Multi-dwellings: when does precast concrete walls become more advantageous?

Discussion in 'Development' started by thydzik, 11th Apr, 2019.

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  1. thydzik

    thydzik Well-Known Member

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    Hi All

    I'm familiar with brick (veneer or double) for multi-dwelling construction of up to around 3 levels.
    At what point does concrete walls (precast or tilt-up) become more advantageous as a construction method and should be seriously considered?

    Any thoughts appreciated, thanks.

    Couple of links I've found
    The Future Of Residential Construction Is Precast Concrete
    "precast as being the logical next step in the evolution of residential construction because it will save time, eliminate waste while allowing for standardised quality appearances and greatly improving the building process."
     
    Last edited: 11th Apr, 2019
  2. Westminster

    Westminster Tigress at Tiger Developments Business Member

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    By multiple dwellings are you using the Perth definition of it which is apartments (Class 2)?

    I would think 4 levels or higher but it would also be site dependant. You can have a tall skinny 4 storey vs a wide and fat 3 level
     
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  3. thydzik

    thydzik Well-Known Member

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    Thanks for the reply, yes in Perth, Class 2.

    I've got a 800sqm block zoned R160.

    Early feasibility stage.

    From what I have read,
    concrete prefab or tilt up are more expensive and you need crane hire.
    bricks are slower, and possibly more costly at higher levels.

    I was wondering if there was a general rule where it was clear cut which was better.
     
  4. Aaron Sice

    Aaron Sice Well-Known Member

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    I would say approx 4 floors and up, including any basement, would put you square into concrete walling.

    I would also suggest you look at a raft of options - AFS style systems seem to work well (with your kooltherm/batten/plasterboard lining internally) and then frame the entire inside out. I've noticed tilt-up just doesn't work for anything high-rise and precast *can* work but you need an on-site tower crane and setbacks.

    It doesn't matter if it's a wide or narrow site with the AFS but it's not as fast as pre-cast - but pre-cast is pricey lately due to mob/demob.

    The attached is AFS/framing and is only 450sqm and 10.5m wide. I would say it'd be fine for 800sqm odd. 44F.JPG
     
    Last edited: 16th Apr, 2019
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  5. thydzik

    thydzik Well-Known Member

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    thanks Aaron, good info.
    the concrete form is something to consider.
     
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  6. Aaron Sice

    Aaron Sice Well-Known Member

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    I think you'll find AFS / Logicwall is cheaper in the long run. I've just done the run up for a job in brick / AFS / pre-cast AND framing and the AFS/framing combo has saved about 15% on construction. It allows everything from lighter slabs to faster fitout to MUCH better wind-resistance / struct moment testing as opposed to brick/framing or just brick.

    AFS edges / corners are expensive, this is where it falls down when people try to bring it across to a typical resi installation with ins and outs everywhere. You're better doing any projections / recessions in framing.
     
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  7. Aaron Sice

    Aaron Sice Well-Known Member

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    There's also this amazeballs product called DINCEL out of Sydney for basements - 200 thick and because it's PVC - no tanking! CSIRO tested waterproof.

    Dincel Structural Walling

    Works really well if your joining details top and bottom and intermediate are well set out.
     
  8. Big Lez

    Big Lez Well-Known Member

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    Most of the job sites I work on currently use dincel/AFS walls. They are pretty quick and easy to install. I’m just a bit dubious with how well the render sticks to these products, time will tell!
     
  9. norwoodman

    norwoodman Well-Known Member

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    For a single dwelling one or two storeys, I can think of maybe one situation where using a pre-cast concrete wall might be advantageous, and that's when you've got planning approval to build a garage or similar area on or next to a lot boundary and the outside wall would otherwise be inaccessible to concreters, renderers and bricklayers (this wall would also need to comply with BCA requirements for fire rating, which a pre-cast wall does).

    Otherwise Dincel/AFS walls or other solutions are generally the way to go...
     
  10. Aaron Sice

    Aaron Sice Well-Known Member

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    Goes onto AFS no problem with the CFC sheet. Like acrylic rendering a framed home.

    Dincel - basement I'd leave bare and just paint, upper I'd clad.
     
  11. Kr@mer

    Kr@mer Well-Known Member

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    It would be brave to rely solely on the dincel for being water tight
    Given theres no way of determining if the walls are full of concrete
    The footing to wall joint definitely needs treatment.

    It all comes down to the workmanship of the trades too
     
  12. thydzik

    thydzik Well-Known Member

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    Aaron, I dropped you an email to further discuss if interested.
     
  13. Aaron Sice

    Aaron Sice Well-Known Member

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    Thanks. Always interested.