Carpenter ants are the largest ant species in Chicago and can cause real structural damage. Unlike termites they don't eat wood — they excavate it to build smooth nest galleries, typically targeting wood softened by moisture from leaky roofs, decks, or basement walls.
What Do Carpenter Ants Look Like?
Carpenter ant workers are large — 1/4 to 1/2 inch long — and usually solid black, though some species are reddish-brown. They have a single node between thorax and abdomen and a smooth, rounded back when viewed from the side. Winged reproductives appear in spring.
Where Do Carpenter Ants Hide?
Carpenter ants nest in moisture-damaged wood. In Chicago that means around leaky window frames, behind dishwashers, around bathroom plumbing, in soffits and fascia boards, in basement sills near grade, and inside hollow porch posts and deck boards. Satellite colonies often appear inside walls far from the parent nest.
Signs of a Carpenter Ant Infestation
Look for large black ants indoors year-round (not just summer), small piles of sawdust-like 'frass' below baseboards or windowsills, faint rustling sounds inside walls at night, and winged swarmers near windows in spring.
Health Risks of Carpenter Ants
Carpenter ants don't transmit disease and only bite if directly handled. The real risk is structural — left untreated, colonies can weaken framing members, sills, and door frames over a period of years.
How Sleep Tight Treats Carpenter Ants in Chicago
Sleep Tight finds the parent nest using non-repellent treatments and targeted dust into wall voids, treats satellite colonies, and identifies the moisture source feeding the infestation so it doesn't return. Repellent over-the-counter sprays scatter the colony and make the problem worse.
Need help with carpenter ants in Chicago?
Sleep Tight Pest Control offers same-day chicago ant control across every Chicago neighborhood and suburb. Call (773) 240-5932 or get a free quote online.
Frequently Asked Questions
Are carpenter ants as bad as termites?
They cause less damage per year than termites, but a mature carpenter ant colony left untreated for several years can still cause expensive structural repairs.
Why do I see them inside in winter?
Seeing carpenter ants indoors in winter is a strong sign there's an active nest inside your home — they're not coming in from outside in cold months.
Do I need to replace the damaged wood?
Often the wood is still structurally sound — but the underlying moisture problem must be fixed or the ants will return after treatment.
How long does treatment take?
Most Sleep Tight carpenter ant jobs show major activity reduction in 7–14 days, with full colony elimination in 4–6 weeks.