Wellingtons Borer Problem

Wellington is home to many beautiful older houses — from charming villas in Thorndon to weathered character homes in Newtown. But there’s one issue hiding beneath the floorboards and behind the walls in far too many of them: borer.

Borer (or wood-boring beetles) are a serious problem in Wellington homes, especially older ones. A lot of people are confused about why they’ve suddenly discovered tiny holes in their timber or noticed soft spots in their floorboards. The truth is, borer infestations are very common in Wellington, and it comes down to a combination of factors unique to the area and its housing history.

Here’s why borer are such a problem in Wellington:

1. Untreated or Poorly Treated Timber

A massive percentage of Wellington homes — around 40% of the housing stock — were built before the 1950s. At that time, timber was not treated with preservatives the way it is today. Timber like rimu, kauri, and mataī was widely used for framing, floors, weatherboards, and joinery. While beautiful and durable in many ways, this timber was often left untreated, making it a prime target for wood-boring insects.

Even when treatment was introduced, it wasn't always effective or long-lasting, especially when applied poorly or used in humid conditions. Without a protective barrier, borer larvae can easily burrow into the wood, remaining hidden for years while slowly damaging the structure from the inside out.

2. Moisture and Poor Ventilation

Many Wellington homes were built in a time when ventilation standards were minimal, particularly in subfloors and roof spaces. Add in Wellington’s famously wet and windy climate, and you've got the perfect conditions for borer to thrive.

High levels of moisture in the timber make it easier for female beetles to lay their eggs, and for larvae to tunnel through. Common causes of excess moisture include:

• Leaky roofs or flashing
• Poor subfloor ventilation
• Blocked or missing vents
• Lack of insulation and underfloor lining

In some hillside suburbs, homes are built directly into damp soil or have areas with minimal airflow — making the timber stay damp year-round. Borer absolutely love that.

3. Lack of Regular Treatment and Maintenance

Let’s be honest — maintenance wasn’t always a top priority for past generations. Many Wellington homes have been passed down or rented out with little attention given to what’s happening beneath the surface. Over time, the lack of regular timber treatment and monitoring has allowed borer populations to build up.

While modern pest control methods can stop an active infestation and protect timber, many homes have never had a proper inspection or professional treatment done. Once borer are in, they can continue their lifecycle quietly for years. Their larvae can live inside timber for 2 to 4 years before emerging as adult beetles.

Without intervention, each new generation just keeps eating away at the timber.

4. Infestations Passed On Over Time

Because borer has become so widespread in Wellington, many homeowners unknowingly inherit the problem. Sometimes it’s furniture brought in from another property. Other times, it’s simply because the infestation next door was never treated.

Adult borer beetles can fly short distances, especially from house to house in densely packed neighbourhoods. Once they land on untreated or damp wood, they lay their eggs — and the cycle begins again.

This means even if your house is fairly well-maintained, you're not completely safe if nearby properties are infested. That’s why professional treatment and sealing is essential to break the chain.

So What Can You Do About It?

If your Wellington home is older, or you’re seeing signs like tiny round exit holes, sawdust (frass) under timber, or soft patches in your floorboards, it’s worth getting an inspection.

At Total Pest Control, we specialise in borer treatment for Wellington homes using safe, low-toxic products that soak into the timber and kill larvae before they can do more damage. We can also advise on ventilation improvements, moisture control, and how to keep the pests from spreading to other areas of your property.

Don’t Ignore the Signs

What looks like a few tiny holes now could be serious structural damage in a few years. Borer might be common in Wellington, but that doesn’t mean you have to live with it.

Give us a call today to book a borer inspection, or visit our website to learn more about how we protect homes across Wellington, Lower Hutt, and the surrounding areas.

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