7 Warning Signs of Woodworm Infestation in Your Home

Woodworm infestation is a common problem in many UK properties, particularly in older homes with exposed timber structures. The term “woodworm” actually refers to the larvae of several species of wood-boring beetles that feed on timber as they develop.

If left untreated, woodworm can weaken structural timbers, floorboards and roof structures. The key to protecting your property is identifying the signs early so the infestation can be properly assessed and treated.

Here are seven warning signs that may indicate woodworm in your home.

1. Small Round Exit Holes in Wood

One of the most recognisable signs of woodworm is the presence of small round holes in timber surfaces. These are known as exit holes, created when adult beetles emerge from the wood after completing their life cycle.

These holes are usually around 1–2 mm in diameter and may appear in:

• Floorboards
• Roof timbers
• Wooden beams
• Furniture
• Skirting boards

While the holes themselves are small, they often indicate that larvae have been feeding inside the timber for some time.

2. Fine Powdery Dust (Frass)

Another common indicator of woodworm activity is a fine powdery dust known as frass. This material is produced when larvae tunnel through the wood and push waste out of the exit holes.

Frass often looks like very fine sawdust and may accumulate beneath affected timbers or around small holes in the wood.

If you notice fresh dust appearing regularly, it may suggest that the infestation is still active.

3. Weak or Crumbling Timber

Over time, woodworm larvae can significantly weaken timber structures. Affected wood may become soft, brittle or crumbly as the internal structure is gradually eaten away.

In severe cases, floorboards or beams may feel unstable or begin to break apart.

This type of damage should always be inspected by a professional timber specialist.

4. Damaged Floorboards

Woodworm commonly affects timber floorboards, especially in older properties with suspended timber floors. Signs may include:

• Small holes in the boards
• Crumbling edges
• Sections that feel spongy or weakened

If the infestation has been present for some time, structural joists beneath the floorboards may also be affected.

5. Tunnels Visible in Exposed Wood

If damaged timber is cut or broken open, you may see a network of small tunnels running through the wood. These tunnels are created by larvae as they feed inside the timber.

This internal damage often extends further than what is visible on the surface.

6. Adult Beetles Around Windows

In the warmer months, adult woodworm beetles may emerge from timber and be found around windows or light sources. Seeing small beetles indoors during spring or summer can sometimes indicate that woodworm is present within the property.

However, the presence of beetles alone does not always confirm an active infestation, so further inspection may be required.

7. Timber Located in Damp Conditions

Woodworm is more likely to develop in timber that is damp or poorly ventilated. Areas of a property that commonly experience these conditions include:

• Roof spaces
• Basements and cellars
• Sub-floor voids
• Poorly ventilated rooms

Addressing moisture problems can be an important step in preventing further timber decay and infestation.

Why Professional Inspection Is Important

Not all holes in timber indicate an active woodworm infestation. In some cases, the damage may be historic and no longer active.

A professional timber survey can determine:

• Whether the infestation is active
• Which species of wood-boring beetle is present
• The extent of any structural damage
• The most effective treatment solution

Correct diagnosis ensures that the appropriate treatment is carried out and prevents unnecessary work.

Woodworm Treatment and Timber Protection

Professional woodworm treatment typically involves specialist timber preservatives designed to eliminate larvae and prevent further infestation.

At Shield Waterproofing & Preservation, our experienced surveyors carry out timber inspections and woodworm treatment across many areas including Potters Bar, Nottingham, Kings Langley, Shrewsbury and surrounding towns.

Concerned About Woodworm in Your Property?

If you’ve noticed any of these warning signs, it’s best to have the issue assessed before the damage worsens.

A professional timber inspection can identify whether woodworm is active and recommend the most effective treatment to protect your property.