The difficulty with termite damage in Bali is that by the time it's visible, the infestation is usually well established. Termites consume timber from the inside, leaving the surface skin intact. A structural timber member that looks fine and sounds hollow when tapped can be 80% consumed internally. In this article I want to describe the early warning signs that indicate termite activity before significant structural damage has occurred.
Mud Shelter Tubes
Subterranean termites travel in sealed mud tubes that protect them from light and desiccation. These tubes are the clearest evidence of subterranean termite activity. They appear as brown, sand-coloured ridges running from soil level upward along walls, foundations, or structural elements. Tubes are often found inside wall cavities, under flooring, behind skirting boards, or in subfloor spaces. An active tube contains living termites — a broken tube will be repaired overnight if the colony is active.
Frass (Drywood Termite Droppings)
Drywood termites push their dry, pellet-shaped droppings out of the timber through small exit holes. Small piles or scatterings of uniform pellets on surfaces below timber members indicate drywood termite activity in the timber above. Pellets are oval, approximately 1mm, with six concave sides. They accumulate under roof framing, in corners below decorative timber elements, and under timber window and door frames.
Hollow-Sounding Timber
Timber that sounds hollow when tapped with a screwdriver handle or steel probe indicates internal consumption. Run the probe along the surface of suspected members — a change from solid to hollow sound locates the extent of damage. This test is most reliable on softwoods; dense hardwoods can mask hollow sounds.
Swarmers (Flying Termites)
Reproductive termites swarm to start new colonies, typically after the first significant rain of the wet season. Finding large numbers of winged termites — or shed wings — inside the building indicates an established colony nearby (usually within 50m). Swarmers are often mistaken for flying ants; the distinction is the waist (termites have no waist constriction) and the wings (all four wings of equal size in termites; unequal in ants).
What to Do If You Find Any of These Signs
Don't disturb the area or apply insecticide spray — this disperses the colony and makes treatment more difficult. Document the location with photos. WhatsApp us the photos and we'll advise the urgency and the appropriate next step based on what you're seeing.
How Termite Damage Progresses
Understanding the timeline helps explain why early detection matters so much. In the first months a subterranean colony establishes contact with the building and begins feeding inside a single timber member — invisible from outside. Over the following year the colony grows and spreads to adjacent timber, hollowing structural members while the surface stays intact. By two to three years, a vigorous colony — and Bali's warm soil keeps them vigorous year-round — can compromise load-bearing elements. Because nothing looks wrong until late in this sequence, owners routinely underestimate how long termites have been at work by the time they call.
What the Damage Costs to Put Right
The cost gap between early and late discovery is dramatic. Catch it early and you're looking at a targeted treatment and maybe one or two replaced members. Catch it late and you can be replacing structural beams, lifting and relaying floors, and re-finishing rooms — work that routinely runs into tens of millions of rupiah, plus the disruption and lost rental nights. The signs in this article are, in effect, an early-warning system that lets you act while the bill is still small.
Don't Rely on Sight Alone
One honest caveat: a visual scan, even a careful one, misses a lot. Termites work in concealed places — inside wall cavities, under floors, in roof voids behind insulation — that you simply can't see from a doorway. That's why these signs are a prompt to investigate, not a substitute for a proper termite inspection, which probes suspect timber and checks the hidden areas where active colonies most often hide. If you've spotted even one of the signs above, it's worth getting eyes on the parts of the building you can't reach yourself.
Found Something Suspicious?
Send us photos on WhatsApp — we can often give you an initial assessment from photos before arranging a formal inspection.
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