What is this in my timber?

These are every reading the check can return. None of them is an identification. Only a licensed timber pest inspector standing in front of it can confirm what you have. What they do tell you is what the evidence is consistent with, and how much of a hurry you are in:

• Active subterranean termites. A mud tube that is damp, dark and intact is a working runway. Subterranean termites cannot cross open air without drying out, so they build a covered road over anything they cannot eat.
• Old, abandoned workings. Dry, pale, brittle tubes can sit on a pier for years after a colony has gone. But dry does not prove gone: it proves that route is not in use, which is a much weaker statement and one people talk themselves into.
• Mud packing in a joint or crack. Termites seal gaps in their workings with the same soil-and-saliva mix. Mud appearing in a joint, around a pipe or in a crack in render is the same sign as a tube, without the shape.
• Termite galleries inside the timber. Termites eat along the grain from the inside and leave the surface film intact, which is why the board looks perfect and sounds like a drum. If you can see into a broken section, termite galleries are packed and lined with mud.
• A wood-boring beetle. Clean, round exit holes with fine powdery frass and no mud. The question is almost always whether it is active: fresh holes look pale inside, and new frass reappears after you sweep it away. Old flight holes in old floors are very common and usually mean an infestation that finished decades ago.
• Fungal decay. Not an insect. A fungus digesting timber that has stayed wet. Soft, discoloured, crumbling or cracking into cubes, with no galleries and no exit holes. Sound timber kept dry does not rot, so decay always points at a water problem first.
• Ants, not termites. Check the waist and the antennae before anything else. A termite has a thick, straight body with no pinch and straight beaded antennae; an ant is sharply pinched and its antennae are elbowed.
• A termite flight from a mature colony nearby. Winged termites fly once, land, and break their wings off deliberately. A scatter of identical, equal-length wings is the residue. It proves a mature colony flew close by. Not that it is in your house, since alates are drawn to light from outside.
• Drywood termite pellets. Drywood termites push distinctive hard, six-sided faecal pellets out of small kick-out holes, so you get a small pile below the timber. They live entirely inside the wood with no soil contact, which makes soil barriers irrelevant to them and the treatment different.
• A moisture problem feeding all of it. Whatever the pest turns out to be, sustained damp is usually why it is there. A leaking tap or pipe, a downpipe discharging at the footing, a hot water relief line, an air conditioner drain, a blocked subfloor vent or a garden bed built over the slab edge.
• A nest in a tree or stump. Several Australian species nest inside a living tree, a stump or a piece of timber left in the ground. A nest in the yard is a colony with a food source beside your building, and it is exactly what an inspector wants to see intact.
• Nothing conclusive yet: widen the search. One ambiguous sign is a reason to look at the rest of the property, not to relax. Walk the perimeter, the subfloor and the yard for mud tubes, tap the skirtings along external walls and in wet areas, and check anywhere timber meets soil.

⚠️ Whatever the reading, the first move is the same: leave it alone. Do not break it open, pull it off, poke it or spray it. Disturbed termites abandon the workings and rebuild somewhere else in the house. So a can of surface spray does not end an attack, it hides it and makes the damage harder to find.

Because in this subject the expensive mistake is not misdiagnosis: it is disturbance. A colony that has its workings broken open, or its foragers killed with a surface spray, seals off that route and re-enters the building somewhere concealed. You lose the evidence and you keep the termites, and the damage carries on out of sight.

It also breaks the treatment. Modern soil products and baits work by being carried back into the colony by the workers themselves. Kill the couriers and teach the colony to avoid the one place a technician could have reached it. And the strategy that would have eliminated it is much harder to run.

So each reading is marked with whether it is something you can confirm yourself or something that needs an inspector. And each one names the timber pest it points at. And every path ends with a line marked “This far”: photograph it, leave it, and get it looked at.