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Silverfish Control
Fast, wingless, teardrop-shaped and unnerving. They damage paper, books and fabric, and they’re telling you the same thing every moisture pest does.
Advertising disclosure: calls are routed to an independent local provider. We’re paid a referral fee for the call. You pay the provider, never us.
The short answer
Silverfish need high humidity — consistently above roughly 75% — and they die in dry air. They eat starches and cellulose, which means paper, book bindings, wallpaper paste, cardboard and natural fabrics. Insecticide kills the ones present; a dehumidifier removes the condition they need. In a persistently damp basement or bathroom, drying the space does more than any product.
They need
Humidity above ~75%
They eat
Paper, starch, cellulose
Real fix
Dehumidify
Also
Get boxes off the floor
Where they’re coming from
Four conditions, and all four are about water.
Most common
Bathroom and laundry humidity
The wettest rooms, and where they’re most often seen. Extractor fans running longer after showers changes it more than anything you can spray.
Common
Basement or crawl space damp
Persistent numbers in a lower level means the space itself never dries. That’s ventilation or drainage rather than pest control.
Overlooked
Cardboard stored on a concrete floor
Concrete wicks moisture, cardboard absorbs it, and the glue is food. A stack of boxes on a basement floor is habitat and a food source in one.
Structural
A leak behind a wall
Numbers concentrated in one area with no obvious damp usually means water inside the structure.
Why they damage what they damage
Silverfish digest cellulose and starch, which puts book bindings, wallpaper paste, photographs, cardboard and stored papers directly on the menu. They also graze on natural fibres — cotton, linen, silk — particularly where those have starch or food residue on them.
That’s why the damage shows up in stored boxes and rarely on things in daily use. Anything sitting undisturbed in a damp room is what gets eaten.
The dehumidifier point
They cannot complete their life cycle in dry air. A dehumidifier holding a basement below about 50% relative humidity ends a silverfish problem more reliably than any application, and it prevents mould and protects stored items at the same time.
It also costs less over a few years than repeated treatment, and it fixes a condition rather than a symptom.
Drying them out
Humidity first. Everything else is secondary.
Measure the humidity
A cheap hygrometer in each problem room. Above 70% is their territory; below 50% is not. This tells you where to act.
Run a dehumidifier
In basements and persistently damp rooms. The single most effective intervention, and it protects stored items too.
Extend bathroom ventilation
Fan running longer after showers, window open. Reduces the humidity spike they depend on.
Get cardboard off floors
Plastic boxes on shelving rather than cardboard on concrete. Removes both habitat and food.
Seal gaps and cracks
Skirting, around pipes, behind fitted units. They shelter in tight spaces during the day.
Use traps to monitor
Sticky traps in problem areas show whether numbers are falling as the humidity does.
What works
Where this stops being a DIY job
Damp you can’t locate. Numbers persisting after the humidity is controlled usually means water inside a wall or under a floor, which is leak detection rather than pest work.
A basement or crawl space that never dries. That has implications for timber, air quality and mould well beyond the insects.
Damage to stored documents or books already occurring. Conservation is its own field, and continued damp will keep causing it.
Advertising disclosure: calls are routed to an independent local provider. We’re paid a referral fee for the call. You pay the provider, never us.
What a competent visit addresses
Measures
Checks humidity
With a meter. A visit that doesn’t is treating symptoms.
Traces
Finds the water
Leaks, condensation, drainage. Not the insects.
Advises
Recommends a dehumidifier
Which competes with their own repeat business. Honest ones do it anyway.
Common questions
What causes silverfish?
High humidity, consistently above around 75%. They can’t complete their life cycle in dry air, which is why a dehumidifier ends the problem more reliably than any spray.
Do silverfish damage anything?
Yes — paper, book bindings, wallpaper paste, cardboard and natural fabrics, because they digest starch and cellulose. Damage shows up in stored items rather than things in daily use.
Are silverfish harmful to people?
No. They don’t bite, sting or carry disease. The damage is to stored materials.
How do I get rid of silverfish permanently?
Lower the humidity. A dehumidifier holding a room below about 50% relative humidity does more than repeated treatment, and it protects stored items too.
Damp inside a wall, or numbers that won’t drop?
A hygrometer, a dehumidifier and getting cardboard off the floor will end most silverfish problems permanently. Water inside a structure, or a crawl space that never dries, is where this needs someone with a meter.
Call (877) 360-4657