That Dust on Your Floor — Termite Frass or Ant Frass?

Finding fine dust or powder near skirting boards, doorways, or timber is a common homeowner panic moment. The immediate assumption is often termites. Most of the time, it isn't. Understanding what you're actually looking at determines whether you need an inspection now, a pest treatment, or nothing at all.

There are three sources of dust or powder that come up regularly: ant frass, termite workings, and borer frass. They look different from each other, and they mean different things.

Ant frass — what it looks like

Ant frass is fine, black, and dusty. It looks like finely ground pepper, or very fine dry soil. It falls in small piles or lines, often near skirting boards, doorframes, wall junctions, or on window sills. If there's an active ant trail nearby, you're almost certainly looking at ant frass.

The frass falls as the ants excavate — they're removing material from galleries as they build nests or expand existing ones. The piles reappear after cleaning if the ants are still active. You might also find fine wood fibres or insulation material mixed in, depending on where the ants are nesting.

If you find fine, dark, powdery dust and an ant trail: it's ants. A general pest treatment deals with the ants; it doesn't require a termite inspection.

Termite frass — what it actually looks like

Here's the diagnostic: termite frass is not fine powder. It is brown mud — solid in texture, not dusty.

Subterranean termites in Sydney work inside timber, packing their galleries with a mixture of soil, frass, and saliva — the same earthen material they use to build their mud tubes. What comes out of termite activity isn't loose dust. It's brown, clay-like, and has a solid or granular texture. You might find it pushed out of small holes in timber, or packed into an exposed gallery during renovation work.

The powder on your skirting board is almost certainly not this.

Where termite activity is present, the more visible signs are usually mud tubes — the brown earthen tracks running from soil or pier surfaces up toward timber — or hollow-sounding timber that flexes under finger pressure where it should be firm. Those are the signs that trigger an inspection.

If you've found something that looks like brown mud near timber, or hollow timber, call for an inspection. Termite Inspections

Borer frass — the third option

If the powder you've found is pale-coloured — cream, buff, or very light brown — and it's falling from or surrounding small round holes in timber (typically 1–3mm diameter), you're looking at borer frass. Wood borers are beetle larvae that tunnel through timber; the holes are exit holes left when the adult beetle emerges.

Borer frass is very fine-textured. Lyctus (powderpost beetle) frass is almost talc-like in fineness; Anobium (common house borer) frass may be slightly coarser. Both are pale-coloured. Both come from visible round holes.

Active borer frass — fresh powder accumulating below holes — means the infestation is ongoing. Old, dusty holes with no fresh powder below them may be historic activity that has already run its course (particularly Lyctus in older timber). An inspection determines whether the activity is current.

When the dust matters and when it doesn't

Fine, dark, dusty powder + visible ant trail: Ants. General pest treatment. No termite inspection needed unless there's another reason to suspect activity.

Brown mud near timber, or hollow timber anywhere in the house: Inspection immediately. Don't disturb anything; call a pest specialist. Termite Inspections

Pale, very fine powder below small round holes in timber: Borer activity. Inspection to determine species and whether activity is current. Most cases: replacement of affected timber + moisture source fix.

Pale powder with no holes visible: Could be paint, plaster dust, or dry wall compound. Look for round holes in the nearest timber surface before assuming borers.

The diagnostic alone is worth knowing. Most "termite dust" calls turn out to be ants or borers. When the brown mud appears, that's when it's urgent.

Next step

If you've found something and you're not sure, a call is the fastest way to get clarity.

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