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Is Delignification Destroying Your Timber Home?

Timber Delignification Can Silently Destroy Your Home

Sure, termites are the talk of the town when it comes to timber pests in Brisbane. But what if you were told that there was another erosive force with the potential to silently and catastrophically eat away at the timber in your house? Timber delignification is a stealthy foe when it comes to the structural integrity of your Brisbane property. Ignore it and it can quite literally ‘bring the house down’.

Knowing what delignification is, and how to protect your home against it, is a crucial to safeguard when it comes to buying and maintaining a Brisbane property.

What is delignification?

Picture this: Wood is made up of fibres running its entire length. They’re bonded together with a naturally-occurring polymer called ‘lignin’. It’s not just nature’s glue. It also performs a number of vital functions in live wood, helping transport moisture from the ground up to the foliage and helping the plant to withstand insects and diseases.

The crucial role of lignin doesn’t end when the tree is cut down and the timber harvested, though. It’s what continues to hold the timber together and enable it to bear immense loads.

Without the lignin, the fibres would separate out like frayed material, crumble and eventually turn to dust. That’s exactly what happens in the case of delignification. In some circumstances, delignification is desirable: It’s utilised in manufacturing, such as the chemical process for making wood pulp and paper. However, when you’re talking about a process that dissolves the lignin in the timber in the roof over your head, it’s a disaster waiting to happen.

‘Delignification of timber’, ‘hairy timber’ and ‘timber fibrosis’ are all terms that describe the devastating effect of airborne chemicals on timber, particularly in the context of the structural timbers commonly used in the construction of houses. If your home’s even partially constructed from timber, delignification is something you need to be on your guard against.

Common causes of delignification

Whilst delignification in nature can occur when wood is exposed to fungus such as white rot, chemical delignification of timber is fast emerging as a destructive force to be reckoned with in households across Australia. There are three main factors at play when it comes to timber delignification in Brisbane:

  • Proximity to the sea and exposure to salt in the air,
  • Close positioning of a home to major arterial roads and exposure to the increased vehicular pollution as a result; and
  • Proximity of the building to major chemical plants, industrial areas and factories.

Brisbane’s increasing urban sprawl means greater reliance on cars and trucks and additional major industrial activity. The load on the arterial roads connecting the port to the mines and the farms of the food bowl to the city gets busier by the day. It’s not hard to see why delignification of timber is giving termite damage a run for its money as a leading cause of timber decay in your local Brisbane neighbourhood.

Not all timbers are as susceptible to delignification as others. For example, delignification’s often thought to have a far more dramatic effect on softwoods than hardwoods, with Oregon being a major casualty of this chemical process. Knowing the type of timber in your roof space is important when it comes to guarding against delignification.

Why timber delignification can spell disaster for your home

As you’d imagine, anything that eats away at timber has the potential to grossly undermine its structural integrity. Timber that is load-bearing can be significantly weakened, even to the point of collapse over time. That’s something to really keep in mind when you’re talking about the timber in your roof. It’s the part of the frame that’s most susceptible to the sort of airborne chemicals responsible for delignification.

When you think about a house frame and roof that’s constructed from timber battens and rafters, anything that undermines or eats away at those timbers has the potential to bring the whole roof or a section of it, crashing down. Sure, it takes time for timber delignification to advance to the point of collapse. But when you’re talking about a process that can, even at a fairly early stage, cause slight movements in those timbers, you’re talking about an erosive force that can reduce the effectiveness of your roof in keeping water out, leading to leaks and the damage that they inevitably cause.

At its worst, delignification is a disaster waiting to happen, particularly in tiled roofs where the weight of the tiles and the effects of gravity conspire catastrophically to take advantage of any existing weaknesses. And that moment could be the very next time you step onto your roof or in the next major storm or wind gust.

Recognising timber delignification

Unlike some of the other problems you might come across in your Brisbane home, Delignification isn’t always easily recognised. It’s not out in the open. More often than not, it’s happening out of sight and out of mind up in your roof space. After all, how often do you get up into your roof and navigate the insulation and air conditioning ducting and cobwebs to really have a close look at what’s going on in the dark?

Preventing delignification

By the time your timber takes on the characteristic ‘hairiness’ associated with chemical delignification, the problem is usually extensive and very difficult to treat. Delignification can occur in areas of the roof space that may be difficult, even impossible, to access. In its earlier stages it might be mistaken for dust.

You can achieve some measure of protection by ensuring that your roof timbers are oiled (for example, with linseed oil), painted or otherwise sealed. This has the effect of reducing their exposure to the airborne chemicals responsible for delignification, but only where you can get sufficient access to get enough of a protective coating on all sides of the timber.

However, if you’ve got an existing property, there’s no guarantee that these preventative steps have been taken. In fact, if you’re a home-owner who’s adequately factoring-in the effect of chemical exposure over time by taking these steps, you’re probably the exception rather than the rule.

Treating timber delignification

In some circumstances, timber delignification can be treated. Treatment options depend on how extensive, accessible and longstanding the damage is. Some cases may call for the complete replacement of the timber in a section of your roof, which can be time consuming, inconvenient and absurdly expensive. However, that’s always a far better option than having a loved one injured or finding out too late that your insurance policy doesn’t cover the damage from this preventable pest of timber. If you’re worried about your existing property or looking to buy your dream home, you need to be vigilant about timber delignification and the exorbitant cost of rectifying the damage that it can cause.

Other reasons to be worried about timber delignification

Timber delignification is also the ‘canary in the mineshaft’ when it comes to pointing to other things you should be concerned about in relation to a property you’re thinking of buying. Significant delignification of the timber in a property should start your warning bells ringing, particularly if you care about your family’s exposure to airborne chemicals, pollutants and known carcinogens. Identifying it before you commit to buying a property might just give you a much-needed opportunity to run in the opposite direction.

Our professional building inspectors are experts at identifying timber delignification in Brisbane properties. Call Action Property Inspections today on 1800 642 465.


About Andrew Mackintosh

Andrew Mackintosh has been answering home inspection questions in the greater Brisbane area since 1995. He has personally carried out over 20,000 building inspections and is a licensed builder and licensed building inspector, Member of Queensland Master Builders Association & Institute of Building Consultants. Being the business owner and the inspector, Andrew is passionate about providing clients with excellent customer service, value for money, honest, unbiased, thorough inspection and reporting in a professional and timely manner to allow clients to make informed decisions when purchasing property.