Termites in a door frame: why the jamb is often the first place you notice
Termites do not prefer door frames. Door frames are simply the part of the concealed structure you put your hands on every single day.
Why does a door frame show termites early?
A door frame is one of the first places an owner notices termites, and the reason is position, not preference. The jamb is a tall, continuous length of timber that starts at floor level and is fixed back into the wall frame. The architrave then covers the gap between that frame and the wall lining.
That gap is a concealed vertical route running from the floor up. It is exactly what subterranean termites are looking for: a way to move inside the building without ever crossing open air.
So you are not finding them in the door frame because they began there. You are finding them there because a concealed run has finally reached a surface you touch dozens of times a day. A skirting board gets tapped once a year if it is lucky. A door gets opened, closed and latched constantly, so a couple of millimetres of movement or a soft patch under a thumb registers almost immediately. Door frames are an early-warning device by accident.
What does termite damage in a jamb actually look like?
Usually, like nothing at all. Subterranean termites eat timber from the inside and leave the outer film intact: the paint, the primer, the last millimetre of timber. They leave it because that film keeps the humidity in and the air out. So the frame can be substantially eaten while still looking freshly painted. What you are reading is small distortions of that surface:
- A hollow or papery sound when you tap the jamb or architrave with the handle of a screwdriver, compared with the same timber a metre away or the frame on the other side of the house.
- Paint that ripples, blisters or sinks in a band along the jamb, or a mitre in the architrave that has opened up.
- A jamb that gives under thumb pressure where it should be solid: often low down, near the floor.
- Mud. A crust of soil-coloured material in the joint between architrave and wall, packed into a nail hole or a crack, or a mud tube arriving at the frame from floor level.
- A door that has started to stick or drop when nothing else about the house has changed.
What termite damage actually looks like covers the same surface signs across the rest of the house.
Is the door sticking because of termites, or something else?
Most sticking doors in Australia are not termites. It is worth knowing what else fits before you assume the worst, and just as importantly, before you talk yourself out of a look.
| Cause | What it usually looks like | What separates it |
|---|---|---|
| Seasonal moisture movement | Sticks in the wet months, frees up in the dry ones, same edge every year | It comes and goes. The timber is still hard when you tap it |
| Ground or footing movement | Door and frame out of square together; cracks in cornices or brickwork nearby | The whole opening has moved. The timber itself sounds solid |
| Hinges or hardware | Screws loose in the jamb, one hinge pulling, latch no longer meeting the strike | Fixable with a screwdriver, and the timber around the screws is sound |
| Fungal decay | Soft, dark, often crumbling timber at the very bottom of an external jamb that gets wet | Damp and discoloured at the surface, not hollow behind an intact one |
| Termite activity | Hollow sound, rippled paint, thumb gives, mud in a joint: surface still looks fine | The outside is intact and the inside is not |
These are not mutually exclusive, and that is the catch. A frame that stays damp because of a leak or a blocked drain is both a decay risk and an attractant. And the two are regularly found together in the same doorway.
Which door frames are most at risk?
External frames at ground level come first. The classic case is a back or laundry door, especially where a paved path, a concrete slab, a garden bed or a run of mulch has been built up against the wall. That matters because the fill can cover the slab edge or bridge a barrier, and a visible approach becomes a concealed one. See how termites get into a house.
After that come doorways beside wet areas: bathrooms, laundries, kitchens, or anywhere a hot water unit or a leaking pipe has been keeping a wall damp. Next are garage and internal doorways where the frame sits directly on or against a slab. Last are doorways in a house with a subfloor, where the frame is close to a pier or a bearer that already has activity.
What not to do with a frame you suspect
This is the part that decides how the next six months go.
- Do not push a screwdriver blade, a knife or a nail into it to see how far it goes. That opens the gallery.
- Do not lever the architrave off to have a look behind. It is the single most tempting thing to do and the single most costly.
- Do not spray anything. No surface spray, no bug bomb, no home remedy poured into a crack.
- Do not fill it, sand it and repaint it. Cosmetic repair hides live evidence and the eating carries on underneath.
All four do the same damage. A disturbed colony abandons the route and re-enters the building somewhere concealed, so the feeding continues where nobody is looking. And the evidence an inspector needed to trace it back to the entry point is gone. Why spraying termites yourself makes it worse sets out what else it costs you, including the treatments it takes off the table.
What to do instead
Photograph the frame, including a shot that shows where it is in the house, and leave everything exactly as it is. Then book a timber pest inspection carried out to AS 4349.3 and tell them which doorway and what you noticed. A specific starting point makes the inspection better, not shorter. What a termite inspection covers explains what they will and will not be able to see.
If you want to look at the rest of the house first, do it the way the frame taught you: tap, do not probe, and touch nothing. Checking for termites yourself is that walk in full.
Frequently asked questions
The architrave sounds hollow but the door still works fine. Is that old damage?
It might be, and you cannot tell from the outside. Dry, empty galleries from an infestation that has gone and live galleries with workers in them sound much the same through a painted surface. Distinguishing live from old evidence is one of the specific jobs of a timber pest inspection, and it is done with moisture readings and movement detection rather than by tapping.
Can termites get into an aluminium or steel door frame?
They cannot eat it, but the frame is not the point. Termites use metal and masonry as a surface to travel over, building mud galleries up them to reach timber somewhere else: a metal frame fixed to a timber-framed wall still has plenty of timber behind and around it. A non-timber frame changes what they can eat, not whether they can get there.
Should I just replace the door frame if I find termites in it?
Not first. Replacing the frame removes the visible part of a problem whose extent is unknown and whose source is somewhere else. Usually the soil outside. The order that works is inspection, then a management plan for the colony, then repairs, so that the new frame is not put back into the same active situation.
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
- Standards Australia. Australian Standards (AS 3660 termite management, AS 4349.3 timber pest inspection)