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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?

 
  • Placing concrete slabs on the ground surface to hold up the whole house was invented in areas of the world that had stable dry soils. In Victoria we have everything. When we design temporary houses that only have a life of twenty years you can use a concrete slab. If you want houses to last longer you need footings to be based at least three metres deep in certain areas. The unforgiving nature of concrete on the ground means often there is no way to fix a mistake. Cheap semi-skilled labour also produces cheap results.
    At one stage concrete slab houses used to cost more than timber floor houses, but as more and more people became familiar with concrete it has become the basic standard. The cheap semi-skilled migrant labour of Melbourne’s western suburbs has meant that concrete has taken off. To build a timber floored house now costs more, as carpenters & timber supply costs more.
    Just as we have seen concrete skills become available the thing that has been happening in the background is the better prices for screw pile footings. The western basalt plain of Melbourne should have raised timber floors on screw poles with adjustable tops.
    The main problem is the fact that it’s hard to change supply and labour skills overnight. It’s still cheaper to build a brick veneer house with a slab and a tiled roof than anything else. If you look through fences and see how things are done you would not built a house for your Grandson with a concrete slab on the surface of the ground.
    The future is screw piles with prefabricated floors, walls and roofs. The only thing that will stop it is the import of very cheap unskilled guest workers as we have seen in the USA; or, Government undermining manufacturing and the free trade economy.

  • If builders correctly drained the construction sites as the are required too then we wouldn't be discussing the heave issue.
    In several heave VCAT cases the soil testing companies were found not to be at fault and the builders were deemed liable because
    the filed to grade the soil away from the foundations as per AS2870.Builders also fail to use temporary downpipes during construction.
    It is easy to point the finger at the geotechnical industry but if you go to any new subdivision in ANY estate you will not find a construction site that complies with the requirements set out in AS2870…….. NOT ONE!!!!!
    Builders poor drainage practises create abnormal moisture conditions during and after construction and the slabs are not designed for class "P" abnormal moisture conditions.
    So the question must be asked : Why are building inspectors passing poorly drained site that do not comply with the Australian Standards.And why have the inspectors not be prosecuted.
    The answer is simple the VBA is a toothless tiger and would rather setup a Domestic building disputer resolution department(effectively a large mop) rather then enforce the regulations and prevent the problem in the first place.
    So you can blame the soil testing industry but until the drainage requirements are enforced before and during construction we will be going through the same problem year after year regardless.

    • Hi Jason, Good point. I have also experienced this careless site management. It also causes problems when builders continue to work in inclement weather, especially now that excavator drivers are sitting in a nice heated cabin….continung to dig in the pouring rain. Dry site….to swamp! I think we should be pointing fingers at the pre-slab inspectors as much as the engineers/ soil testers. Draining water away from a house is fine….until they are all so close together. So many times I see one house graded away over 1 meter as required by the BCA…….and as a result, the water is moved away from one house and straight under the neighbours garage.

  • Mark, thank you for pointing out both the role of Governments in implementing its strategic 'policy' of allowing 'strategies' for those in the developer/planning/building space to extract money from ordinary Australians and to knowingly rob them and expose them to financial loss and the inherent safety dangers. All for the greater greed of themselves and their 'business beneficiaries'.
    The soil testers are a very suspect group. I personally have seen many cases where these 'testers' have either not done the testing at all and 'made up' a pretend soil test sheet, or changed the soil test results to accommodate the builder and his buddies who are all willing participants in the construction con. Everyone knows the consequences of ignoring the soil type. And as we know from the recent Senate Inquiry slab and footing 'Standards' and the 'Code' are treated are irrelevant – builders do not purchase copies, do not read them and therefore ignore them! Thus, the reality – we have an industry of 'NO RULES'.
    As for 'slab heave', the policy is "heave ho and away we go", and "Let's make more profits". The corollary of Governments is: "Let's also help the building dispute industry continue to skyrocket!" There will be NO informing consumers or the public! This would definitely not be in the 'profit interest', and hence to assist the crooks this 'no information' to the public is incongruously termed 'in the public interest'! NO RIGHT TO KNOW – just as with Lacrosse apartment owners – they only the minority among 1 Million Australians harmed annually, both financially and in every possible way. If they could 'know', they would vote with their feet and walk away, not sign up to be victims. This now confirmed by the Senate Inquiry to be what we (you in the industry and we consumers) have known for decades; we have Government sanctioned 'policy' in the "interest of business" – in effect, 'legalized' fraud on a grand scale!
    Keep up the good work Mark! I hope more decent souls will join us in saying it is time to stop. I'm praying!

  • Good points Guys. You are right about prices reducing over time for new techniques but the short-term is the problem holding back deep pile technology with young new home seekers not about to reduce the size of their homes just for guaranteed stability of their homes. And Jason, very good point about incorrect drainage usually being the reason cited for the failure of the house waffle pod slabs… but that was in the short-term, and that was not the basic problem but the symptom of the real defect… the incorrectly classified degree of dryness deep down inadequately catered for… because of short-cutting of the soil reports. And Anne, the system is not only broken in so many facets which all lead to down-trodden building consumers, who seem to sail forth into the sunset completely ignorant of the huge number of serious problems out there, because they are not reported sufficiently in the media, and virtually not at all by the authorities. The Governments and the Herald-Sun seem particularly deficient in this regard, perhaps because they are hell-bent in protecting business at the expense of consumers.

  • I have a question for everyone. Has anyone heard anything by any authority to the effect that the stream of failing waffle-pod slabs must be averted no matter what the cost?.. before Victoria makes the problem much, much worse. Blocks of land in such poor soil areas are selling at a rate of knots to thousands of unsuspecting buyers at an average of over 230 per day.

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