Mirvac Harcrest Wantirna Stage 6 - Site Costs and Fill

Hi There,

We recently settled in stage 6. Soil test revealed 15 Metres (More than 50 feet) of fill. Site costs are working out to upwards of 100K.

Have any other come across similar situation with soil test and site cost.

Wow that is a lot of fill. Do you know the reason for it? Is it level 1 certified? Assuming its well compacted and safe to build on, shop around, I am in an estate with a lot of level 1 fill (nowhere near 15m!), and most of the builders are coming in with normal-ish site costs for our area, a couple have used screw piles adding a fair bit of cost, and rumour has it one of the very big builders doesn't give a hoot about the fill and has very low site costs. It seems to come down to the individual engineers approach to the problem.

The reason is that the number of plots in this stage were part of the pit in the austral quarry and has been filled says level 1 supervision.
The building engineers are now sceptical of designing a foundation given the amount of fill. Significant cost overruns.

Hi Randomone,
sorry to hear that your site cost is over $100k. Which builder ?
I am building with burbank and the site cost is fixed @$13k. Of course may be my land is flat. Shop around and ask other builders

Geotechnical report...What fill, Controlled or uncontrolled, bearing capacity,Bore holes, sampling, soil profile,type footings? etc,etc?
$100k needs to be justified or is that just what the salesman is telling you?

Hi There,

We recently settled in stage 6. Carlise Homes has recently informed us that they will not build for us giving the reason that the amount of fill is too deep.
Anyone experience this problem? Any suggested solution? Will the house have any problem after building?

Hi Novice 000

Where in stage 6 are you? some parts are deep fill others are natural soil.The fill is very good (well compacted and clean)
but very deep.AS JAMES GEOTECHNICAL has done a lot of compaction reports and testing in that estate so there should be plenty of information available to the engineers.

Hi Insider

Unfortunately AS James did not conduct the test on our piece of land. The only did for our 2 neighbour land. They told us there is no point doing one specifically for us as the result will not vary much. Our lot is just next to the Mirvac Town houses.

Did Carlisle do a soil test on your block or did they use AS James existing subdivision report?
Did they charge you for a soil test?

Yes Carlise did a soil test but they decided to base on the AS James report with the 15 meter fill.

They said they will return us the full deposit and not charge us for the soil test that they did. Their soil test report - Horizon - Fill, Hole 1 (mm) 0-4500, Hole 2 - 0-2800, Hole 3 - 0-2800, Hole 4 - 0-4800 and hole 5 - 0-2800.

Of course I do not understand what does the above results actually meant

It means the found fill all the way down to 4.8m and did not encounter natural ground.
The may have finished the test in fill because the cost of drilling to 15m would be significant
and it would just confirm AS James report.
The engineer in these situations usually has two choices
(A) A rigid floating slab designed to withstand significant settlement ,if the fill is good enough or
(B) Screw piles to natural
100k may mean the went with screw piles

Thank you for the explanation. Much appreciated. Very helpful indeed.

Hi StructuralBIMGuy,

It appears that you are a professional who works in the building industry. So here I am, would like to ask you some Qs regarding a borehole at the front of my Lot.

The Geotechnical Report from A.S. James for my Lot stating that an approx 12.0m thick fill was encountered... The fill was placed under controlled condition to a minimum 98% Australian Standard Compaction and supervised in accordance with the Leave 1 requirements as set out in AS3789 guidelines.... The site should be classified as Class 'P' in accordance with AS 2870-2011. However, considering the method adopted in placing and compacting the fill, th site can be re-classified as Class 'H2...

I cannot find bearing capacity, sampling and type footing that you mentioned above from my report. Do you think the borehole might cost us a lot in term of site cost? The fellow poster Novice 000 said Carlise refused to build their home because of 7m fill that they've got. I am currently with Carlisle, do you think they might refuse to build for us as well due to the 12m fill? Any good suggestions?

We went to colour appointment this morning with Carlisle. Our CLE told us that they did a solid test already, will let us know the result next Mon or Tue? Very nervous about result Wish carlisle still able to build our home, and site cost wouldn't be toooo expensive.

Your response will be much appreciated!

Cheers,

Greenapple

Green apple

Any follow up after your meeting with Carlisle ?

Hi greenapple
if it's a geo tech firm that builders use all the time then
1. Site reports are generally written the way builders want them to be written..some comprehensive ..some not?
2. IMO you are paying for it so you should be able to contact the report writer and ask for additional info
3.The footing details options will be designed by a structural engineer based on the site report..and the builders preferences
please leave a pm