One challenge with carpenter ants is that they often go unnoticed. They prefer damp or decaying wood, meaning you may not realize there's a problem until the infestation is well-established. That’s why knowing where to look and acting fast can help prevent costly repairs.
Piles of sawdust-like frass
Carpenter ants produce frass, which looks like sawdust. It’s made of wood shavings, insect parts, and debris they remove from tunnels. Unlike termites, which digest wood, carpenter ants discard it.
Frass often builds up near baseboards, under wooden furniture, or in crawl spaces. If you find small piles of powdery debris indoors, and there’s no clear source, it could mean an infestation. Sometimes, frass may also contain parts of dead ants, which is another clue that an active ant colony is nearby.
To locate the source of frass, check along walls, inside cabinets, and around wooden beams. If you see piles of frass near small openings around your home, you might have multiple carpenter ant colonies.
If frass continues to appear even after cleaning, it’s a sign that the ants are still actively tunneling. This means they are constantly working to expand their nest, potentially weakening the structure of your home.
Hollow-sounding or damaged wood
Carpenter ants carve smooth tunnels inside wood. Over time, this can weaken structures, making them sound hollow when tapped. If walls, door frames, or furniture break easily or feel soft, there may be a colony inside.
Unlike termite damage, which is rough and packed with mud, carpenter ant tunnels are clean and polished. Use a screwdriver to check suspected wood—if it crumbles or feels hollow, ants may be nesting inside. The longer an infestation goes untreated, the more widespread the damage will become.
If you notice sagging or warped wooden structures, it could be a sign that carpenter ants have been tunneling inside for an extended period. Replace damaged wood right away, and contact a pest control expert to help prevent future problems.
Large, black ants inside or around your home
Carpenter ants are some of the biggest household ants, measuring 1/4 to 1/2 inch long. Most are black, but some have reddish-brown coloring. Unlike most common smallerants, they prefer damp wood over food crumbs.
If you frequently see large ants, especially in kitchens, basements, or near windows, you may have a growing infestation. Even if you only see a few ants at first, it’s important to monitor their activity. Carpenter ants often have well-hidden nests, and spotting workers indoors could mean a larger colony is nearby.
During warmer months, carpenter ants may be seen traveling in and out of your home.If you see a line of ants on walls, baseboards, or tree branches, they are probably going from their nest inside to find food outside.
Rustling sounds within walls
Carpenter ants are most active at night. As they tunnel, they can create a faint rustling or scratching sound. These noises are usually heard in quiet areas, especially near baseboards and window frames.
If you hear these sounds along with other warning signs, it may mean ants are inside your walls. Rustling noises usually mean ants are busy building a network of tunnels in your home.
In severe infestations, these sounds may become louder, especially when the colony is disturbed. If you suspect an infestation, listen carefully at night when carpenter ants are most active.
Discarded wings near windows and doors
During mating season, reproductive carpenter ants (swarmers) leave the nest to start new colonies. After mating, they shed their wings. You may find these small, translucent wings on windowsills, near doors, or around vents.
Unlike termite wings, carpenter ant wings are longer in the front than in the back. If you find wings indoors, check for other signs of infestation. Seeing swarmers indoors is a red flag and can suggest that a nest is already established within your home.
Finding discarded wings near window sills or on countertops is often one of the first visible signs of an infestation. Since swarmers are responsible for reproduction, their presence can indicate that the colony is growing and could soon expand to other parts of the home.