Slab heave is alive and well, watch out.

Recently I was called to inspect a garage attached to a ranch style home on acreage north west of Melbourne. The owner has noticed some cracking for years but recently it seemed to become worse and it appeared that the garage wall has come away. The home is approximately 14 years old, waffle slab (out of builder's warranty).
On arrival, as I got out of the car I immediately noticed I was grabbing Tiger by the tail. Yes there was clear evidence that the garage side wall has subsided, a bit more worrying was the impression that the whole dwelling has tilted the other way. Checking brickwork with a spirit level it confirmed dwelling tilt. Then I set up my automatic laser level inside the dwelling and confirmed 75mm tilt along the length of the dwelling.
Reviewing the construction drawings I established that there was supposed 600mm cut at the garage end and 300 mm fill at opposite end of the dwelling which wasn't there. Instead there was gently sloping ground surface toward garage wall (that subsided). There was supposed AG drain along garage wall but I could not see it and owner reported that it was close to the slab edge (if so it was merely a watering system for underside of waffle slab). Owner did not have own independent inspector during construction and no one picked up that builder did not carry out site works and drainage as designed, and the building was now 14 years old and out of warranty.
What happens now? Owner is downsizing and will sell up.He will fix the garage wall but the dwelling tilt cannot be fixed and with time may become lot worse(75mm heave may have already cracked sub floor drains). Owner is hoping that the potential purchaser will be stingy and will not commission a competent pre purchase inspection or that the inspector is a dud. Lucky for him there is plenty of them around.
RU in the market for idyllic ranch style. lifestyle home on a few acres? Honey or a lemon? A competent pre purchase inspector may make the difference.
If you are building or buying without your own competent independent inspector, get a medical, see if you have rocks in your head.
Everything you read above was deja vu and just a replay for me for I have seen the same problems (badly heaved or tilted homes) before and many of my pre purchase clients have walked.

Hi. Branko I just found out that the soil test Done on my block of land was never actually done yet the builder gave me 8 page soil test saying that it's
M classification now that i have this proof they lie and falsified documents saying they did the soil test. Now i showed my solicitor in my big surprise I was told that Vcat is not intrested in hearing this, how is this even possible so these big company's can do this and not be held accountable the fact that Vcat don't want to know it tells me that us as the consumer are paying lots of money for things that are not even been done and tested so ask your self why have we got slab heave Hummm to me this is corruption but our legal system let's us down to protect big company's in the name of keeping the building industry working but at what cost. These company's know the majority of people cannot fight builders and take on engineers as well and pay a mortgage on their new homes this is why vcat is designed so we cannot afford to fight a builder.
Iam planning to bring this in the open by going to the TV stations and all radio stations people need to know this. And some how I will get it out there. It makes me sick that this happens in Australia and government departments are allowing this to happen how sad. Shame shame on them VBA BCA the AS 2870 has been watered down so much that defects are built into new homes then they call it part of our maintenance I would love to ask the member of vcat what is a defect and why? It was taken out of the AS 2870. We need answers.

Unfortunately for many years (at least since AS2870 came into existence), consultants in VIC have relied upon the supplied information in AS2870 Appendix D which allows for a site based classification to be completed based upon solely a map. This is not below the law and basically industry wide. This is changing, partly because of the legal implications of some high profile cases which have been before the courts. A lot of major builders are now progressing to full soil testing and sampling etc. I will reserve my judgement to see if the consumer signs up for the costs.

Unfortunately the "defect" classification has always been listed within AS2870 since its inception in the 80's. The problem is, that many builders have never expressed to their clients that the limitations of designs which COMPLY to AS2870 also come with some risks and if a home owner is not to accept the risks then they should ask for a fully engineer solution which may suit their expectations.

I always try to explain to a home owner when they call for a chat/talk/interrogation that if you choose to build a home which is designed to comply with AS2870 you have to expect the risks of Appendix C. Many immediately say we cannot accept that and I then move on to say well ask your structural engineer to design a structural system which will meet your needs. Although I rarely see the end product I estimate around 70% of home owners cannot justify the cost and instead choose the AS2870 performance criteria.

AS2870 was designed purely for the masses and with mass production comes consequences with design.

My point is, your classification and defects (I assume you have some) may well be within (or may not), tolerances of Appendix C of AS2870, the question you must ask is," why was I not informed of what "tolerances" my slab would have when I signed up". Then ask yourself, if you were in a position to pay the dollars to ensure you had a dwelling which "WOULD" perform within "YOUR" tolerances.

Hi Geo1
Can you explain this for dummies?
What would you do if you were building?

What is the best way of mitigating risks?

Thanks

Hi Gaudi, and thanks for the question. And a very good question at that.

AS2870 was formulated to give "standard" designs for basically mass production and whilst it servers well for 95% of projects there is always the 5% of projects that unfortunately "under perform". This conception of under performance is often a case of the end consumer believing that they have not obtained the product that they were promised or perceived to be promised. The tricky situation occurs when the designer/builder/engineer/authority has to explain to the end consumer that the product is actually performing exactly how it was designed. Try explaining to a home owner that has just forked out a large sum of money that a 5mm crack in their gyprock ceiling is actually within tolerance and in fact a not a defect or structural fault.

This was basically my post above and also my disappointment and my continuing business objectives with the industry. If the end consumer is presented with a copy of Appendix C of AS2870 at point of sale (happy to upload a copy for all interested), then the end consumer could form a "educated" opinion as to the performance criteria of AS2870 design and complied slab designs and whether the risk profile suits their needs/objectives.

It is very different in my opinion to present Appendix C to say an "investor" or a "owner occupier". There is always the trade off between risk and reward. Not just in construction but in every aspect of life and business.

Any client that contacts me, I always answer the question with the following statement "If this was my house and knowing what I know and doing what I do on a daily basis I would be doing this.......". Now as you can imagine this generally gets a very good response however I am not the one paying the bills to the builder and trusting the engineer and therefore I can only give professional advise based on professional knowledge and training. I CANNOT convince the home owner that they extra $3,500 worth of concrete and steel is necessary inclusion and that without it they may have problems.

I always explain to clients that I cannot comment on building costs because each builder will have their own building mark ups etc, however I can explain that the inclusions are necessary for reasons xyz...Depending on State or Territory you are building in unfortunately the regulations govern basically your standard of engineering and geotechnical testing. Everyone relies on AS2870 however the level of which the testing and engineering complies is based basically on the risk profile of the builder and how much they are willing to pay for the service (in turn the consumer).

I have been told many times by a large Australia based client of mine that we are the best at what we do, however we are too expensive to provide them the product and therefore they engage consultants who may or may not be within compliance with the standards.

In simple terms, to answer your question, I always instruct my clients to ensure they pass on my details to the consumer and inform them they are free to call me with any questions at any time. The answer to your question is, ask questions, if you cannot get a response that meets your expectations or doesn't feel right call the geotech and call the engineer. If then you are still unhappy, engage a licensed, insured consultant to give you a third opinion. That $400-600 in metro areas may just save you $100k's of problems down the track.

Regards

Geo1

The problem with VCAT is that it is a Civil Tribunal and has no power or interest in penalising builders (or owners) that lie and misrepresent. This is despite the fact that VCAT is in the best position to punish the builder(or owner). VCAT will hear cases and award damages as compensation to owners but nothing more than compensation (so you always loose because of burden of proof+your legals).

Good point from Geo1 about 5% of under performing builds. That is 5% of shattered lives in the community and with 25000/year builds = 1250 families/year affected. It is a regulatory failure on a Titanic scale to allow builds on estates with highly reactive soils without catchment for those owners who fall between the cracks.
Firstly there should have been a fund created for those whose homes that are affected but not declared defective.
For those homes that are badly affected to be declared defective there should be automatic buyback for demolition.

If the slabs have to be engineered so what? Its the cost of big screen tv

The other point is that regardless of engineering or site reactivity the biggest contribution to slab heave is builder's incompetence and negligence. As I write this I regularly report on defective site drainage during construction, that is despite builder's taking owners money and promising to deliver engineered product but failing to follow engineering specification on drainage.

One of the posters had his site severely flooded during construction for extended time, deteriorating his M site into P site with M slab on top.

This is Not a reply to anyone. Its a question. I would like to ask a question to anyone that can answer it, if I hire a geotechnical engineers to do a soil test on my property he/she by using a mechanical Auger this is a big unit, after a few weeks I receive my report with M classification I use this to have my slab designed then the house built. All good right now after few years I find out I have slab heave now iam concerned after some investigation and by chance I have taken photos of the property few days after the date of the soil report and I notice that I cannot see any signs of any mechanical Auger drilling any test holes, remember they drill 3 test holes the day they came it had rain for 3 days to my understanding shouldn't the're be signs of a mechanical Auger on site or sign of the holes which are between 2 metres and 3 metres deep it sould tell me and show the geotechnical engineers actually did the soil test. My house has bad damage who is responsible for the damage.
1. The builder who built the house.
2. The design engineers who design the house.
3. The geotechnical engineers that did the soil test and failed to even go on site drilling the 3 holes and actually test the soil at a labotory.
Who's responsible for my loss. Who is responsible for the problem. Because at the moment my issue is no one is talking responsability and are blaming each other for the issues iam having that leaves me out in the cold and a faulty house that I cannot use I cannot sell.
I would love to hear from anyone who can tell me which is at fault since the legal system and vcat is not even interested vcat don't even want to know about the geotechnical engineers so how do we as the consumer hold these people accountable.
Thank you.

Geo1 how frustrating for you to have builders say they find professionals who will use a cheaper design that is likely less effective.
As a homeowner this attitude from builders explains why there are so many owners with issues a few years after the build.

It would be great if builders were to all permit owners to talk to their engineers and geotechs

I have read the AS2870. I’m going to refer back to the appendix c with your explanation above in mind.
Thanks for taking the time to explain

Can you post the photo of your block after the soil test?

This is before the build that week it rain. This is a few days after the date on my geotechnical engineers report. No sign of Machanical Auger here specially they had to drill 3 holes, i have other photos i think this shows that this land is untouched not disturbed at all.
What are your thoughts on this. No Machanical Auger. Untouched land by any machines. As you can see. Acording to the report i should have a hole directly in front of me one the right of me the other directly in front thr 3 pegs that mark where the water mains have to go.

Hi Mauromario,

Thanks for the photo.

Now i do understand your concerns, and I will concur I often get asked this same question from home owners who have engaged builders of which I work for. Hopefully the following will give you some answers/follow on questions you may ask of your builder;

1. We run 3+ tonne drill rigs of which have the capability to drill to 40+metres in soil. In certain states (NSW mainly), many drill rig are only capable of drilling to 4metres (maybe) depending on soil conditions and are generally run off 4WD single cab utes etc. (Trust me if the ground was wet. you would see truck tracks although the site). Fully equipped drill rigs are not light. Maybe 2-2.5tonnes at the lightest.

2. Generally the hole diameter used is 100mm solid flight auger.

3. We do use portable equipment (i.e hand augers, especially when vacant sites are wet and our clients (builders) are pushing us for results), which generally are limited to 1.5metres (although my kit on my ute has an extension which will go down to 3.2metres, providing you can actually physically manually drill by hand (muscle) that depth, which is very tough if you ever have the experience of trying.

4. I always tell clients if we have done our job properly you will not know we have been there.

With regards to the above (especially point 4), there are always the exceptions and this is where I will agree with you. Check the boreholes report and it should have a reference to whether a "hand auger generally abbreviated H/A) or a power auger (generally abbreviated P/A), has been used.

Finally, regardless of how good we may be, you should still be able to find a hole. I always tell clients to look for a little "ant mound" as you can never really compact all the soil back into the hole after drilling no matter how hard you try. My guys are instructed to "ant mound" the soils as when rains occur the soils will settle and the last thing we want is a 30mm depth x 100mm hole left on site. Legally thats a trip hazard and well lets face it, no one wants to trip on a soil testers hole.

Regards

Geo1.

Thanks Geo1 for your reply which is very helpful and I do appreciate it, as to my report it clearly states in bold and Capital letters a Mechanical Auger was used on this site. There was no refusal from 700mm to 1.8 metres i can post the so called findings. I know going by the photos that I have. I do have one more facing from the front and others but those have names iam not ready to share those at this point. As you can see no testing was ever done so they say its a
M classification soil i have the proof soil test was never done, I have seen how big these Mechanical Augers are so they should have left some sort tracks by the ute or truck, and after drilling 3 holes and after 3 days of rain. They have falsified documents, Why is it Vcat don't want to hear about This even my solicitor tells me this so even though they are hired by the builder thats a breach of trust and breach of the law against all consumers regardless who pays the bills these people are cashing in and taking huge chances in the hope no one will ever find out or even consider that an geotechnical engineer would do no wrong. But the law according to vcat they don't won't to know due to this answer (HOW DID THE GEOTECHNICAL ENGINEER CAUSE YOUR LOSS ) Iam dumb founded. So at some point Iam going to bring this in the open in the media am sure they are hurting other company's that do the right thing like you guys.
I just don't understand how they are not held accountable for not telling the truth. No wonder we have slab heave soil test are wrongly been documented and actually never done. I cannot say who the geotechnical engineers are at this point.

Thank you kindly
For your time. My fight to date has costed me a small fortune and not even at Vcat stage.

Mauromario,

I am not familiar with the VCAT system unfortunately, as all my work comes from the east coast of AUS. But I am familiar with the QBCC system and I am sure its not that dissimilar than then of the VCAT one.

I think in an early post I expressed that in VIC it was (and still is) not uncommon, (if fact prior 2016 this is how generally it was done) to use the data available in Appendix D of AS2870 to ascertain soil classes throughout VIC without doing a soil test.

Now this is an entirely different manner then what you have stated, where you have a soil test of which shows three(3) boreholes done on your site.

Have you had an independent soil tester confirm or dis concern the results?

From there have you had an independent engineer confirm the "design" based on the "independent" soil test.

VCAT like the QBCC will not really be interested unless your damage is outside the Appendix C Category 2 damage criteria.

This goes back to my entire post about AS2870 performance criteria and the expectations of home owners.


Regards

Geo1

Most soil test reports will include a photo of the block taken by the technician doing the test.
Compare your photo to the one taken by the soil testing company they may have tested the wrong block by mistake.

Hi building-expert,

Thanks for the comment and I already hold you in high regard based on your comment about "drainage".

A lot of builders do not still understand (even though its documented in AS2870), that they are responsible for site drainage at day of builder contract commencement.

I do not know how many times I have inspected house slabs where it has rained the day before or the week before but their is water ponding around the edge beam. This in terms of AS2870 entails "abnormal moisture conditions" and therefore the site becomes Class "P" and logically following the original design becomes null and void in a sense. We recently did a study of a vacant between two houses underconstruction, on the left side, the dwelling's down pipes was connected via temporary piping to the stormwater pipes and on the right hand side the dwellling's down pipes were left to run onto the ground. We conducted moisture samples ever 200mm down to a depth of 4metres.

The difference in moisture content was literally 40% after 2 weeks. Both builders were not our clients thankfully, but we did have access to the vacant site in between.

Now to a lay person this does not mean much, but in terms of what we do and the implications of AS2870 this was massive. Does this mean the vacant site in between was subject to "abnormal moisture conditions" constituting Class P conditions and extra site costs to the potential owner of the vacant block of land? The moisture gradient from one side of the vacant block to the other was massive. Who is responsible? The developer who sold a Class "M"? or the soil tester on $400 budget and didn't conduct moisture testing?


In terms of your post the only thing I disagree with is this,

"If the slabs have to be engineered so what? Its the cost of big screen tv"

Well yes the cost of engineering a slab(i assume you mean the design aspect as in the cost it takes to pay an engineer to design a slab not the cost of actually takes constructing the design) is most likely the cost of a big screen tv.

But the cost of "constructing" an ENGINEERED designed slab that performs well above Appendix C of AS2870 in the eyes of the consumer generally results in site costs over an above $50k.

AS2870 again I will repeat it, its a cost/affordability/expectation design.

If the builder presents the client with a copy of Appendix C and states "you want a standard design here are your risks", then "this is what you have to tolerate". The sooner the industry will change go better engineering (although in most instances substantially more costs), then the better the industry will be. Present the facts, deal the the consequences (on both sides consumer and builder) and everyone wins.

Regards

Geo1.

Ha that's a good one we never got a photo with our soil report, I was not awere that they take photo of your block of land, our reports were not even stamped or checked by the RBS go figure that out. I know the builder has a lot to answer for but the geotechnical engineers are just as bad, for not being honest.
Iam Victoria I hoped you guys are as well I know Geo1 is not but great help thank you at the moment Victoria is allowing all this to happen in the name of keeping the building Industry working but at what cost. I built my house in April 2010 and 8 years later my house still moves like a yoyo heave is so bad that it's pushing the roof tiles upwards lifting some of the tiles. Roof trusses have pulled apart exposing the 90mm nail in the frame work. I've had in total of 8 floor levels done in 12 months and levels are out by a lot, and very room has moved up and down, My airflow pipe for toilet and heater flu are so bent over its crazy.
All I can say is in 3 years that I've been fighting this I have learned a lot and lawyers are cashing in on this as well so everyone makes money out of us poor consumer's its a real shame that people like this are not held accountable by the law, i really want to bring this out in the open when the time comes.
I really appreciate the help I have received on this forum it shows me there is good honest people out there so thank you I'll keep you guys posted.
Regards

Many a time have we confused photos with job numbers..... It happens.

Thankfully, 99% of the time we get it right.

But still does not hurt to check.

Most soil testers are doing in excess of 500 sites a month and therefore, sometimes the old DSLR gets confused when uploading.

We try and make a point of the guys taking a photo of the job number/file first and then the site. This means when they get back to the office to upload for the day they know when one job's photos stop and the other other one starts.

Thankfully technology is helping, where we have cloud based servers uploading photos from site instantly.

Regards

Geo1

Hi Maruomario

Based on what you have described, I am out of words to describe how VCAT would not take this case up.

More then happy to put you in touch with some people that may be able to help in VIC if you personal message me.

Can't guarantee anything but there is always no harm in asking especially from what you have described.


Regards

Geo1.

Hey guys iam going to show a little of my build during construction and you can see what issues i have today.
This is June 2010. I have over 500 photos from start to finish plus another 700 photos from 2011 till now with tne propblems casused by this.




Trusses coming apart showing 90mm nails from frame and also sign of water under roof tiles this from 2017 thats just one photo.


Kitchen Have a look at big long crack next to plate of handle of shutters and plaster been streached so much that the tear has a line across and had to cover this with clear contact as well, on the right hand side of photo big hole in plaster i had to cover it with clear contact to stop bugs from getting in, this photo from 2017. This wall i can move it with my hand if i push on it, its come off the slab nothing holding it in place totally buckled wall .


I forgot this photo from June 2010 looking from bedroom window water all around the house, plus they had removed the rear side fence to get access to next door to bring bricks and other materials with a bobcat now this is driving on top of new waffle slab still very fresh from garage entrance i have a rear door as well.
I have much more. And as i said now i have a slab which was disigned for so called M site soil i think this should it have changed to a P before the build since the drought broke late 2009 early 2010 it rained every day. It was wet like this all of the 8.5 months of building. I really thought to my self dam has not rained in 15 years now that iam building its raining every day.
I would love to hear from you guys on any feedback would be great.
I think this is all i can share for now this is me been angry with the system that helps builders get away with distroying people lifes.