How Quickly Does Woodworm Spread? Room, House & Furniture

One of the first questions after finding woodworm is always: how fast will this get worse? The honest answer is that woodworm spreads more slowly than most people fear — but more insidiously, because most of the spreading happens invisibly inside timber over years, not weeks.

Understanding how and when woodworm spreads helps you judge how urgently to act — and what actually needs treating.

Does woodworm spread from room to room?

Yes — but slowly and in a specific way. Woodworm does not migrate through walls or across floors. It spreads when adult beetles emerge from one area of timber, fly to another area and lay eggs. The process looks like this:

1. Adult beetles emerge from infested timber in May–September
2. Adults are attracted to light and will fly to windows — and from there, potentially to other rooms
3. Females seek out unfinished timber surfaces to lay eggs — ideally in cracks, crevices and rough-grained wood
4. Newly hatched larvae burrow immediately into the new timber and begin feeding

The critical factor is whether there is accessible, unfinished timber in the new location. A painted, sealed floor is much harder for a beetle to colonise than rough, unfinished joists in a sub-floor void. Adult beetles emerging from a loft space can potentially colonise floor joists beneath, but they need to find suitable egg-laying sites.

In practice, a woodworm infestation in an attic does not typically appear in ground floor furniture within a season. But over multiple beetle generations — five, ten, twenty years — an untreated infestation in roof timbers can gradually seed downward through the building.

Does woodworm spread to other furniture?

This is more common than room-to-room spreading. Adult beetles emerging from an antique chair or cabinet will actively seek other timber surfaces nearby to lay eggs. Furniture items stored close together in the same room — particularly in a humid, warm environment like a spare bedroom or antiques shop — can cross-infect readily.

Most at risk:

• Unfinished undersides of furniture, drawer bottoms and runners
• Old, unvarnished or waxed antique pieces
• Furniture stored in damp, poorly-ventilated rooms

Less at risk:

• Painted or lacquered surfaces — females avoid smooth painted surfaces for egg-laying
• Modern furniture made from kiln-dried softwood or MDF — kiln-drying kills any existing larvae, and MDF offers no nutrition

If you find woodworm in one piece of antique furniture, inspect all other wooden pieces in the same room carefully — particularly anything unfinished or stored in contact.

How fast does woodworm damage timber?

The larvae cause damage at a rate determined by their development speed:

• A common furniture beetle larva bores approximately 0.5–1mm of tunnel per day
• Over three to five years of larval development, a single larva creates roughly 50–150cm of tunnel
• A typical small infestation of ten to twenty larvae can hollow significant sections of a floor joist over a generation

The insidious aspect is that the damage grows exponentially with each generation. A generation of twenty beetles produces potentially hundreds of larvae; those larvae produce a generation of hundreds of beetles. If left untreated over two to three life cycles, what started as a small infestation in one joist can become a building-wide problem.

Does woodworm spread to other properties?

The risk of woodworm spreading between separate properties is low in normal circumstances. Adult beetles do not typically travel long distances through the air to colonise new buildings. The most common route for spreading between properties is through infested furniture, antiques or second-hand timber:

• Moving infested furniture into a new home introduces adults and larvae
• Reclaimed or second-hand timber used in renovation can introduce infested wood
• Property-to-property spread via flying adults is theoretically possible in closely spaced terraces but is rare

How do I stop woodworm spreading?

1. Treat the active infestation

Professional permethrin spray treatment kills adults as they emerge and persists in the timber to kill adults over successive seasons. This breaks the life cycle and stops new eggs being laid.

2. Address the damp

Woodworm thrives in timber with elevated moisture content. Improving sub-floor ventilation, fixing rising damp and repairing leaking roofs removes the conditions that allow the infestation to persist. Many long-running infestations reflect a persistent damp problem rather than simple re-infestation.

3. Isolate infested furniture

If you have identified woodworm in furniture, move infested pieces away from other susceptible items during the flight season. Consider professional treatment or, for low-value items, disposal.

4. Inspect annually during flight season

From May to September, check for new exit holes and fresh bore dust in areas you have previously treated. A treated infestation that is eradicated should show no new holes in subsequent summers.

How urgent is woodworm treatment?

It depends on where the woodworm is and which species it is:

Location / Species	Urgency
Furniture, non-structural — furniture beetle	Low to moderate. Act within the season
Floor joists, rafters — furniture beetle	Moderate. Treat before spreading to new areas
Structural beams — furniture beetle	Moderate-high. Structural risk increases with each generation
Any location — deathwatch beetle	High. Specialist assessment immediately
Roof timbers — house longhorn beetle	Urgent. Can cause structural failure

If you are uncertain about species or urgency, a free woodworm survey gives you a definitive answer — and is worth far more than a delayed decision on treatment.

Read more: Is woodworm dangerous? · Active vs historic woodworm · What to do if you find woodworm