Week 5 - Termite Proofing

Week Four 15 - 19 Oct

Day 18 - 20.  Another quiet week this week.  The only thing that happened around the house was the installation of the ant sheeting, quite a different technique from what my first house (in 1988) had which was a chemical barrier.

Day 21 &22.  The frames were supposed to be delivered on Thursday but my builder said the steel company have delayed delivery till Monday. 

Tip - Research the termite risks in your area and consider what treatment you need based on the local regulations and the risk you are wiling to take.

My Notes on Termites.  The issue of termite proofing is quite an interesting one.  In our current house the lower floor is all brick and the upper floor is hardwood.  The house was built in the 70s when they were still using quite ferocious termite proofing under pads such as heptachlor.  When not exposed to air it can remain in the soil effective for up to 50 years.  They no longer use these sorts of chemicals as exposure for people is cumulative but they are very effective.  That aside despite the strong chemical barriers used in the older buildings we still had a run in with termites in our current house which has made us very cautious about how we manage our risk prevention.

Around our current house all the appropriate precautions had been taken, there were no garden beds next to the house, there were concrete paths around the house, the paths had been drilled and retreated, both ourselves and those who lived here before us had records of regular checks and treatments done on the house.  Despite this about three years after we moved in we got termites.  Downstairs the previous owners had fitted pine frames - off the floor and surrounded by painted brickwork - that supported plasterboard to make the walls look "pretty" and hide the exposed brickwork.  We noticed a bit of damp in one of the corners where the slab is partly underground and thought it was just rising damp, but when we dug a bit into the plasterboard we found termites.  After getting a professional in we discovered they had come up beside the slab, between the plasterboard and brickwork and then into the pine frames.  Fortunately for us the pine frames were not structural and we caught them early.  To reduce future risk we ripped out all the downstairs plasterboard and pine, wet proofed, rendered and painted downstairs.  However it did teach us just how determined these little critters could be.

In addition to our own experiences we also had experiences of friends who had had termites in their houses and had suffered major structural damage necessitating thousands of dollars in repairs, particularly in one instance where they had got into support timbers and the roof.

Given we are in the "Very High" risk zone as shown on this map, we did some research on risks vs building requirements. There is some very good information for QLD and other states on the Termite .com website.

We identified that in QLD the standard treatment requirements for Australian houses is H3 for the exterior support walls in modern houses, noting softwood pine is the usual building material now.    Interior frames can be a lower grade H2.  Noting this is the Australian Standard and what I could not confirm is if the standard, partcularly for the interior wall frames was compulsory or not.  There are a number of houses being built around us where some or all of the wood frames on the interior walls are yellow not with the obvious green tint of the exterior wall frames.  I am not sure if that means a different treating product has been used or if the interior wall frames are untreated.

The treated timbers tend to be guaranteed for around 25 years - but we actually plan to live in the house for longer than 25 years so am not keen on taking that sort of risk with the structural integrity of our house particularly when we are old and have also read several stories of people who indicated they had termites in their new houses inside this timeframe.  Insurance also apparently does not usually cover termite damage.

I found the following information useful:

Timber Net. Timbers treated against termite attack must attain appropriate levels of treatment to suit the application involved. Further details are in AS1604 but a selection guide is shown below:

Application	Treatment Level
Interior, above the ground	H2 or H2F*
Exterior, above the ground	H3
Exterior in ground contact	H4 or H5**

NOTES:

* H2F is only resistant to termites below the Tropic of Capricorn.

** Use H5 where ground water is present.

The treatments for the timber is primarily through the use of CCA (a form of arsenic) although there are other treatments.  For those who want information about issues related to toxicity vs safety of this product the CSIRO site has some good information.  We were both quite comfortable with the use of CCA it was more the risk to timber itself that worried us, particularly if termites got into the supporting timbers or roof.

The research indicates that the chances of termites getting into steel framed houses is actually no less however the key difference is that they don't eat steel, so the damage they do tends to be to cosmetic fittings that can be replaced a lot more cheaply than structural supports.  If the infestation is significant and long lasting some damage to the steel can occur but this is rare.

Anyway so the final conclusion for us was that a steel frame and appropriate termite prevention treatments would be the best option.   Termite barriers have been placed around all the pipes and the mat laid in the area between the slab and the frame.  When we move in and before we start doing our landscaping we will put in a barrier of termidor around the outside of the house with permanent accesses for retreatment.