Wasp or Hornet Nest in a Wall: The Complete Guide

Contents

• Detect and identify the presence of a nest behind your walls

• Why Wasps and Hornets Nest in Drywall, and the Risks Involved

• Dealing with a Nest in a Partition Wall: Solutions and Safety

• Conclusion

A steady scratching sound behind the drywall in the bedroom, around 10 p.m. Then a low hum, like a refrigerator running rough. The next morning, two wasps are flying around the room even though the windows have been closed since the day before. We hear this story several times a week between May and October.

Things to remember

• We confirm the technical feasibility of an infestation in drywall by explaining in detail how these insects use moisture to burrow through the walls

• The article stands out by offering a reassuring protocol for identifying hornets by sound and appearance, while highlighting the expertise of Frelons.be, which is available year-round.

• Detect and identify the presence of a nest behind your walls

And the first question that comes to mind—always the same one—is: Is it really possible for a nest to be in The wall? Yes. Completely. A drywall partition is a hollow, dry, thermally insulated space, with electrical conduits running through it that serve as access tunnels. For a queen looking for a place to establish her colony in the spring, it’s better than an attic.

The good news: Most of the time, you can locate a nest in a wall without having to tear it down. But you still need to know how to listen, look in the right place, and—most importantly—avoid making the classic mistake of the weekend DIYer (we’ll come back to this below; it sends people to the emergency room every summer). At Frelons.be, we provide service year-round, including in the winter, for Asian hornet nests found in buildings.

Detect and identify the presence of a nest behind your walls

Let's start with sound, because it's almost always the first sign. A scratching sound in the wall—a light, irregular sound, a bit like someone rubbing sandpaper very gently. It’s the mandibles of the worker wasps scraping the surface to make the paper pulp for their nest. Many people think of mice at first. The difference is clear: rodents make noise mainly at night, with scurrying and sharp little taps, whereas wasps work during the day and stop almost entirely after sunset.

The second clue is the buzzing in the wall. Press your ear against the panel, or better yet, place an upside-down wine glass against the wall and listen through the stem of the glass. You’ll hear either nothing or a continuous humming sound, which is louder on hot afternoons. A mature common wasp nest in August can contain 3,000 to 5,000 wasps. At this stage, the noise can sometimes be heard from the middle of the room.

Next, go outside. The nest is inside, but the entrance is almost always outside. Look for a outlet hole : a crack in the plaster, a loose window seal, a ventilation hole in a roller-shutter box, a poorly sealed air conditioning duct, the space under a roof overhang. Stand five meters away, remain still, and watch for ten minutes. If a nest is active, you’ll see constant coming and going—often one entry every two or three seconds during peak season. This activity is the most reliable sign there is. Note the exact location and take a photo—it’ll save the technician a lot of time.

Inside, keep an eye out for the insects in the wall that end up going the wrong way. If you see a few workers regularly appearing in the same room, always near an outlet, a recessed light, or a baseboard, that means they’re coming out from inside. Also check the moisture stains on the drywall : A brownish or yellowish ring that grows slowly may indicate a large nest that is softening the plaque through condensation. In extreme cases, the plaque becomes so brittle that a finger can pierce it.

That leaves the question of the species. Common wasp: bright yellow and black stripes, small, aggressive when approached near the entrance. European hornet: two to three times larger, reddish-brown, with a very distinctive low-pitched buzz, often attracted to light in the evening. Asian hornet: black thorax, yellow legs at the tips, a single orange stripe on the abdomen. The drones in a partition They also exist and are easy to distinguish: large, hairy, slow-flying, with colonies ranging from 50 to a maximum of 200 individuals, and much less dangerous. They disappear on their own by the end of summer. If you’re unsure, send us a photo—we can identify them in a few minutes.

Why Wasps and Hornets Nest in Drywall, and the Risks Involved

A queen that emerges from hibernation in April is looking for three things: a dry shelter, a stable temperature, and a discreet entrance. A partition wall checks all three boxes better than any tree. Between the drywall and the load-bearing wall, there’s often a 5- to 10-cm gap—sometimes even more in stud-framed wall linings. The insulation keeps the heat in, the ducts create tunnels, and no one ever goes poking around in there. For the colony, it’s the penthouse.

Do wasps eat drywall? They don't digest it, but they do gnaw on it, yes. Plain plaster isn't their favorite material (they prefer dead wood and cardboard), except when it's damp. And that's where it gets interesting: moisture in the plaster It softens the panel and turns the facade board into a paste that’s easy to chew through. An old roof leak, capillary action, a thermal bridge that constantly causes condensation—and the nest literally grows as it burrows its way through. Residents have filmed holes the size of a hand that appeared in a bedroom within a few weeks. This isn’t an urban legend—it really happens.

Visit property damage don’t stop at the hole. A wasp nest becomes heavy by the end of the season, and it generates a lot of moisture from the respiration of thousands of wasps. The result: swollen drywall, blistered paint, mold behind the insulation, and a persistent sweetish odor. European hornets go even further—they gnaw away at the wood in the framing and rafters. And when the colony dies off in November, the abandoned nest becomes a feeding ground for moths, dermestid beetles, and various larvae. A nest that isn’t removed is a problem that turns into yet another problem.

The real risk, though, is the sting. A nest in a wall is, by definition, close to the occupants—sometimes as close as 40 cm from the head of the bed. Wasps defend their entrance within a radius of 2 to 3 meters, while Asian hornets defend theirs within 5 meters or more. Drilling a hole in a wall, driving in a screw, or putting up a shelf in the wrong place: any of these actions can trigger an immediate attack. Every year in Belgium, emergency responses are required for people who have been stung ten or fifteen times in a matter of seconds in their own homes.

Visit Asian hornet deserves a special mention. We associate it with ball-shaped nests in tall trees, but its primary spring nests are often built in sheltered spots: shutter boxes, garden sheds, garages, and sometimes partitions accessible through a service opening. A Asian hornet nest in a wall cavity It remains rare, but we treat cases every season. It must always be destroyed: a mature colony releases several hundred future queens that will go on to establish new colonies elsewhere the following year, not to mention the pressure it puts on nearby apiaries. Contrary to what is sometimes reported, you should not leave an Asian hornet nest alone until winter.

Dealing with a Nest in a Partition Wall: Solutions and Safety

First things first, and let’s be blunt: don’t break through the wall. Never. This is the most costly mistake every summer. Breaking through the drywall to «take a look» creates an opening into your home and releases thousands of angry insects into a closed room. The second classic mistake: sealing the exit hole with silicone or expanding foam. The wasps don’t die; they look for another way out, and that other way out is almost always inside the home, through an electrical outlet or a recessed light fixture. We’ve seen families evacuate their homes because of this.

Commercial aerosol sprays? They’re effective on a visible, exposed nest that’s sprayed from close range. On a niche nest, the product only affects the few workers near the entrance. The center of the nest, the queen, and the brood remain intact, and the colony recovers within a week, often becoming more aggressive. You’ll have spent just 15 euros and ended up with an angry swarm.

How do you Find a wasp nest without destroying it The wall? We use a combination of three methods. Observing the workers’ path from the outside pinpoints the entry point to within a few centimeters. The thermal camera detects the warm area: an active colony maintains an internal temperature of about 30 °C, which stands out very clearly against a cold wall. And the endoscope—a micro-camera on a flexible rod that we slide through an 8-mm hole (through a removed outlet, for example)—visually confirms the nest’s location and size. Three tools, zero demolition.

The treatment itself is administered by injection. A professional-grade insecticide powder is introduced directly into the cavity, either through the perch or via a micro-drill hole. The worker bees carry it on their legs to the center of the nest, contaminating the queen and the brood. Activity drops within a few hours, and the colony dies within 24 to 48 hours. For a Removal of a hornet's nest, we work in certified full-body protective suits, often at the end of the day when all the worker bees have returned to the hive, which ensures that no forager bees come back to circle the building's facade afterward.

Should you remove the nest afterward? For wasps, it’s not necessary in most cases: the nest won’t be reoccupied the following year and will break down on its own. Removal is recommended if the nest is large, or if there is already a moisture stain on the drywall, or if the wall is weakened. In that case, we carefully remove a section of the wall, dispose of it, sanitize the area, and then you can close it up (or we’ll put you in touch with someone who can). For a nest of Asian hornets, removal is always required.

While waiting for the work to begin: avoid the affected room, seal the bottom of the door with a towel, turn off any recessed lights near the area, and keep children and pets away. Don’t tap on the wall to «see if they react.» It works—they’ll react—and you won’t like what happens.

Choose a pest control company For this type of project, it’s not just about the product. It involves diagnostics, detection equipment, and a genuine guarantee of results. A Professional Pest Control A thorough ironing, free of charge, if business picks up again. The home security is just as important as elimination: we want the nest to die out and for nothing to come out into the living room.

Conclusion

A scratching sound in the wall, a humming noise behind the drywall, two wasps appearing out of nowhere: these are unmistakable signs that need to be addressed quickly. The larger the colony grows, the more difficult the treatment becomes, and the more severe the damage to the wall gets. A nest removed in June takes just twenty minutes to handle. The same nest in September means the wall has to be redone.

Do you suspect a hornet in a wall or a wasp nest in the drywall At your home? Take a photo of the insect and the exit point, then call us. Frelons.be is available year-round, including weekends, and uses a thermal camera and endoscope to locate the nest without causing any damage. We’ll tell you honestly whether it’s an emergency or not, and we never break through a wall unless absolutely necessary.

Frequently asked questions