Timber isn’t the best material for landscaping.

I won't get termites in my retaining wall or garden bed, right? After all, it's treated!  

There is a certain amount of truth to this statement, however, other factors need to be considered.

• Ineffectiveness of treatments - Some treatments are not effective in the long term and require regular re treatment, which of course, in the "real world" is seldom done.

• Effective treatments can be dangerous - Some treatments effectively protect timbers from fungal decay and termites, however, they can be potentially more dangerous than we would like. (CCA)

1) Not all timbers are durable in the weather - Some timbers are able to withstand extreme weather and attack from pests, others, however, may not be so durable. 

Although some timbers are treated, this may preserve them for a period of time, these may not last extended period of time and may eventually fail to protect the timber.

Although this timber retaining wall was treated, after many years the treatment has failed to prevent fungal decay. Although no termites ate the timber, the fungal decay will eventually cause the timber to fail.

Other treatments may be highly effective, but may be dangerous. At the moment, an effective treatment for preserving timber against termite attack and fungal decay is Copper Chrome Aresnate (CCA). If you think that sounds a lot like arsenic, you'd be right! It's still used for preserving timbers found at your local hardware stores. We actually managed to find several examples in a local hardware store chain here in Australia. Similar treated timbers are easily sourced in the USA and other countries as well. 

Studies suggest that the arsenic in CCA treated timber can can leach out through physical contact and via water contact.

Whatever treatment may have been used on this retaining wall post was no longer protecting it from termite damage.

These Termites Schedorhinotermes Sp. were discovered in a timber retaining wall on Lake Macquarie.

The maintenance program on this timber retaining wall was not regular enough to prevent fungal decay.

Spotlight on Treated timber - Copper Chrome Arsenate. (CCA)

Isn’t arsenic a thing of the past? No, it’s still commonly used and you may find that it’s found in more places than you’d think.

A timber retaining wall such as this one is a common use of Copper Chrome Arsenate treated timber.

Where will i find Arsenic around my home?

The most likely place is in treated pine sleepers. The arsenic is in the preservative treatment for the timber in the form of compounds of Copper, Chromium and Arsenic. The Copper prevents fungal attack, the Arsenic prevents insect (like termite) attack on the timber and the Chromium binds these two to the timber. It certainly is effective in preventing termites and other timber pests, but that’s not the scope of this post.

What does CCA treated timber look like?

CCA treated timber must be labeled as so when being sold prior to use, so you will likely see a label to that effect. Once in situ, the timber has a greenish tinge when newly treated, this will fade over time.

This H4 treated timber is clearly labeled as treated with Copper Chrome Arsenate.

What are the risks?

Should I be worried about using CCA treated timber?

CCA treated timber is hazardous, and as such, in 2005 the Australian Pesticides and Veterinary Medicine Authority advised that timber containing CCA is not to be used for high contact structures such as playground equipment. Additionally on the 1st July 2012, new restrictions were in place which stipulates that CCA treated timbers need to be supplied to, and used by suitably qualified individuals based on the authorisation provided by a relevant state or territory law.

This wording can seem ambiguous and difficult to decipher, however, in simple terms: in our experience, at the time of writing, in NSW, Australia, CCA treated timber is readily and easily purchased from local hardware suppliers with little, if any enquiry or determination of the suitability of the material for such use. As a case in point, a client of ours purchased and built a cubby house for their children with CCA timber on the “window sill” of the cubby house. A high contact area!

A Cubby house Built with CCA treated window sills.

Is it safe for my child to play on CCA Equipment?

According to International studies, children playing on CCA treated timber play equipment contributes between 2–8 per cent of the safe daily acceptable limits set by the World Health Organisation. It also is within the safe daily acceptable limits set by the Australian Department of Health and Ageing.

What can I do to protect myself and my family?

There is much research into the effects of CCA when touched through normal use in timber structures, and the statistics and conclusions vary. However, based on the Western Australian Department of health, there are some minimum precautions that can be taken.

1. Wash children’s hands after using play equipment.

2. Put food onto plates and napkins rather than directly on a wooden picnic table.

Additionally, some research suggests there is some benefit in painting timber to limit exposure to arsenic, painting with an oil based paint or stain may reduce the exposure. The coating will need to be applied every 12-18 months.

When it comes to raised garden beds, if you’re using CCA treated timber for your vegetable garden, you may want to line the inside with plastic before adding soil and keep plants away from the edge of the garden bed. Although the preservative is designed to remain locked in the timber there could be some leeching. This will help minimise edibles absorbing preservative compounds from the timber.

This vegetable garden bed could do with some lining to minimise any preservatives from the timber entering the edible plants!

Should I get my own timber pest inspection report?

When purchasing a home, a building and timber pest inspection are required to find out if there are any problems with the structure or if there are any timber pests.  

Who should organise this? 

Inspections can be organised by a number of parties, but some present a conflict of interest.

i) The Vendor - The vendor is ideally looking for a report that says the home has a "clean bill of health"; as such, if they engage a pest and/or building inspector, there is a possibility that the inspector is put under duress to present the report in the most favourable possible light. 

ii) The real estate agent -  is looking primarily after the interests of a vendor. By definition, the real estate agent has the primary role of selling the property. If they engage an inspector, they could possibly try to engage one that will be more "easy going", less fastidious in finding potential problems with the property. 

iii) The purchases conveyancer - If you're buying, then your conveyancer may organise the Inspection as a matter of due diligence. This wholesale outsourcing of inspections can present a problem if the inspector is possibly asked to provide cut price inspections or is too busy to perform thorough inspections. Although acting in your behalf, it's just a matter of a few minutes whilst your discussing the purchase with your conveyancer to find out who they use and check a few reviews. 👌🏻

iv) The purchaser - this is the most ideal candidate for organising a timber pest and building inspection, but there are potential pitfalls. Often, the purchaser can be financially stretched to the limit, especially with real estate prices rocketing. The temptation can be to find the "best deal", not all timber pest inspectors are created equal. The cheaper the price, the quicker the report, the quicker the report, the greater the possibility something will be missed. You're better off spending a bit more and getting a quality, detailed report rather than a cheap one.  

Will your Inspection include photos and inform you of potential problems? The best way to know may be to organise it yourself.

There are potential problems in each of these scenarios, and not all inspectors are created equal, a conflict of interest can arise in each case.

Ideally, its best to look into each scenario and make an informed decision that you're comfortable with. In theory, there isn't a problem with each of these options, in practice, our experience has been otherwise. 

Either way, do your homework, use reputable, licenced and insured inspectors and your possibility of surprises will be reduced.  

The Area around the property should also be checked to reveal potential threats.

Signs of Termites in walls

How do you know if you have termites in your wall? 

There are tell tale signs that are specific to termites.

Cracking in walls can be a sign that something sinister is happening behind the wall. The mud spots confirm that it's termites.

Termites will always seal any opening with their mud, here you can see tightly packed mud filling in the gaps.

Subtle changes in timber cover strips can be a dead giveaway. Here the vertical timber strip and the one to the left has been eaten out, the strip on the right remains intact.

Inside this built in wardrobe you can see evidence of termite workings. There is a tiny bit of mud right in the middle of the corner at the top and spots of mud/mould is visible on the Left Hand side. This is a clear indication of termite activity behind the walls.

Delignification - or chemical defibration.

Chemical delignification is a process that breaks down the lignin in timber. Lignin is an organic polymer that acts as a glue in timber (amongst other things), giving structural integrity to cell walls and thus holding the fibres together. It's the same material that gets attacked by fungal decay. The result is similar, the timber loses its structural integrity and slowly flakes apart. 

Chemical delignification gives this roof batten its "hairy" appearance.  

Delignification is often found in roof timber battens as depicted in these pictures, being caused by chemicals in the air. Often it is found near heavy industry, major roads or not far from the Sea.  

If there is significant damage caused by delignification then it's best to get it checked for structural integrity by a builder, seeing that roof battens are often affected by this phenomenon, caution should be exercised when walking around on roofs.

This chemical defibration was discovered in Newcastle, an area with historically a lot of heavy industry and is not too far from the ocean!

See a video showing the obvious effects of chemical defibration on roof battens.  

Liquid termite treatment vs. Baiting

Here is a video on the differences of a liquid chemical treated zone versus a perimeter baiting system. 

The video is produced by Dow Agrosciences who produce the Sentricon baiting system, so although it is promoting baiting it does provide a good overview of the functionality of both systems.

Chemical Termite treatments after heavy rain and flooding.

Following the East Coast Low, heavy rainfall has battered a large portion of the East Coast of Australia. Many homes were flooded and a large portion of land was inundated with water, both moving and standing. Does this flooding and saturation affect chemical termite treatments?

A technical note from BASF regarding Termidor treatments can be found here.