Is sawdust in your home a sign of insects?

For many homeowners, the sight of sawdust piles in their homes can cause a lot of anxiety and bring up fears of detrimental termite damage. However, termites are not the only pest that leaves sawdust-like piles behind. For Canadians, the major culprits are termites, carpenter ants, carpenter bees and powder post beetles. To properly treat an infestation, it’s important to correctly identify the pest. This article equips you with all the necessary information to understand your problem and choose the right treatment option for your home.

Construction Sawdust

Take a deep breath. Before jumping into the various pests that can leave sawdust behind, take a second to remember if you’ve had any minor construction done lately. Perhaps a photo was hung on the wall, a new cabinet was installed or a plumber or electrician recently completed repairs that involved them drilling through your home’s wood joist or stud framing. Alternatively, if you recently moved into your home, check with the previous owner or a neighbour to find out if construction work was carried out prior to your arrival. If one of these explanations lines up with the location of the sawdust, simply vacuum it up and carry on.


Termites are infamous for their destructive abilities and for good reason, they cause the most damage out of all the wood-infesting insects. Historically, they were confined to warmer climates, but since the mid-twentieth century; they have expanded their ecological range, moving from the southern US to the north and into parts of southern Canada, Toronto especially has a termite problem. There are three main types of termites that cause problems for homeowners: subterranean, dry wood and wet wood, but it is only the dry-wood termites that leave behind these sawdust-looking piles.

The “sawdust” left behind by dry-wood termites is actually not sawdust at all but their feces, called frass, it looks similar to wood because that’s all termites eat. However, the debris is in uniform pellet shapes instead of irregularly shaped wood shavings and the piles of waste they leave behind are rather small, as much of the wood is being digested and consumed. Look for small, pinhead-sized holes near the frass.

Termites live in large colonies made up of thousands of termites but are not often seen as they stay living deep in the wood. However, you may see some flying termites leave the nest to mate and create new colonies during the summer or fall.

Carpenter Ants

Carpenter ants exist all throughout Canada but thrive in more humid regions. In the wild, they help in the decomposition process of dead trees. However, they are also attracted to damp or decaying wood in your home.

Unlike termites, carpenter ants leave true sawdust piles as they don’t eat wood. Instead, they create tunnels towards a centralized nest where they live and lay their eggs. They like to keep their tunnels and nest very clean and consistently sweep all the sawdust and other debris out, creating conspicuous piles. Look for their slit-shaped holes near sawdust piles as well as the bodies of small insects in the debris, as carpenter ants feed on other insects.

Carpenter ants live in large colonies with hundreds of individuals, and foragers will search around the house for protein or sugar-rich foods to bring back to the nest. Out of all the wood-infesting insects, they are the ones you would most likely see. Keep an eye out near sawdust piles, in the kitchen and in moist areas like by the windows. Carpenter ants are rather large and dark brown or black in colour and they are most active after sunset. Additionally, both males and females can grow wings during mating periods and you may see them flying around the house.

Carpenter Bees

Carpenter bees create burrows in exposed wood that they use as nests, leaving behind the excavated sawdust. The entry holes to their burrows are larger than that of the other insects on this list, about the size of your fingertip and almost perfectly round. This is the easiest way to identify carpenter bees, as they are solitary animals and don’t live in large groups. They look very similar to honey bees but with shiny black bodies instead of fuzzy yellow and black bodies. Although they don’t live in colonies, the next generation of bees will build their own nests nearby, causing increased damage over time. Be especially careful when investigating, as they can sting. 

Powder-Post Beetles

Powderpost beetle is a general term for a group of small beetles that turn wood into a powder. The “sawdust” varies in appearance based on species but is generally finer than that of other wood-infesting insects. The “sawdust” left by powderpost beetles is again not true sawdust but frass, while the larvae are growing in the wood they consume and digest it creating the powder, when they become adults they tunnel out of the wood pulling the dust along with them and creating small piles. 

It is unusual to see the beetles themselves, but they can be identified by their distinctive hole pattern. Each beetle tunnels out on its own, leaving a collection of small holes in close proximity to each other. 

Wood infested by powderpost beetles can be abandoned after they all mature and bore out. This requires no treatment. However, the dust can stay in the holes for years after the beetles have left getting knocked out by movement, such as walking or jumping on the floorboards. So it is always good to get an inspection done to make sure the wood is truly abandoned. The dust produced by an active infestation will be similar to the colour of wood, but over time will oxidize and take on a rusty colour. 

The moisture content of wood is paramount for an active beetle infestation so they are most common in dirt floor basements and sheds. 

Other Sawdust Sources

Although not often in large quantities, sawdust can also be generated by your home naturally settling. The wood framing rubs together at joints, creating small amounts of dust. Even wooden furniture can create dust as it is used and the joints rub together. 

However, if you have cleaned up sawdust piles but they keep appearing, it is likely that you have an infestation of one of these insects. Wood infesting insects can lead to major structural issues over time, so you want to act quickly and call a reputable pest control company to properly diagnose and treat the problem.

Terminix Canada offers expert pest control services across Canada including BC, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia and Newfoundland. Call us today to learn how we can help.