Treated H2 timber framing is a time bomb with no benefit.

The near-universal use of H2 blue, green or red framing timber in construction is now a time bomb for landfill in 20-40 years’ time. It cannot be composted nor recycled, and thus is sent to landfill. In an ideal world, buildings would be carefully deconstructed and every skerrick reused, but in the Land of Oz, where labourers are paid $55 per hour, and landfill rates are less than $200 per tonne that is just a pipe dream. 

H2 timber is marketed by leveraging the not unreasonable fear of termites. 

How can something so small cause so much fear? Yet the misunderstanding in the general public’s minds is probably second only to that of the great white shark. Without termites, it has been calculated that we would be smothered under three metres of rotting timber. How that was calculated would make interesting bedtime reading. 

The timber industry sells H2 as added termite protection, and a value-add. Quizzing a few suppliers I have been told the scale of production is such that it adds 20c per lineal metre to the cost, but I suspect that is optimistic. The building industry then on-sells it as added peace of mind for homeowners, but if we look more closely at the details, that’s often misleading, and unnecessary in any case.

For starters, Australian Standard 3660.1-2000 basically states that termites are to be kept out of the structure of buildings.  It sets out the requirements and various means for achieving this and, if followed, termites cannot get past effective barriers, so what is the point of having termite resistant framing within those barriers? 

Note that AS3660.2 says that regular inspections are required to complement the physical barriers installed in the building, and no more than 12 months apart. 

If the inspection regime fails, and termites work around the barriers and enter the structure, even if they cannot eat the framing, they will eat everything else, from the paper on the plasterboard to the engineered floor overlay to the bookshelf and the books on it. I’ve seen it happen. 

The marketing implies, though never quite states, that this supposed belt and braces approach would be a better outcome in that circumstance. But would it happen that way? – or should I say, wood it? Let’s look at what the fine print says in the instructions for use, and what actually happens on site – or at least, 99.99 per cent of sites.

Any exposed cut ends, which are by definition untreated, like the ends of top and bottom plates, must be sealed with an appropriate toxic chemical liquid. 

To quote one manufacturer’s technical bulletin: The recommendation of AS 1604.1 for all treated products in the hazard classes including H2 and H2-F is that good building practice is to reseal with a suitable timber preservative, such as Protim Solignum XJ Clear Timber Protective or Tanalised Enseal Clear. To meet the conditions of the chemical guarantee, minimum reseal requirements apply (refer Table 3, CHH Laserframe Product Guide) 

Likewise notches, chasings and other cut penetrations must be resealed, though the details vary between manufacturers.

Have you ever seen this happen on site? I never have, though I’m happy to believe there are one or two builders out there who do this. Post their details in the comments section please! 

So, in reality, the so-called security being sold to consumers is false – any claim for termite attack will be rejected once the forensics find all that untreated end-grain.

Meanwhile, with the average Australian building having a life expectancy of 42 years, we are lining up to fill all our landfill sites with uncompostible treated timber. 

Just sayin’…


Dick Clarke is principal of Envirotecture, is an Accredited Building Designer with over 35 years experience, focusing exclusively on ecologically sustainable and culturally appropriate buildings.

Spinifex is an opinion column open to all our readers. We require 700+ words on issues related to sustainability especially in the built environment and in business. For a more detailed brief please send an email to editorial@thefifthestate.com.au

17 replies on “Treated timber and termites? Why bother and why not to bother”

  1. As a long time, timber recycling specialist who has worked with many recyclers around Australia I can categorically state that H2F treated pine, despite the clickbait headline and some comments, is neither “a ticking time bomb” nor “the next asbestos”. Recovery of offcuts of H2F treated pine has increased rapidly over the last decade. It can be safely utilised as a fuel in energy recovery facilities, recycled into new particleboard and even used in some animal bedding products.
    This 2010 report backs this up with some science by well-respected researchers: https://www.fwpa.com.au/images/marketaccess/Final_report_-_Review_of_PN09_1074.pdf
    E.g., “The preservatives used are environmentally benign biocides, such as permethrin for insect control which has low mammalian toxicity. The synthetic pyrethroids have varying levels of permanence in the environment but all of them degrade due to environmental effects with time.”

  2. Treated timber should be banned, it can’t be disposed without causing environmental damage.
    A full switch to steel framing or masonry construction, there are plenty of solutions to the “termite” problem that don’t require poisons to be distributed through the environment.
    If it requires a more costly construction profile so be it, we don’t need any more Asbestos’s, Fire Retardant Chemicals.

  3. Hi Dick,

    Thanks for the article. I will leave it to others should they wish to comment on the remedial treatment of cut ends on H2F treated (termite-South of Tropic of Capricorn) framing timber, other than to say that Standards often take a precautionary approach. As someone involved with the development of Australian Standard AS1604, the independent performance evaluation trials assessed by the the Australian Pesticide and Veterinary Medicine Authority (Govt. regulator of wood preservation chemicals) for regulatory approval of bifentherin and permethrin (H2F treatment chemicals) had exposed untreated cut ends. There was no termite attack to the exposed untreated cut ends, showing the effectiveness of these treatment chemicals in resisting termite attack.

    In regard to the disposal of treated timber in landfill, there is some interesting and exciting research taking place on the potential to recover treated timbers from waste streams (including demolition waste streams) and use this for feedstock in the manufacture of new termite resistant particleboard. Using recovered treated waste material will alleviate or reduce the need to add new preservative chemicals to reconstituted wood based products, reduce the amount chemical usage and reduce the amount of treated timber in landfill. It may even lower the production cost of termite (H2) treated particleboard. More importantly, particleboard itself is readily chipped and recycled back into new particleboard when its useful life is completed. Early days just yet, but a promising piece of research.

  4. Amazing. The use of steel, bricks and block are all significant C02 producers.

    we should use modular timber products. Treat when pre cut to minimise treated waste.
    Use heavy CCA treatment so stored CO2 is always retained by not decaying.
    CCA is a highly insoluble chemical when bonded to timber.
    Re use modular products to provide economic building processes as the clients needs change.
    We have done this for 45 years.
    NZ is lucky not to have a big termite problem.

    1. Rod,

      H3 products complying with Australian Standard AS1604 used outdoors above ground should simply not be susceptible to termite attack. However, I do remember several years ago sampling treated product from the WA market stamped boldly as H2 (H2 indicates termite treated under Australian Standard). When chemically analysed, there was zero preservative in the product, a building disaster waiting to happen. When the importer was question on why the product was labelled H2- the response was H2 is the name of the overseas manufacturer. This was reported to building regulators in WA, but never found out the final outcome.

  5. I had one project that utilized belts and braces:
    • treated frame
    • underslab poisioning
    • exposed slab edge
    • treated penetrations
    • treated cladding
    The client rang me to tell me he had termites eating the wiring.
    Sure enough the new telsta cable drilled through the slab welcomed the termites in.
    With nothing to eat (and a leaking tap to provide water) they were eating the plasterboard and wiring.
    How happy was the client and I to have more than a treated frame?
    I did not have the trusses treated which they would have eventually gotten to.
    So I an afraid I have to disagree with Mr Clarke on this occaision.

  6. Sad to say but I’ve been boring people for years saying that CCA & H2 treated timber are going to be the next “asbestos” style disaster for the building industry. Ask James Hardie how that went for them.

    I’ve never understood why we aren’t using more cypress pine framing, no concern about, end grain cuts or holes from rough in there.

    Thanks
    great article btw

  7. Not to mention the particulate dust, swarf and chips produced in the construction process – how many chippies, builders, plumbers, electricians et al contain and use dust suppression ?
    Inhaled h2 dust may well be yet another health problem in future.

  8. As an advisor to the recycling industry I totally agree. The amount of CCA treated timber currently being landfilled is gut wrenching. It contributes to greenhouse gas emissions and leachate. H2 timber like CCA, already appears at timber recycling facilities and has to be separated for landfilling. That alone costs a fortune. IF there was a serious attempt to review the standards and provide alternative advice, please count on MRA Consulting to contribute.

  9. Does this termite chemical affect plants growing in soil polluted with remnant H2 landfill?
    The alternative is steel framing, which one would consider to be a valuable recycling commodity; though, it is such thin-wall and it is galvanised, so does that reduce it’s potential to be recycled into new, pure, steel?

  10. Very good article. The treatment of the cuts -as you stated – if not treated stops the ability of the timber to be impervious to bugs. I think its like Lynas’s security blanket- its a feel good. In this case makes consumers feel comfortable and safe.

  11. Hi Dick, I built my house in 1980 with untreated pine and the termite barrier was a spray of some nasty chemical underneath. It worked well until the Newcastle earthquake shook the house and opened a gap on the slab. The termites came and ate firstly the skirting boards then bits of the the pine that I only discovered when the door would not close because the beam above had sagged.

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