How do I identify and treat woodworm in secondhand furniture?

As consumers search for affordable or vintage items to decorate their homes, one of the most popular pre-owned product categories is furniture.

While purchasing secondhand items can be a cost-effective and environmentally friendly option for homeowners, it may also carry unforeseen risks, as the period from April to September is typically prime time for larvae to emerge as adult beetles. Therefore, those buying secondhand wooden furniture must be aware of the potential damage that woodworm can cause when infested items are unknowingly brought into the home.

Here’s how to tell if you have woodworm in your home, and exactly what to do to treat it so it doesn’t cause any substantial damage down the line.

What is woodworm and how can you identify it?

Woodworm are the larvae of wood-boring beetles that burrow into wood, causing damage to its structure over time. They enjoy nothing more than to chew their way through large wooden structures such as staircases, roof timbers and joists, but are equally happy to settle in smaller wooden items, including furniture.

While few of us think to look for signs of woodworm while purchasing used furniture, there are a few key clues that can give it away – you just need to know what to look for. For instance, always check the ply backs of wardrobes and ply base to drawers as Common furniture beetles, in particular, enjoy ply. In the same way, any wicker item can also easily become infested as it is all nutritious sapwood.

Identifying a woodworm infestation in furniture can be tricky, especially in furniture that has been painted or varnished. One of the most obvious signs of woodworm are “flight holes” left in timber, often caused by the Common furniture beetle (Anobium punctatum). During ‘woodworm season’ it is not uncommon to notice these small, round holes (around 2mm) appearing in woodwork as the adult beetles emerge – after which they can continue to live for days or even months. These holes will look fresh, without paint or dust in the hole.

As woodworm larvae feed on wood, they produce fine sawdust or frass (droppings) that may accumulate near the infested area. Look out for small piles of sawdust or frass around wooden surfaces, especially near flight holes. This may be a sign that larvae have hatched from eggs and are feeding on the wood.

How does woodworm affect your furniture? 

As the woodworm burrows into the wooden furniture, creating a network of tunnels, over time this can weaken the structural integrity of the furniture, causing it to become unstable or even collapse. 

Woodworm infestation can also damage the finish or varnish on the furniture’s surface. The larvae may tunnel just beneath the surface, which can result in a deteriorated and uneven appearance.

Several factors can increase the risk of woodworm infestation in furniture, including high levels of humidity or moisture. The more damp the wood becomes, the easier it will be for larvae to bore through and live in. Woodworm is less of an issue in wood with a moisture content less than 8-12 percent, making furniture stored in colder homes a breeding ground for woodworm with a typically moisture content of around 15 percent.

What to do if you suspect woodworm in your furniture

If you suspect that your furniture is infested with woodworm, it is important to act quickly. 

Firstly, it is strongly advised that the affected furniture is removed from your home to help minimise, or stop any further issues. Failure to address the issue can allow woodworm to spread to other wooden furniture or structures in your home. This perpetuates the cycle of infestation and increases the risk of damage to other items.

Removing moisture and humidity in the home will reduce the likelihood of a woodworm infestation, but most DIY products can help to treat localised infestations. However, as all preservatives are now water based, care must be taken when treating waxed or varnished items as water vapour can be trapped under the surface and cause darkening of the wood.

Depending on the severity of an infestation and how delicate the affected item is, there are also advanced technologies that can help. Professionals use Controlled Atmosphere Technology (CAT), which is a safe and effective method to treat such items. This method uses inert gases in a controlled atmosphere that eliminates all life stages of the insect, including eggs and larvae, while leaving no harmful residues on the furniture. The treatment also penetrates fabrics, so upholstered furniture can be treated without having to remove the fabric.

Professional Woodworm Treatment

If you are unsure how to treat woodworm infestation in your furniture, or if it is severe, it is best to seek professional help. An expert can help you identify the type of beetle causing the infestation and recommend the best treatment options to prevent the situation from worsening. When repairing antique furniture that has suffered woodworm damage, it is best to seek advice from restoration specialists.