Small piles of what looks like sawdust below a beam, a windowsill, an eave, or a deck rail come from one of four sources — and in Virginia the most common is one people rarely suspect: carpenter bees. The other candidates are carpenter ants, drywood termites, and ordinary construction debris. The material itself tells you which, and so does whether the pile comes back.
This is general information. Identification from a description is never certain. Keep a sample and have a licensed inspector look at it.
The single most useful test
Sweep it up and wait two days.
Construction debris does not return. Drilled or cut wood from recent work leaves sawdust once; clear it and nothing reappears within two to three weeks.
Insects keep pushing. Carpenter bees continue excavating, carpenter ants continue clearing galleries, and drywood termites keep ejecting pellets through the same kick-out holes. The pile reappears in the same place, often within a day or two.
Many homeowners sweep up the same small pile for months before realising it is not going away on its own.
Four sources, and how they differ
| Source | The material | Where you find it | The hole |
|---|---|---|---|
| Carpenter bees | coarse sawdust, often with yellowish staining below | eaves, fascia, deck rails, trim, exposed exterior wood | round, smooth, about 3/8 inch |
| Carpenter ants | coarse shavings mixed with insect parts and soil | windowsills, near damp or damaged wood | irregular slit-like openings |
| Drywood termites | dry, six-sided pellets — looks like sand or coffee grounds | below infested wood, indoors | tiny kick-out holes |
| Construction debris | uniform sawdust, no insect parts | wherever work was done | none |
The clearest single distinction: carpenter bee holes are round, smooth, and remarkably neat, as if drilled. Nothing else makes a hole that looks manufactured.
The second clearest: drywood termite frass is pellets, not dust. Under any magnification the particles are hard, dry, and six-sided rather than fibrous.
Carpenter bees: the Virginia default
Virginia has the eastern carpenter bee, and it is by far the most common explanation for sawdust below exterior wood in this state.
They tunnel into wood to nest, boring roughly an inch in before turning to run along the grain. Inspectors examining a property look for those round 3/8-inch holes in eaves, fascia, decks, and trim, checking exterior wood surfaces for active or previous activity.
Why this matters more than it sounds. Carpenter bees are a wood-destroying insect for reporting purposes — the NPMA-33 report covers termites, carpenter ants, carpenter bees, and reinfesting wood-boring beetles. So carpenter bee damage on your eaves appears on the report in a real estate transaction, and under the standard Northern Virginia contract the seller pays for treatment and for repair of damage the report identifies.
People discount carpenter bees as cosmetic. The contract does not.
Carpenter ants: the moisture signal
Carpenter ants excavate wood to nest rather than eating it, so their galleries are smooth and clean, and the material they push out includes recognisable insect parts and soil.
The useful inference: carpenter ants prefer wood that is already damp or damaged. Finding them frequently means finding a moisture problem — a leaking gutter, a failed flashing, a plumbing drip inside a wall — that has been running long enough to soften the wood.
Treating the ants without addressing the moisture generally produces their return.
Drywood termites: less common here
Drywood termites appear occasionally in southeastern coastal parts of Virginia. They do not require soil contact, which means no mud tubes, and their signature is the pellet.
If you find dry, hard, sand-like pellets accumulating below interior wood and returning after cleaning, that is worth an inspection promptly.
Not to be confused with the common species. The eastern subterranean termite is what most Virginia homes encounter, and it does not produce frass piles — it leaves mud tubes instead. Wings on a windowsill →
What to do today
Do not sweep it up yet. Photograph it in place first, with something for scale.
Collect a sample in a sealed bag or a small container. Frass is genuinely diagnostic — an inspector can often identify the source from the material alone.
Look up. Find the hole the material came from, and photograph that too. The shape of the opening is more diagnostic than the pile.
Then sweep, and mark the date. Whether it returns, and how fast, answers the main question.
Do not fill the holes yet. Sealing an active gallery traps the occupants inside and removes the evidence.
What this means for you specifically
If you own and live in the home
For carpenter bees this is a maintenance question — the damage accumulates slowly and repeat nesting in the same wood is the real cost. For carpenter ants it is usually a moisture question first.
Your action: identify the source before treating, and if it turns out to be carpenter ants, find the water.
If you are selling under contract
Carpenter bee holes in your eaves are a wood-destroying insect finding, and they will appear on the report.
The standard Northern Virginia contract obligates the seller to furnish a report dated within 90 days of settlement and to pay for treatment and for repair of damage the report identifies, with written evidence before settlement.
Your action: deal with it before the inspection rather than after. Exterior trim repair is straightforward when it is not on a settlement deadline. The contract clause →
If you are buying
Ask specifically whether exterior wood was inspected and what was found. Carpenter bee damage is easy to see and easy to overlook.
Your action: read the obstructions section of the seller's report, and check the eaves and deck yourself. Reading the report →
If you rent
The structure is the landlord's responsibility through the habitability duty under Va. Code § 55.1-1220, and your duty under § 55.1-1227 is to report promptly.
Your action: notify the landlord in writing today with photographs. Step by step →
Before you call: what costs what
An inspection and a treatment are two separate services with separate prices, and conflating them is the most common way people end up surprised by a bill.
| Typical Virginia range | What it produces | |
|---|---|---|
| Wood-destroying insect inspection and report | $65–$200 | the NPMA-33 form |
| General pest inspection | often free where the company expects to quote treatment | a verbal or written assessment |
| Termite treatment | $500–$2,000; more where damage is extensive | a treatment record |
| Structural repair | quoted by a contractor, frequently the largest of the three | an invoice, not a pest control document |
What is usually free: a quote for treatment, once a company has seen the problem.
What is usually not: the inspection report used in a real estate transaction, and any visit that produces a document rather than a price.
Ask which applies before you book. A company quoting one figure covering both inspection and treatment is not quoting what a sales contract or a lender requires.
Common misunderstandings
"Sawdust means termites." In Virginia it most often means carpenter bees. The common local termite leaves mud tubes, not frass.
"Carpenter bees are harmless." They are a wood-destroying insect for reporting purposes, and repeat nesting in the same wood compounds over years.
"I'll just fill the holes." Sealing an active gallery traps the occupants and destroys evidence. Treat first, seal after.
"It's from the contractor." Possible — and testable. Construction debris does not come back.
"A small pile means a small problem." The pile is what was ejected, not what was excavated.
"Painting the wood will stop them." Painted and sealed surfaces are less attractive to carpenter bees than bare wood, but it is prevention rather than treatment.
What to ask the inspector
- Can you identify the source from the frass itself?
- Is this activity current or historical?
- If carpenter ants: where is the moisture coming from?
- How much wood is affected, and what needs opening up to establish it?
- What is the treatment, and does it include sealing the galleries afterwards?
- Will this appear on an NPMA-33 report if I am selling?
- Under what name is your Virginia pesticide business license held?
That sixth question matters if you are anywhere near a transaction. The answer is usually yes.
What to have ready
Property address and year built, where the pile is and what is above it, whether the wood is interior or exterior, whether the pile returns after cleaning and how fast, whether there is any known moisture problem nearby, and your settlement date if you are under contract.
Frequently asked questions
How big are carpenter bee holes? Round, smooth, and about 3/8 inch — distinctively neat, as if drilled.
Do carpenter bees sting? Males are territorial and hover aggressively but cannot sting. Females can but rarely do.
Is drywood termite frass dangerous to handle? It is insect waste; ordinary hygiene applies. Bag it rather than sweeping it into the air.
Will an inspector look at the eaves? For a wood-destroying insect report, exterior wood surfaces are part of the inspection.
Can I treat carpenter bees myself? Products exist. Whether they resolve the problem depends on how many galleries there are and how long the wood has been used, and a treatment record from a licensed operator is what a transaction requires.
Verify before you pay anyone
VDACS maintains a public pesticide search at pesticidesearch.vdacs.virginia.gov and publishes an updated list of licensed pesticide businesses weekly. Wood-destroying pest control is category 7b under 2VAC5-685-70.
Ask which name the license is held under. How to check →