Timber borer inspection and treatment

What are timber borers?

Timber borer is a general name for several beetles whose larvae feed and tunnel inside wood. Powderpost beetles, furniture beetles and European house borers affect different timbers and carry different levels of risk. Exit holes often appear when adults leave the timber, so their age and condition matter.

Signs they may be present

• Small round or oval exit holes.
• Fine powder or gritty timber dust, known as frass.
• Fresh material collecting below a hole after it has been cleaned.
• Timber that is soft, weak, crumbling or hollowed internally.
• New holes, adult beetles or faint scraping sounds from inside timber.

What you can do yourself

• Photograph the holes and any dust before cleaning.
• Note the hole size, shape and location, then watch for fresh material returning.
• Mark or date the edge of the affected area to help track change.
• Keep subfloors, roof spaces and other timber areas dry and ventilated.
• Store firewood away from the house and keep suspect removable items separate.

What to leave alone and when to call

Do not fill, paint, sand or coat the holes before the timber is identified. Avoid cutting into structural members or applying a general surface spray; the wrong product may achieve little and can make the evidence harder to read.

Arrange an inspection if fresh dust returns, new holes appear, several areas are affected or the problem involves flooring, roof framing, bearers or joists. Unusual borers in imported timber or live trees may need biosecurity advice before anything is moved.

How we investigate and treat it

1. 1

   Identify the evidence

   We compare hole size and shape, frass, timber type and damage pattern.

2. 2

   Check whether it is active

   Fresh dust, recent holes, beetles, moisture and spread help distinguish current activity from old evidence.

3. 3

   Assess the extent

   Affected and inaccessible areas are recorded, and timber that may need building or structural assessment is flagged.

4. 4

   Match the response

   Where treatment is warranted, it is selected for the borer, timber, finish and access. Some timber may need trade repair or replacement, with follow-up monitoring where appropriate.