H1 and Rock underneath

Discussion in 'Development' started by Samj, 14th Dec, 2017.

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  1. Samj

    Samj Well-Known Member

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    We have been planning to buy a land and build a house. We have received the Soil test results. Apparently there are some complications as they found rock in all three boreholes. Builders can't give an exact site cost before doing the contour survey. Can't wait too long as land contract goes unconditional next week. I am just wondering if you guys any experience on such a land? I am trying to find out the worse case cost to build a 40 square two story house. Thank you.

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  2. Mark77

    Mark77 Active Member

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    From what I understand building on rock is not necessarily a bad thing. Depends on the style of house. Also depends on whether the rocks are connected or floating. Were you planning on building a slab house? Perhaps a suspended slab or pole home might end up being more suitable to the site. Would that be a major issue for you?
     
  3. Samj

    Samj Well-Known Member

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    Thanks @Mark77

    This builder's recommendation is 1m slab for this land based on soil type. They found rocks in less than 1m. That's the issue...
     
  4. Scott No Mates

    Scott No Mates Well-Known Member

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    @Samj - it will be totally dependent upon several factors - slope of land (we've got no indications of whether the block is steep or flat), where the building pad is going to be or the type of construction.

    For the most part, you should consult a structural engineer to discuss footing options based on the construction type.

    A conventional slab on ground (cut and fill), deep edge beams, waffle slab, strip footings with piers, strip footings with isolated brick piers (for timber floors) and many more options are available.

    You may not need to go to rock (& it's not that deep or hard). You will need to get the builder to provide their rates for excavation in rock (extra over) & definition ie needs a rock breaker not tunes and bucket on excavator.

    Engage a quantity surveyor @WashingtonBrown @BMT Tax Depreciation @Depreciator to confirm the costs that would apply.
     
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  5. Samj

    Samj Well-Known Member

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    @Scott No Mates Thank you very much. In that case I would like to have independent quantity surveyor. Do you know roughly how long and how much it would cost? I would like to get that done before the land is going unconditional.
     
  6. Samj

    Samj Well-Known Member

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    And also 1m slab means huge. Does that make any sense to have a 1m slab if soil type is H1?

    There is only 1m fall over in the buildable area in this land. Land is not too bad other than this rock issue...
     
  7. Sackie

    Sackie Well-Known Member

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    Talk to a structural engineer for options and their opinion on costings. Also talk to a QS to get their feedback on costings. You will have a good idea then. Also depending on your build, an architect may be able to design the building pad to minimize impact but it may likely need more bore holes to check around the site. I had a similar site and I requested more then 3 holes so I have a good idea for most of the lot and not a smallish area.
     
  8. Scott No Mates

    Scott No Mates Well-Known Member

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    Ask a QS. :rolleyes:
     
  9. Samj

    Samj Well-Known Member

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    Thanks for showing the direction. Does anyone know a good QS in Brisbane area?