Woodworm in Your Home: What It Is, How to Spot It, and When to Act

Woodworm Is More Common Than You'd Think

Most homeowners don't think about woodworm until they're staring at a piece of furniture or a floor joist riddled with tiny holes. By that point, the damage is already done. The problem with woodworm is that it works quietly, inside timber, for months or even years before the signs become obvious.

It's particularly common in older London properties, where original Victorian or Edwardian timbers have been in place for over a century. Age alone doesn't cause infestation, but damp conditions absolutely do. And where you find damp, you'll often find woodworm not far behind.

What Actually Is Woodworm?

"Woodworm" isn't a single species. It's a term used for the larvae of several wood-boring beetles. The most common culprit in UK homes is the Common Furniture Beetle (Anobium punctatum), though the House Longhorn Beetle and Deathwatch Beetle also appear, particularly in older buildings.

The beetle lays its eggs in cracks or pores in bare, untreated timber. When the eggs hatch, the larvae burrow into the wood and feed on it from the inside. This stage can last anywhere from two to five years. The small round holes you see on the surface are exit holes — made when the adult beetle finally bores its way out to mate and repeat the cycle.

So if you're seeing holes, the infestation has already been active for a while.

How to Tell If an Infestation Is Still Active

This is where a lot of people go wrong. Holes in timber don't automatically mean you have a current problem. The infestation could have died out years ago, especially if the timber has since dried out or been treated.

Signs that suggest active woodworm include:

• Fresh, pale-coloured dust (called frass) below or around the holes — this looks a bit like fine sawdust
• Holes with clean, sharp edges rather than dark or dusty ones
• Live beetles near timber in late spring or early summer, which is when adults typically emerge
• Weak or crumbling timber when pressed

Old, dark-edged holes with no frass around them are often historic. That said, it's still worth getting them assessed, because fresh activity can start up again if the conditions are right.

Which Parts of the House Are Most Vulnerable?

Woodworm targets timber that's untreated and in a damp environment. In most properties that means roof spaces, subfloor joists, floorboards, staircase timbers and structural beams. Furniture is also at risk, particularly antique or second-hand pieces that haven't been treated.

Cellars and basements deserve a mention here too. In London properties with inadequate waterproofing, these spaces often have the humidity levels that beetles favour. Addressing the moisture problem is a key part of any long-term woodworm solution — treating the timber without dealing with the damp just means the infestation is likely to return.

What Does Treatment Involve?

Professional woodworm treatment typically involves applying a preservative insecticide directly to the affected timber. The solution penetrates the wood and kills larvae within it, as well as deterring any new beetles from laying eggs. In cases of severe structural damage, some timber may need to be replaced entirely before treatment is applied to surrounding areas.

A qualified surveyor will assess the extent of the infestation, identify which beetle species is involved, and determine whether any underlying damp issues need to be addressed at the same time. Skipping that moisture assessment is one of the main reasons woodworm problems come back after treatment.

If you've spotted suspicious holes in your floorboards or roof timbers, getting a proper survey done sooner rather than later gives you a much clearer picture of what you're actually dealing with.