On August 16th 2017, The Age contained a two-page article about 8,000 blocks in a new suburb called Mount Atkinson, situated between Caroline Springs and Rockbank in Melbourne’s outer west.
The Victorian government is proposing to create 100,000 such house blocks by the end of 2018, the article said.
Most of this proposed new suburb is at present basically grasslands, likely having trees marking some boundaries between farms. There is also a portion that is a winery with the peak of Mount Atkinson on the winery site. It is on Melways Map 357 and noted as being 140 metres high, so it’s not a mountain.
But it may well have been one or part of one thousands of years ago, and quite possibly a volcano. The soil is basically red.
The outer western suburbs of Melbourne are home to the volcanic loams that (along with soil reports wrongly based on the Ys estimation method to determine the soil classification) are responsible for thousands of soil-heave situations under waffle-pod slabs built during and after the longest drought in recorded history. That drought lasted about 14 years, ending just seven years ago.
During and since that drought, there has been virtually no official mention of the fact that soil testers (and later structural engineers and relevant building surveyors) failed to prevent thousands of house sites from being classified incorrectly by use of the Ys estimation method in the Code for Residential Slabs and Footings AS 2870. They classified the sites during conditions that were not ‘normal’ where the code clearly stated (and still states after 2011 revisions), that Appendix D of that code must be used instead. P classifications do not alter this situation.
As a direct result, there are already thousands of homes each with defects worth at least tens of thousands of dollars to rectify – some requiring complete re-building. Changes almost certainly will not prevent more such disasters.
The Federal and Victorian governments should have demanded that this code be changed to make it patently obvious that soil testers must use Appendix D of the code unless normal conditions are first proved to prevail on each site.
Instead there has been a revision of the code adding a quantity of informative notes which explain what normal conditions are.
Now trees, sun, wind and dry air associated with the drought took out moisture from the surface of the soils of these western plains for over 14 years in a row. And the soil deeper down (often to depths exceeding two metres) kept having to even up the moisture adjacent the dryer soils above. This is how clay soils work, and volcanic loams do it as well as any.
If it rains, the added moisture immediately starts to seep down lower and lower to even up the moisture. But when you get 14 years of continuous drought, the moisture flow is basically one way – out of the soil and into the air, in this case to record depths.
So if it took most or all of the 14 years of soil moisture reduction (drying out) to reach the bottom of the deep loam stratum, then it is likely to take a similar time (or possibly more) to again reach normal soil moisture levels deep down.
When you think about it, the weather really needs to be wetter than normal for something like 14 years on end to get back to normal conditions. Immediately after the drought, we had two such years.
But since 2012, our weather has actually been drier than average; 2014 and 2015 were under 70 per cent of our normal rainfall and 2013 and 2016 were just under 85 per cent. So recovery of moisture deep down may not yet have progressed far at all.
We will probably have to wait for well over a decade before we will again reach normal conditions. So heave is still very likely to occur on a large number of blocks in volcanic loams in the far west of Melbourne.
The revisions to the AS Code 2870 have not been accompanied by wording that stops the cheaper Ys estimation method from being used incorrectly. There was always a description of what constituted normal conditions. It’s just that now it’s supplemented by a large appendix at the rear of the code.
I wonder if it will actually be heeded, because soil testers will test for the very same builders who will want soil reports to remain inexpensive and footing systems that don’t blow the budget of their clients and cause delays.
They may not even consider the thinking process outlined above because it would be bad for their businesses, and business rules in Australia.
The government still seems hell-bent on keeping house prices as low as possible. They think that they will lose votes if young couples cannot afford to build their (rather large) dream homes, so don’t expect any help from them. Governments also protect business, often at the expense of building consumers.
These two agendas are built into virtually every piece of building legislation.
That is probably why no soil report writers were ever prosecuted by the VBA, even though they negligently arrived at the incorrect soil classifications for thousands of building sites, causing massive harm (via soil heave) to thousands of new (outer western suburbs of Melbourne) slabs and their home owners. The relevant building surveyors were no less negligent. Many if not all the structural engineers were also at least partly to blame by virtue of their civil engineering qualifications. By not refusing to design slabs on incorrectly stated ‘normal condition’ sites, they paved the way for use of the short-cut Ys estimation method.
So why would these registered building practitioners or soil report writers, who previously made serious mistakes, change and upset the apple cart when only builders have been penalized, and only a few at that? And de-registration won’t work with soil testers, because they are not required to be registered.
Why wouldn’t they just continue to ignore maps and stored satellite data on internet sites such as Near Maps, and Appendix D, which could require deeper drilling/more testing? Then they can continue to downgrade soil classifications that require cheaper footings.
Although thousands of slabs have distorted horribly, the chairman of the committee for the AS Code 2870 said in the case Softleys v Metricon Builders that the code was written in the knowledge that it was very likely that a few slabs and footings would fail. This was by virtue of the ‘greater good’ mentality of keeping the price of houses down via footings that don’t cost a prohibitive amount.
Frighteningly, the stage seems to be set for a repeat of the large number of disastrous grossly deformed mainly waffle-pod slabs seen in the last 10 years in Melbourne’s outer western suburbs.
And the suggested requirement that those selling such housing development land must carry out general and proper soil testing compliant with Appendix D of the AS Code 2870 to prove whether or not the land is actually suitable for average footings will probably not be legislated, even though it might prevent quite a large number of disastrous home builds.
A broad-acre representative dozen test bores, including a few in long-term dry-spots near where rows of trees were removed early on, would only cost about $25,000 – not a lot by any means.
Such a requirement might well lower the price of the land, but perhaps the land should be cheaper if house footings are going to cost well above average.
But governments are reluctant to place restrictions on development, even though a fortune would still be made with such a covenant in place.
And so, many building sites, particularly near where rows of trees once were, will most likely once again have inferior (non-compliant) soil reports carried out, as was the case with the Hoopers and Softleys following their repeated court cases against Metricon Homes.
Let’s hope the Mount Atkinson estate does not become another catastrophe like parts of nearby Tarneit and Gisborne all the way down to Point Cook, plus nearby suburbs in the outer west and north-west of Melbourne.
But will anyone inform the 8,000 unsuspecting buyers of those blocks of land?
We’ll just have to wait to see firstly, if the buyers are actually informed, and secondly, if the distorted slab problems commence soon after the houses come off the production line.
What else can we do if the federal government will not make AS Code 2870 foolproof and cronyism-proof?