Expelling Bees in flat roof

AnthonyL snipped-for-privacy@please.invalid wrote

I had the same problem but noticed it with the bees flying in and out of where they were getting into the flat roof.

Just hit the buggers with fly spray for a week or so and eventually they got sick of it and chose to bugger off

I had them in my roof void too, a couple of years ago. I've heard it said that the queens which have overwintered don't return to the same place every year but presumably what makes it attractive to the hive of '22 will make it attractive to the hive of '23 and when I discovered the problem, bees had clearly been coming and going for far more than one year. Honey and fibreglass insulation - yuk!

There are, I believe, several things that the bees find repellant including lavender - but how could I be sure that a spray wasn't just some chemist's interpretation of lavender and would actually work?

In the end I plumped for garlic - as little wanna-bee (sorry!) vampires, they can't stand the smell of garlic so I sprinkled garlic powder around the loft and especially near the places they'd been coming in and out. (I could see them flying in and out of those places from the ground.) Anyway, I've renewed the garlic powder each year and I haven't seen them in the loft since but I'm pleased to say they still keep busy in the garden.

Hope this helps.

Nick

It may be late in the season for mason/masonry bees.

Are you sure that they are not wasps? In some areas they have been a major problem this year. Two friends of mine on the Welsh boarders have had 8 nests between them this year on the eves and in the loft. All nests destroyed early Summer. One friend made a mistake calling out one of the large National pest extermination companies and had a bill of over £250 to destroy 2 nests. The local pest control man, and his dog, charged £60 for as many nests found on the same visit.

If it's wasps the new queen will be looking for somewhere to hibernate and the old queen and other wasps will die off each year as the weather gets colder. Wasp nests are not re-occupied. Wasps get a bit arsey this time of year especially if queen is not around so be careful with dealing with them.

Vinegar doesn't discourage wasps or hornets. A popular trap for wasps is a jar with some jam and vinegar. The latter ingredient discourages honey bees so they don't get trapped. The container also needs a small hole for an entrance but stops the wasps flying back out.

alan_m snipped-for-privacy@admac.myzen.co.uk> wrote

Wasps dont leak stuff thru the ceiling and at least ours don't nest inside a flat roof, the build their things outside, on both vertical walls and the eaves underside

Wouldn't suggest this for friendly bees but I effectively got rid of an active inaccessible wasps nest behind an air brick earlier this year, by a regular dusting of ant powder where they were flying in, the cheapest thing ye can get. A Turkey Baster would be able to puff more of that Permethrin laced product into a hole. You have to keep reapplying, and use new product - some I bought years back was ineffective, didn't cause them paralysis.

Noted that there is now a major industry in B&Q selling every variant of wasp killer they can manufacture, at ten times the price.

Ant killer. Talcum for Ants. e.g.

How urgent is it? They aren't nesting at this time of year.

AIUI if they're actually bees not wasps then they will die off over winter and if honeybees the queen won't return to the same site. So all you need to do is wait for them to leave and then block up any holes that allow them to enter. Then your site is less attractive to next year's cohort.

Theo

Honey bees don't fully desert their home nor do they all die off during winter. A (new) queen will leave the hive with a proportion (maybe thousands) of worker/foraging bees. This is when they are swarming and usually resting frequently in large clumps. The queen is not a good flyer and needs to frequently rest, being protected by the rest of the bees by surrounding her. These swarms are relatively safe and there is no need to move them on or destroy them. They will move on at the own accord, usually within hours or occasionally a day. (Assuming you cannot get a bee keeper to collect them to populate a new hive) When swarming worker bees will be looking for a new home and the swarm will ultimately move in when a new home is found. This is unlikely to happen this time of year because for a new colony to survive they must have collected enough food to see them over winter (honey).

The bees and queen left behind will continue. They will have built up a stock of food (honey) during the warmer months so they don't have to forage during the colder months. They will become visibly active again as the weather warms up next year. A hive can die off if it gets too cold and that's why bee keepers install insulated jackets to the hives during winter.

A queen bee lifespan is around 4 years. A worker bee's lifespan in summer maybe 1 month and up to 6+ months in colder winter conditions.

I'm not sure and as the entrance is on my neighbour's side. I've just been on the flat roof (7.15pm) and they are coming in. Had to lie down and look under the gutter and there the problem is, the air vent for the cold flat roof has lost its insect gauze. I've put a wasp trap in the gutter and will see what is there in the morning though of course that will not be definitive. I've got a net so I might be able to catch a couple and try and id.

There is an air vent on the opposite (my side) of the extension so I could have a look in there with a torch tomorrow.

The signs are fairly recent and I posted a separate thread when I thought it might be a water leak:

"Subject: Plasterboard above shower discolouring - help Date: Fri, 29 Aug 2025 08:14:30 GMT"

SWMBO thinks the first signs were after mid-August though it could have taken a few weeks to come through and be noticed. Not sure what is the mechanism for the discolouration.

A bit of behaviour from the other day:

All the occupants got fairly agitated.

I've revised my entomology and having captured and photographed one they would seem to be Common Wasps:

So what's my best option now, bearing in mind that they may well be munching away at my flat roof joists? I'm not really into unecessary killing off wildlife. Wait till spring and close all openings up then or deal with them now?

I can only readily get to the entrances and not to any nests themselves.

Or do I need to get a man in?

I would simply close up openings now. They will die anyway then.

This is where a 3D printer to print new insect meshes is a handy tool.

Depends on whether you are up to fitting new eaves vents with insect proofing

Or buy it ready made for far less than the cost of a 3D printer.

Do nothing. They will all have died off in a few weeks, the queen will find somewhere to hibernate over the winter and will start a new nest elsewhere in the spring.

Over the winter, block off their entrance hole(s) to stop another colony setting up home there, either with some fine mesh or solid filler.

It's like car body filler,. It's an investment Ive made so many little angle brackets, fishplates, odd shaped plasticky things to replace lost of broken plasticky things, and cases for electronics projects, that you wouldn't believe.

Bought some Raaco cabinets. no dividers, Printed off a hundred ...

I'm confused as to why they are building a nest now; isn't that for the queen?

It's a (now broken) ventilation grid for the cold roof. Not a problem to replace presuming I'm not attacked in the process.

They are not necessarily 'building' a nest, merely occupying the nest they've built over the spring and summer, raising a few grubs etc. and bringing in food for those grubs. Actual nest building activity will be much reduced. As autumn turns to winter and the weather cools, the wasps will all die off, and young queens will fly away to find places to hibernate over the winter, to start new nests elsewhere in the Spring.

You are worrying unnecessarily!

Read about wasps and their life cycle here

Wait until all activity has ceased, probably in November or leave it even later.

At this time of year if they are not bothering you just leave them alone and they will die off over the next month, only get a man in if they become aggressive and are attacking you. As far as chewing away at your joists again I should not worry. At our last house we had timber reveals around our windows and the buggers got into the cavity through a small hole under the lintel. Because it was my daughters bedroom and I was worried they would get into it I got a man in. However some time later we had UPVC windows fitted and the wooden reveals were removed, the nest was quite considerable and they had chewed at the reveals to construct it but they were no where near eating their way through the 20mm wood.

Wasps will not re-occupy an old nest. One method to keep new nests out of your garden is to put false nests about apparently they are territorial and actively avoid other colonies. How well that works I have no idea.

Richard

Perhaps not, but they will build one very close to an old one. My house has had a wasp's nest in the roof most years for the last

-- Richard

Very interesting.

Yes, got it (eventually) now thank you.

I'm glad they are not going to cause the ceiling to collapse though the plasterboard is now quite discoloured and damp with their activity and I suspect that SWMBO will at least require a section to be replaced.

When I fix the broken vent I'll try and rake what's left in there out once it's clear all activity has ceased.

As Richard Tobin has said, if there is a way into the flat roof void I'm sure some enterprising queen wasp will find the accommodation attractive and there are plenty of plants/flowers/bushes nearby including one belonging to the neighbour that is against the side of the extension that is providing access.