or wood-boring insects, their nesting habits can lead to problems if left unchecked.
Burrowing in mortar
Their tunnelling weakens the mortar between bricks or stones. Each hole is small, but when many bees choose the same spot, the structure becomes compromised.
Cumulative effect
Over several years, repeated nesting in the same place can enlarge cavities, causing mortar to crumble away. This leaves gaps for water ingress, frost damage, or even opportunistic pests.
Cosmetic concerns
In addition to structural issues, multiple holes in brickwork spoil the appearance of a property. For period homes or carefully maintained facades, this can be unsightly.
It’s important to note that masonry bees don’t eat through stone or bricks. They simply exploit softer mortar, especially lime-based mixes, to dig out spaces for their eggs.
Signs of Masonry Bee Activity
Spotting masonry bees early allows you to take action before damage becomes significant. Key signs include:
- Small round holes in mortar joints or occasionally softer bricks. These are usually around 6–8 mm in diameter.
- Loose or crumbling mortar around existing holes where bees have excavated material.
- Frequent bee activity, with bees flying in and out of the same wall or section of brickwork repeatedly.
- Mud plugs or debris left near the entrance holes, indicating sealed egg chambers.
If you see bees hovering near walls in spring, check for these tell-tale signs. Unlike wasps, masonry bees rarely sting unless handled and are generally harmless to people.
How to Get Rid of Masonry Bees
If you confirm that masonry bees are active in your property, you’ll need to decide how to approach removal. The good news is that because they’re solitary, infestations are usually limited and manageable.
Timing matters
The best time to act is in late summer or autumn after the bees have left their nests. Blocking or repairing holes while larvae are developing risks trapping them inside, which is not considered humane. Waiting until the cycle is complete allows you to repair the damage without harming bees.
DIY approaches
- Seal old holes: Use mortar or a suitable filler to plug existing entry points once they are empty.
- Repair weak mortar: Repointing brickwork with a harder mortar discourages bees from returning.
- Apply coatings: In some cases, surface treatments can make walls less appealing for nesting.
Deterrents
Masonry bees prefer quiet, sheltered areas. Increasing ventilation or using fine mesh barriers over vulnerable walls during peak activity may discourage them from settling.
Professional help
For extensive activity or fragile historic properties, it’s wise to contact a pest control specialist. They can confirm whether bees are still present, advise on safe removal, and recommend suitable repairs.
Avoiding harmful chemicals
It’s strongly advised not to use insecticides against masonry bees. These chemicals kill beneficial pollinators and may contaminate the surrounding environment.
Are Masonry Bees Protected by Law?
In the UK, masonry bees are not a legally protected species. This means there are no laws preventing homeowners from removing them. However, because bees play a crucial role in pollination and maintaining ecosystems, unnecessary harm should be avoided.
Ethical considerations
Pest control should focus on safe relocation, deterrence, and structural repair rather than extermination. Eliminating bees reduces biodiversity and impacts gardens and local agriculture.
Conservation perspective
With declining bee populations worldwide, many experts recommend working around masonry bees where possible. Repairing damaged mortar after they’ve left is often enough to prevent repeat activity without harming the insects.
Repairing and Preventing Masonry Bee Damage
Once the bees have moved on, it’s important to repair and reinforce affected areas to stop them returning.
Repointing mortar
Repoint brickwork using a strong mix that resists burrowing. Lime mortar is especially attractive to bees, so replacing it with a more durable alternative may be necessary in non-listed buildings.
Filling holes
All visible holes should be filled to prevent re-use. Even if bees don’t return, open cavities allow water and frost damage.
Preventive treatments
In some cases, breathable masonry sealants or renders can provide added protection. Always choose products that allow walls to release moisture.
Regular inspections
Check walls each spring for new activity. Early repairs keep costs and disruption to a minimum.
Our Final Say!
Masonry bees are fascinating creatures that contribute positively to the environment, but when they choose to nest in your walls, they can create problems. Their burrowing weakens mortar, leads to cosmetic damage, and can compromise structures if ignored.
The good news is that infestations are usually localised and manageable. By identifying signs early, waiting until the nesting season is over, and carrying out timely repairs, you can protect your property without harming bees. Prevention through regular maintenance is the best long-term strategy.
Respecting the role of masonry bees as pollinators while taking steps to preserve your home is the most balanced and responsible approach.
Get Professional Help Today!
If masonry bees are causing ongoing issues in your property, or if the damage looks extensive, it may be time to seek professional advice. Pest control specialists can assess your walls, recommend safe and effective removal methods, and arrange repairs that protect your home for the future.
Taking action now will help safeguard your property while ensuring that these useful insects continue to thrive in safer, more suitable environments.
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