What termite damage actually looks like
Termites eat timber from the inside and leave the outer skin. That is why damage is usually found by sound and touch, not by sight.
The reason you cannot see it
A termite working inside a skirting board or a stud is not trying to be secretive; it is staying inside its own humid environment. The result is the same either way: it eats along the grain, hollows out the interior. And leaves the outermost millimetre or two (the painted face, the varnished surface) untouched. From the room, the board looks perfect.
This is why almost every description of termite damage is about sound and texture rather than appearance. And why the damage is nearly always more extensive than the first look suggests.
The signs, in the order people usually notice them
- A hollow or papery sound when a skirting board, architrave or door jamb is tapped. Compare it with the same timber a few metres away; the difference is obvious once you have heard it.
- Rippled, blistered or sunken paint, sometimes described as looking like water damage. The surface film is unsupported and starting to deform.
- A surface that gives under thumb pressure and does not spring back, or a screwdriver that pushes in with almost no resistance.
- Doors and windows that stick or no longer sit square, when nothing else about the house has changed.
- Floors that feel spongy or dip underfoot, which points at bearers or joists rather than at the flooring.
- Mud in the damage. If you can see inside a broken section, termite galleries are typically packed and lined with soil and faecal material. This is the detail that separates termites from every other timber pest.
Telling it from the other timber pests
Three things eat structural timber in an Australian house, and their damage looks different:
| Pest | What the damage looks like | Exit holes? |
|---|---|---|
| Termites | Galleries following the grain, lined and packed with mud | No |
| Wood-boring beetles | Round tunnels with fine powdery frass | Yes: clean round flight holes |
| Fungal decay | Soft, discoloured timber that crumbles or cracks into cubes | No, and no galleries |
Mud in the timber and no exit holes is the termite signature. Borers and fungal decay covers the other two in detail. It is worth reading, because all three are found in the same damp, unventilated places and turning up together is common.
Cosmetic or structural?
Damaged skirting, architraves and door jambs are unpleasant and cheap to replace. Damage to bearers, joists, studs, plates, lintels, rafters or trusses is a different category, because those members are carrying load. And whether they still carry it safely is not a judgement to make by tapping. That is an engineer's assessment.
Because the surface stays intact, the extent found once linings come off is routinely larger than the extent estimated before. Treat any early figure as provisional. Repairing termite damage covers the order the work has to happen in: and it is not the order most people expect.
The one rule while you are looking
Do not open it up. Tapping is fine; pushing a screwdriver through a board to see how bad it is. Or pulling off a section of skirting, disturbs the colony and moves it somewhere concealed. Find it, leave it, and get it inspected while the evidence is still where it is.
Frequently asked questions
Can termite damage be repaired, or does the timber have to be replaced?
Non-structural timber is usually just replaced. Structural members may be spliced, sistered or replaced depending on how much section is left: that is a decision for a builder working from an engineer's assessment, not a judgement made by eye.
How fast does the damage happen?
It depends entirely on the species, the size of the colony and the moisture available, which is why no honest source gives you a rate. What is consistent is that damage is well advanced by the time the surface shows it.
The damage looks old. Do I still need someone to look at it?
Yes. Old-looking damage does not establish that the colony has gone, and if structural members are involved you need to know how much sound timber is left regardless of when it was eaten.
Sources
What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.
- Department of Health, Victoria. Pest control — termites
- Queensland Building and Construction Commission. Protect against termites — termite management systems and inspections