Cluster Fly Treatment for Lofts and Roof Spaces Across South Wales
Dozens of sluggish flies gathering at loft windows, around light fittings or on sunny walls every autumn are almost always cluster flies. They are not dirty and they do not breed indoors, but they come back to the same buildings year after year. Our NPTA-accredited technicians treat the roof space safely and close the gaps they use to get in.
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"Excellent professional service, resolved our problem completely. Highly recommended."
5.0 路 200+ reviews on Google & Checkatrade
"Excellent professional service, resolved our problem completely. Highly recommended."
Understanding the Problem
What You Need to Know About Cluster Fly Treatment
Cluster flies (Pollenia rudis) spend the summer outdoors, where their larvae live as parasites of earthworms in lawns and fields. In late summer and autumn the adults look for somewhere sheltered to hibernate, and lofts, roof voids, eaves and the upper rooms of houses are ideal. They are drawn to buildings that catch the sun, which is why the same south and west facing properties across Cardiff, the Vale of Glamorgan and the valleys see them every year.
They squeeze in through gaps around roof tiles, soffits, window frames and pipe entries, then pack into corners and voids in their hundreds, sometimes thousands. On warm winter days and again in spring they wake, head for the light and end up crawling over windows, loft hatches and ceilings in the rooms below. Homes on rural edges, or backing onto fields and parks, are hit hardest.
Cluster flies are not known to spread disease the way house flies do, and they do not lay eggs indoors. The problem is the sheer numbers, the dead flies that pile up and attract carpet beetles, and the fact that a building that suits them this year will suit them every year. Many lofts are also used by bats, which are protected by law, so the treatment has to be chosen with care.
Identification
Signs You Have Cluster Flies
- Large numbers of slow, sluggish flies at loft or upstairs windows in autumn or spring
- Flies clustered in corners of the loft, around the hatch, light fittings or roof timbers
- Dead flies building up on windowsills, in the loft and in light shades
- Flies appearing indoors on warm, sunny days in the middle of winter
- Flies slightly larger than a house fly, with golden hairs on the body and wings folded flat over the back
- The same problem returning to the same rooms every year
Not sure what you're dealing with? Visit our Pest Library or call us for a free phone assessment.
Why Act Now
The Risks of Leaving It Untreated
- Back Every YearCluster flies return to the same buildings year after year. Without treatment and proofing, the numbers tend to grow each season.
- Dead Fly Build-UpThousands of dead flies in a loft or wall void feed carpet beetles and other insects, creating a second problem in the home.
- Staining and NuisanceFlies crawling over windows, ceilings and light fittings leave small marks and make upstairs rooms unpleasant to use.
- Harm to Bats from DIY ProductsFly papers, sticky traps and the wrong sprays can kill bats roosting in the loft. All UK bats and their roosts are protected by law.
How We Treat It
Our Cluster Fly Treatment Process
A clear, step-by-step approach from initial survey to complete resolution, with no surprises and no hidden charges.
Loft and Property Survey
We confirm the species, find where the flies are gathering and check for any sign of bats before choosing a treatment.
Bat-Safe Treatment Plan
Where bats are present or suspected, we use targeted methods that will not harm them. Sticky traps are never used where bats may roost.
Targeted Treatment
Professional treatment is applied to the voids and surfaces where the flies cluster, timed for when they gather in autumn or wake in spring.
Clean Out
Dead flies are vacuumed from the loft, windowsills and light fittings so they do not go on to feed a carpet beetle problem.
Proofing and Prevention
We advise on sealing gaps around eaves, soffits, tiles and window frames, and can carry out the proofing for you.
Professional Treatment
Why Supermarket Fly Sprays Don't Solve Cluster Flies
Household fly sprays kill the flies you can see, but most of the cluster is hidden in roof voids, behind fascias and between tiles where a can will never reach. Within days the next wave walks out into the room, and next autumn the whole cycle starts again.
Professional treatment reaches the voids where the flies actually hibernate, and the survey tells you how they are getting in. Just as importantly, a trained technician checks for bats before anything is used. Getting that wrong is not only harmful to a protected species, it can be an offence.
- Treatment reaches the roof voids where the flies hibernate
- Bat checks before any product is used
- Targeted methods, with no sticky traps near roosts
- Dead flies cleared so they don't attract carpet beetles
- Proofing advice to cut numbers next season
Prevention First
How to Prevent Cluster Flies
Professional treatment resolves the problem. Prevention stops it coming back. Our technicians will always advise on the specific steps most relevant to your property.
Seal gaps before late summer
Fill gaps around soffits, fascias, roof tiles, pipe entries and window frames before the flies start looking for winter shelter in late summer.
Fit fine mesh to loft vents
Mesh over vents keeps flies out without blocking the airflow your roof needs. Only fit it where bats do not use the opening.
Clear dead flies every spring
Vacuum dead flies from the loft and windowsills each spring so they don't feed carpet beetles.
Book treatment early
Treating in early autumn, as the flies arrive, works better than waiting until they are already packed into the roof.
FAQs
Cluster Fly Treatment, Frequently Asked Questions
Got a question we haven't answered?
Call our team for a free, no-obligation phone consultation.
02922 404605What Our Customers Say
Trusted by Hundreds of South Wales Customers
"Excellent service from start to finish. Resolved our problem completely and quickly. Very professional."
"Needed cluster fly treatment urgently. They attended same day and sorted everything properly. Brilliant service."
"Very knowledgeable, friendly team. Explained everything clearly and followed up to make sure the problem was fully resolved."
Need Cluster Fly Treatment in South Wales?
Same-day response available. No call-out charge. Treatments backed by a written guarantee.
Cluster Fly Treatment Service Areas
We cover all of South Wales, call us to confirm coverage for your area.